Category Archives: For Freshers

AWS DevOps Course for Freshers with Project level tasks:

This course is designed for the Freshers by a three Decades globally experienced IT professional after studying many consulting projects and the skill gap issues of different project teams.
They can show these course project tasks, done by them during the course, in their profile.
The participant will be able to attend the interview for an AWS-DevOps fresher position, along with the live screen test without a Proxy interview. Interview preparation coaching will be given.
During the job; they will be honored for their skills learnt from this course and self demonstration in the team to complete the project task before the schedule. This can add value for the candidate’s future appraisals and for their IT ladder growth.
Its Purely, A job oriented course for Freshers with Live similar project activities through IT experienced professional. You will be enforced to do the tasks in the session. The Coacher/trainer will not touch the screen for lab demo.
Note: All the tasks the student will do as a demo in the session. Before coming to the demo he/she need to practice through material given to them. This makes the participant highly self motivated with confidence on technical learning. It motivates them for the job activities also, during their job.

For the course details, watch the below video:

If somebody want to attend the Basic AWS Course, before understanding the AWS-DevOps course they can see the below video and come for a call to know the details on it.

NOTE: This play list contains the videos made on the list of AWS courses made for freshers. The freshers when they are in project, they need to understand the infrastructure requirements and their tasks. During the course they coached on these areas well. And also they will be enforced to do some project activities with a requirement. And they need to present it in a team. This can give very high confidence to them not only to perform well in the interviews and also on the live project activity comparatively with many proxy interviews managed freshers.

https://www.facebook.com/watch/347538165828643/309818167129036/

Coaching: How the traditional IMS roles can be transformed into Cloud Services roles ?

To know the history of the IMS roles till the Cloud era, you should watch this video.

What IT roles can vanish with Cloud transition ? 

If you are in the below roles, in the current recession you will be targeted for pinkslip among the IT professionals as 1st exit group. What you need to do on your career replan. Please see/follow the blog/videos with patience. 

As per my observation and practice with the trending technology [Cloud], all the Cloud services vendors have inbuilt serverless computing for many services. The following roles are going to be vanished or reskilled. But if they are kept under recession staff cut, these professionals need to take care of their career.

1. DBA:–>The DBA tasks are embedded as part of these services. So the DBAs used to sit hours together in the past to perform many mundane tasks. Now these all are automated. For details you can see the below video:

2. Similarly, many other tasks are related to infra roles; Network admin/Sys-Admin are also automated through Cloud services.

3. As a consolidation all these 3 roles are clubbed into one role of Cloud Engineer. This role’s major task is to automate all the Cloud setup related activities under IAC[Infrastructure As Code]. In future only the IAC will sustain to save the cost to IT by automating the cloud setup creation activity.

4. If any professional need to compete with this role means; they need to understand the Infra needs and the past roles tasks in depth. Along with the multiple Infra related architecture scenarios, with in-depth knowledge on Cloud technology. Then only they can analyze the IAC requirements clearly to write the code and test it. This is the domain analysis and design activity they need to consider apart from the Cloud technology learning.

5. We can also see the Storage engineer role. All the Cloud vendors have the Cloud Storage services. With them mundane tasks creation/maintenance is vanished. Hence this role also will not exist.

IT-infra-Roles
IT-SDLC-Roles

The below video has the discussion on: A) What IT Roles can vanish after migrating to Cloud? B) How the roles/tasks are being transformed to Cloud through serverless computing technology ? C) Why anybody can learn and do the past Infra roles with Cloud ? D) What all they need to learn ? E) How the organizations can demand an employee to convert into modern technology before taking a decision for a pink slip serving ?
Finally, what are the following roles and their tasks:
Traditional Infrastructure building roles:
1.Network Admin/Engineer
2.System Administrator
3.Database Administrator
4. Deployment Engineer

Technical Roles:
1.Developer
2.Test Engineer/Analyst

F) Among the above which role can pickup faster the Cloud/DevOps Automation technology ?
G) Then How these roles can perform in Cloud  with faster deployment ?
H) Why and how the manpower reduction happen after Cloud implementation ?

I) Why do you need to learn from the experienced IT mentors to transform into modern technology ?

K) Some people say, they can learn by self. How much they can learn and cope-up with the current market needs on various technologies to settle in modern technology ? [refer to point#5 in this blog].

L) Why do you need to spend/invest  more money to re-settle in the modern technology ?

Note: Along with this video, there are multiple blogs I have published with Videos links to make awareness to the IT Professionals. You see those blogs from this site itself.

For further understanding please read the below text:

In the current IT World Cloud computing became regular practice for any IT Professional. Any cloud services we use, we need to know the current/traditional infrastructure setup. But every IT professional may not have that background/knowledge to understand. Because in this industry each of us played  different roles.

The Infra activities handled IT Professional only will come to know this knowledge and will have experience. But the industry needs every IT employee need to know this knowledge apart from the Cloud service provider [Ex: AWS, Azure, GC, etc..] products operations. [Eventhough, if you are a certified Solutions architect with that Cloud service provider.]

Then only whoever the professionals are certified they will be able to use these products/services and implement them under cloud setup. Hence the Infra domain knowledge or experience is mandated for every IT professional who is working for Cloud services or in that infra setup. I have been hearing during Cloud professionals recruitment the interviewers are keeping some questions on this area also. If one understand the Network domain setup then only they will be able to design the Cloud architecture. Hence more employers are worried to have this domain knowledge with the Certified and recruited Cloud professionals.

I have started a Cloud Practices group to educate/share the IT professionals with this domain knowledge. The below link can be used to join/apply:

https://www.facebook.com/groups/585147288612549/about/

Note:

Cloud/Devops: How the ITSM professionals can be reused ?

Cloud/DevOps: Rebuild ITSM for Cloud/DevOps:

The Traditional ITSM professionals do not have option, except converting into Cloud/DevOps roles with the relevant tools. How this methodology works in a project level from an individual, what skills one need to be groomed: Watch the video and its description. This kind of practices a COE need to follow if the IT company has the financial capability to run the COE building at this stage instead of loosing the knowledgeable guys. Or the individuals need to open their eyes to switch their career by taking experts one on one coaching.

Rebuild Your IT career from ITSM to Infra and DevOps building with traditional exp.
I have not included the real ITSM roles. Those also can utilize into the conversion. Case to case it can be discussed. Each Organization has their own title and using them for ITSM delivery also. These role guys can work easily for implementing the IT governance in Cloud/DevOps comparatively with other roles.
This is the Stage1 Course Highlight. You will be coached for the concepts of JSON/YAML scripts towards writing the AWS Cloud service components creation. Your personal practice efforts are mandated here.
A detailed Stage2 course discussion video is there in one of the blogs. Follow the below link: https://vskumar.blog/2020/01/20/aws-devops-stage1-stage2-course-for-modern-tech-professional/
Your effort in practicing tools is required here.

Also be aware on the below points [Published in a blog also] :

I feel; For every DevOps Professional learning Infra building activity is mandatory. See the issues, what you are facing within them. Atleast one of them you are facing from your end as mentioned in the below slide/video. Then there is a gap in your implementation practice with lack of learning in a right method with best practices. So think on your actions after the below videos watching!

 You can also see the below blog/videos towards ITSM professionals exp usage for Cloud/DevOps Architect:

https://vskumar.blog/2020/02/15/do-you-want-to-become-cloud-cum-devops-architect-in-one-go/

What IT roles can vanish with Cloud transition ? 

If you are in the below roles, in the current recession you will be targeted for pinkslip among the IT professionals as 1st exit group. What you need to do on your career replan. Please see/follow the blog/videos with patience. 

As per my observation and practice with the trending technology [Cloud], all the Cloud services vendors have inbuilt serverless computing for many services. The following roles are going to be vanished or reskilled. But if they are kept under recession staff cut, these professionals need to take care of their career.

1. DBA:–>The DBA tasks are embedded as part of these services. So the DBAs used to sit hours together in the past to perform many mundane tasks. Now these all are automated.

2. Similarly, many other tasks are related to infra roles; Network admin/Sys-Admin are also automated through Cloud services.

3. As a consolidation all these 3 roles are clubbed into one role of Cloud Engineer. This role’s major task is to automate all the Cloud setup related activities under IAC[Infrastructure As Code]. In future only the IAC will sustain to save the cost to IT by automating the cloud setup creation activity.

4. If any professional need to compete with this role means; they need to understand the Infra needs and the past roles tasks in depth. Along with the multiple Infra related architecture scenarios, with in-depth knowledge on Cloud technology. Then only they can analyze the IAC requirements clearly to write the code and test it. This is the domain analysis and design activity they need to consider apart from the Cloud technology learning.

5. We can also see the Storage engineer role. All the Cloud vendors have the Cloud Storage services. With them mundane tasks creation/maintenance is vanished. Hence this role also will not exist.

IT-infra-Roles
IT-SDLC-Roles

The below video has the discussion on: A) What IT Roles can vanish after migrating to Cloud? B) How the roles/tasks are being transformed to Cloud through serverless computing technology ? C) Why anybody can learn and do the past Infra roles with Cloud ? D) What all they need to learn ? E) How the organizations can demand an employee to convert into modern technology before taking a decision for a pink slip serving ?
Finally, what are the following roles and their tasks:
Traditional Infrastructure building roles:
1.Network Admin/Engineer
2.System Administrator
3.Database Administrator
4. Deployment Engineer

5. Storage Engineer — There is a separate video done for this role education:

Technical Roles:
1.Developer
2.Test Engineer/Analyst

F) Among the above which role can pickup faster the Cloud/DevOps Automation technology ?
G) Then How these roles can perform in Cloud  with faster deployment ?
H) Why and how the manpower reduction happen after Cloud implementation ?

I) Why do you need to learn from the experienced IT mentors to transform into modern technology ?

K) Some people say, they can learn by self. How much they can learn and cope-up with the current market needs on various technologies to settle in modern technology ? [refer to point#5 in this blog].

L) Why do you need to spend/invest  more money to re-settle in the modern technology ?

Note: Along with this video, there are multiple blogs I have published with Videos links to make awareness to the IT Professionals. You see those blogs from this site itself.

For further understanding please read the below text:

In the current IT World Cloud computing became regular practice for any IT Professional. Any cloud services we use, we need to know the current/traditional infrastructure setup. But every IT professional may not have that background/knowledge to understand. Because in this industry each of us played  different roles.

The Infra activities handled IT Professional only will come to know this knowledge and will have experience. But the industry needs every IT employee need to know this knowledge apart from the Cloud service provider [Ex: AWS, Azure, GC, etc..] products operations. [Eventhough, if you are a certified Solutions architect with that Cloud service provider.]

Then only whoever the professionals are certified they will be able to use these products/services and implement them under cloud setup. Hence the Infra domain knowledge or experience is mandated for every IT professional who is working for Cloud services or in that infra setup. I have been hearing during Cloud professionals recruitment the interviewers are keeping some questions on this area also. If one understand the Network domain setup then only they will be able to design the Cloud architecture. Hence more employers are worried to have this domain knowledge with the Certified and recruited Cloud professionals.

I have started a Cloud Practices group to educate/share the IT professionals with this domain knowledge. The below link can be used to join/apply:

https://www.facebook.com/groups/585147288612549/about/

Note:

Cloud: What IT roles can vanish with Cloud transition ?

What IT roles can vanish with Cloud transition ? 

If you are in the below roles, in the current recession you will be targeted for pinkslip among the IT professionals as 1st exit group. What you need to do on your career replan. Please see/follow the blog/videos with patience. 

As per my observation and practice with the trending technology [Cloud], all the Cloud services vendors have inbuilt serverless computing for many services. The following roles are going to be vanished or reskilled. But if they are kept under recession staff cut, these professionals need to take care of their career.

1. DBA:–>The DBA tasks are embedded as part of these services. So the DBAs used to sit hours together in the past to perform many mundane tasks. Now these all are automated.

2. Similarly, many other tasks are related to infra roles; Network admin/Sys-Admin are also automated through Cloud services.

3. As a consolidation all these 3 roles are clubbed into one role of Cloud Engineer. This role’s major task is to automate all the Cloud setup related activities under IAC[Infrastructure As Code]. In future only the IAC will sustain to save the cost to IT by automating the cloud setup creation activity.

4. If any professional need to compete with this role means; they need to understand the Infra needs and the past roles tasks in depth. Along with the multiple Infra related architecture scenarios, with in-depth knowledge on Cloud technology. Then only they can analyze the IAC requirements clearly to write the code and test it. This is the domain analysis and design activity they need to consider apart from the Cloud technology learning.

5. We can also see the Storage engineer role. All the Cloud vendors have the Cloud Storage services. With them mundane tasks creation/maintenance is vanished. Hence this role also will not exist.

IT-infra-Roles

IT-SDLC-Roles

The below video has the discussion on: A) What IT Roles can vanish after migrating to Cloud? B) How the roles/tasks are being transformed to Cloud through serverless computing technology ? C) Why anybody can learn and do the past Infra roles with Cloud ? D) What all they need to learn ? E) How the organizations can demand an employee to convert into modern technology before taking a decision for a pink slip serving ?
Finally, what are the following roles and their tasks:
Traditional Infrastructure building roles:
1.Network Admin/Engineer
2.System Administrator
3.Database Administrator
4. Deployment Engineer

Technical Roles:
1.Developer
2.Test Engineer/Analyst

F) Among the above which role can pickup faster the Cloud/DevOps Automation technology ?
G) Then How these roles can perform in Cloud  with faster deployment ?
H) Why and how the manpower reduction happen after Cloud implementation ?

I) Why do you need to learn from the experienced IT mentors to transform into modern technology ?

K) Some people say, they can learn by self. How much they can learn and cope-up with the current market needs on various technologies to settle in modern technology ? [refer to point#5 in this blog].

L) Why do you need to spend/invest  more money to re-settle in the modern technology ?

Note: Along with this video, there are multiple blogs I have published with Videos links to make awareness to the IT Professionals. You see those blogs from this site itself.

For further understanding please read the below text:

In the current IT World Cloud computing became regular practice for any IT Professional. Any cloud services we use, we need to know the current/traditional infrastructure setup. But every IT professional may not have that background/knowledge to understand. Because in this industry each of us played  different roles.

The Infra activities handled IT Professional only will come to know this knowledge and will have experience. But the industry needs every IT employee need to know this knowledge apart from the Cloud service provider [Ex: AWS, Azure, GC, etc..] products operations. [Eventhough, if you are a certified Solutions architect with that Cloud service provider.]

Then only whoever the professionals are certified they will be able to use these products/services and implement them under cloud setup. Hence the Infra domain knowledge or experience is mandated for every IT professional who is working for Cloud services or in that infra setup. I have been hearing during Cloud professionals recruitment the interviewers are keeping some questions on this area also. If one understand the Network domain setup then only they will be able to design the Cloud architecture. Hence more employers are worried to have this domain knowledge with the Certified and recruited Cloud professionals.

I have started a Cloud Practices group to educate/share the IT professionals with this domain knowledge. The below link can be used to join/apply:

https://www.facebook.com/groups/585147288612549/about/

 

Note:

 

Why do you need to learn from Infra domain knowledge as certified Cloud Professional ?

Benefits of CloudWhy do you need to learn from Infra domain knowledge as certified Cloud Professional ?

 

In the current IT World Cloud computing became regular practice for any IT Professional. Any cloud services we use, we need to know the current/traditional infrastructure setup. But every IT professional may not have that background/knowledge to understand. Because in this industry each of us played  different roles.

The Infra activities handled IT Professional only will come to know this knowledge and will have experience. But the industry needs every IT employee need to know this knowledge apart from the Cloud service provider [Ex: AWS, Azure, GC, etc..] products operations. [Eventhough, if you are a certified Solutions architect with that Cloud service provider.]

Then only whoever the professionals are certified they will be able to use these products/services and implement them under cloud setup. Hence the Infra domain knowledge or experience is mandated for every IT professional who is working for Cloud services or in that infra setup. I have been hearing during Cloud professionals recruitment the interviewers are keeping some questions on this area also. If one understand the Network domain setup then only they will be able to design the Cloud architecture. Hence more employers are worried to have this domain knowledge with the Certified and recruited Cloud professionals.

I have started a Cloud Practices group to educate/share the IT professionals with this domain knowledge. The below link can be used to join/apply:

https://www.facebook.com/groups/585147288612549/about/

Note:

  • I also have special coaching with this domain knowledge coverage using AWS.
  • This kind of coaching you may not find everywhere.
  • Visit the discussion points from the above site to know the level of the coaching.

 

 

Free learning for College passed [this year] out freshers

If you are a College passed out student in this year/latest academic year, you can join the below group:

https://www.facebook.com/groups/817762795246646/?ref=bookmarks

You will be learning the attached imaged contents by self.

These courses are designed as per the current IT industry needs.

Some times there will be free mentoring sessions.

Please read and follow the rules to Join.

For freshers/OPTs: For Agile/DevOps/AWS training contact for schedules

For course:

  1. This is for OPTs and the Indian colleges fresh graduates who came/passed out in 2019.

  2. who are self driven and try for jobs with the given skills learning without getting into somebody shoes, come and get trained. You wouldn’t see the labs as demos. You will be practicing the labs as per the coacher guidelines with his watching. So that you will gain the technical competency with self confidence.

  3. A new batch is planned in a cost effective way. Contact in the given FB links from the blog. Good luck in your job search and in IT profession.

  4. Also, visit the below blogs for  AWS Basic course and the AWS-DevOps: https://vskumar.blog/2019/05/04/for-freshers-opts-for-agile-devops-aws-training-contact-for-schedules/
  5. https://vskumar.blog/2020/08/21/aws-devops-course-for-freshers-with-project-level-tasks/
  6. If you are keen in doing a fast track course to attack the job market instead of learning by self for months together and  getting struck to move forward, you can opt for #4 and #5.  Read the videos descriptions also. The contact details are given on this web page logo.

For specimen sessions you can watch the below videos:

  1. Agile: What are Agile manifesto Principles & How they can be used for SW ?
    https://www.facebook.com/328906801086961/videos/617149372179077/
  2. Agile: What are the phases of Agile Project ?
    https://www.facebook.com/328906801086961/videos/183496779674097/
  3. Agile: What is Disciplined Agile Delivery[DAD] ?
    https://www.facebook.com/328906801086961/videos/184822556096397/
  4. Agile: What is Model Storming ?
    https://www.facebook.com/328906801086961/videos/493982721500147/
  5. Agile: What is Scrum Framework and its roles ?
    https://www.facebook.com/328906801086961/videos/878197645967794/

Free-orientation-for Freshers-2019

Join in the below group to follow the above guidelines:

https://www.facebook.com/groups/817762795246646/

This group is meant only for freshers/OPTs coaching on the topics mentioned in the group Logo. You can forward to your circles who all came out from college for latest passed out year. They need to provide evidences as they are from latest batch only. The FB ID need to have photo with profile details. With these specs only they are allowed in this group.

For course: This is for OPTs and the Indian college graduate who came/passed out in 2019. who are self driven and try for jobs with the given skills learning without getting into somebody shoes, come and get trained. A new batch is planned in a cost effective way. Contact in the given FB links from the blog. Good luck in your job search and in IT profession.

https://www.linkedin.com/jobs/aws-jobs/

You can also see the Basic AWS and DevOps course details from the below blog/videos:

https://vskumar.blog/2020/08/21/aws-devops-course-for-freshers-with-project-level-tasks/

Why do you need to learn from Infra domain knowledge as certified Cloud Professional ?

Benefits of CloudWhy do you need to learn from Infra domain knowledge as certified Cloud Professional ?

In the current IT World Cloud computing became regular practice for any IT Professional. Any cloud services we use, we need to know the current/traditional infrastructure setup. But every IT professional may not have that background/knowledge to understand. Because in this industry each of us played  different roles.

The Infra activities handled IT Professional only will come to know this knowledge and will have experience. But the industry needs every IT employee need to know this knowledge apart from the Cloud service provider [Ex: AWS, Azure, GC, etc..] products operations. [Eventhough, if you are a certified Solutions architect with that Cloud service provider.]

Then only whoever the professionals are certified they will be able to use these products/services and implement them under cloud setup. Hence the Infra domain knowledge or experience is mandated for every IT professional who is working for Cloud services or in that infra setup. I have been hearing during Cloud professionals recruitment the interviewers are keeping some questions on this area also. If one understand the Network domain setup then only they will be able to design the Cloud architecture. Hence more employers are worried to have this domain knowledge with the Certified and recruited Cloud professionals.

Below video has the details of SAA Course with the domain knowledge expertism for you:

https://business.facebook.com/vskumarcloud/videos/642868796242922/

I have started a Cloud Practices group to educate/share the IT professionals with this domain knowledge. The below link can be used to join/apply:

https://www.facebook.com/groups/585147288612549/about/

Visit for free concepts learning:

To join DevOps Practices group visit:

https://www.facebook.com/groups/1911594275816833/about/

To join Cloud Practices group visit:

https://www.facebook.com/groups/585147288612549/about/

Note:

  • I also have special coaching with this domain knowledge coverage using AWS.
  • This kind of coaching you may not find everywhere.
  • Visit the discussion points from the above site to know the level of the coaching.

12. DevOps: How to build docker images using dockerfile ? -1

 

Docker-logo

In continuation of my  previous session on :”11. DevOps: How to Launch a container as a daemon ?”, in this session I would like to demonstrate the exercises on:

“How to build docker images using dockerfile ?:”

These images are basic operating environments, such as ubuntu.
We found these while doing the other lab exercises.
The docker images can craft advanced application stacks for the enterprise and cloud IT environments.
Currently let us craft an image manually by launching a container from a base image.
A best practices is, we can build an automated approach of crafting the images using Dockerfile.
The dockerfile is a a text-based build script which contains special instructions in a sequence for building the correct and the relevant images from the base images.

Please note; we will explore all these combinations in different sessions.

Now, let us understand this automated approach from the below steps:
1. The sequential instructions inside Dockerfile can include selecting the base image as 1st statement.
2. And in the later statements; installing the required application, adding the configuration and the data files, and automatically running the services as well as exposing those services to the external world.

This way the dockerfile based automated build approach has simplified the image building process.

It also offers a great deal of flexibility in organizing the build instructions and in visualizing the complete build process, while running the script instructions.

The Docker Engine tightly integrates this build process with the help of the docker ‘build’ subcommand.

This process involes the below steps:
1. Let us imagine; in the client server scenario of Docker, the Docker server (or daemon) is responsible towards complete build process.
2. And the Docker command-line interface is responsible for transferring the build context, including transferring Dockerfile to the daemon.
Now, let us list our existing images as below, in continuation of previous exercise:
=============>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
busybox latest 6ad733544a63 4 weeks ago 1.13MB
busybox 1.24 47bcc53f74dc 20 months ago 1.11MB
vskumar@ubuntu:~$
====================>
Now,  let us create a simple container from the ubuntu base image.
To create it, we can create ‘dockerfile’ without extension using vi in the current pwd.

Please note we do not have vim utility in this Ubuntu base image.
=================>
vskumar@ubuntu:~$ pwd
/home/vskumar
vskumar@ubuntu:~$ vi dockerfile
============>
Now, let us cat the dockerfile as below:
=============>
vskumar@ubuntu:~$ ls -l
total 48
drwxr-xr-x 3 vskumar vskumar 4096 Nov 24 23:32 Desktop
-rw-rw-r– 1 vskumar vskumar 86 Dec 3 04:29 dockerfile
drwxr-xr-x 2 vskumar vskumar 4096 Nov 22 21:23 Documents
drwxr-xr-x 2 vskumar vskumar 4096 Nov 25 06:33 Downloads
-rw-r–r– 1 vskumar vskumar 8980 Nov 22 21:03 examples.desktop
drwxr-xr-x 2 vskumar vskumar 4096 Nov 22 21:23 Music
drwxr-xr-x 2 vskumar vskumar 4096 Nov 25 06:02 Pictures
drwxr-xr-x 2 vskumar vskumar 4096 Nov 22 21:23 Public
drwxr-xr-x 2 vskumar vskumar 4096 Nov 22 21:23 Templates
drwxr-xr-x 2 vskumar vskumar 4096 Nov 22 21:23 Videos
vskumar@ubuntu:~$
vskumar@ubuntu:~$ cat dockerfile
FROM ubuntu
CMD [“echo”, “This is done by vskumar for a lab practice of dockerfile”]
vskumar@ubuntu:~$
================>
From the above dockerfile contents:
1st line FROM ubuntu – denotes it is using the buntu as the base image to create the container.
2nd line: CMD [“echo”, “This is done by vskumar for a lab practice of dockerfile”]
denotes using CMD echo command is executed to print the message “This is done by vskumar for a lab practice of dockerfile”.
Now let us run this file through the below command:
$ sudo docker build .
We can see the output as below:
===============>
vskumar@ubuntu:~$ sudo docker build .
Sending build context to Docker daemon 112MB
Step 1/2 : FROM ubuntu
—> 20c44cd7596f
Step 2/2 : CMD [“echo”, “This is done by vskumar for a lab practice of dockerfile”]
—> Running in 1de59a4799fa
Removing intermediate container 1de59a4799fa
—> 8de083612fef
Successfully built 8de083612fef
vskumar@ubuntu:~$
===================>
Now, let us list the images:
==================>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
<none> <none> 8de083612fef About a minute ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
busybox latest 6ad733544a63 4 weeks ago 1.13MB
busybox 1.24 47bcc53f74dc 20 months ago 1.11MB
vskumar@ubuntu:~$
==========================>
We can see Imgae id: 8de083612fef is created just now.
Look into that line there is no tag given.
Now let us tag it as below:
$ sudo docker tag 8de083612fef ubuntu-testbox1
================>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ sudo docker tag 8de083612fef ubuntu-testbox1
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-testbox1 latest 8de083612fef 4 minutes ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
busybox latest 6ad733544a63 4 weeks ago 1.13MB
busybox 1.24 47bcc53f74dc 20 months ago 1.11MB
vskumar@ubuntu:~$
====================>
Now, let us do some housekeeping on these containers.
Let us list the containers using ps -a command
====================>
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
0fe495fc93ed ubuntu “/bin/bash -c ‘while…” 8 hours ago Exited (137) 4 hours ago hungry_engelbart
10ffea6140f9 ubuntu “bash” 7 days ago Exited (0) 7 days ago quizzical_lalande
b2a79f8d2fe6 ubuntu “/bin/bash -c ‘while…” 7 days ago Exited (255) 7 days ago goofy_borg
155f4b0764b1 ubuntu:16.04 “/bin/bash” 7 days ago Exited (0) 7 days ago zen_volhard
vskumar@ubuntu:~$
=====================>
I want to remove all of them. We can recreate with the dockerfile as an exercise.
$ Sudo docker containers prune
=======================================>
vskumar@ubuntu:~$ sudo docker ps -aq
0fe495fc93ed
10ffea6140f9
b2a79f8d2fe6
155f4b0764b1
vskumar@ubuntu:~$ sudo docker container prune
WARNING! This will remove all stopped containers.
Are you sure you want to continue? [y/N] y
Deleted Containers:
0fe495fc93edee3aaadc7fc0fbf21997f0ca3cde4d7e563aa8c61352a43957dd
10ffea6140f9c93b37bad2f9d159ad53aa121c0de69a9d145f07cc12f9591324
b2a79f8d2fe65453fce19f00d7adf03ed6dcced69ae68fba94ad0c416545263e
155f4b0764b16f1c8776a101cced6ea95c55eeabe69aeab8520cbe925bedc456

Total reclaimed space: 186B
vskumar@ubuntu:~$ sudo docker ps -aq
vskumar@ubuntu:~$
============== so now there are no containers =========>
Let us build the container.
Before building let us check the available images:
==================>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-testbox1 latest 8de083612fef 24 minutes ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
busybox latest 6ad733544a63 4 weeks ago 1.13MB
busybox 1.24 47bcc53f74dc 20 months ago 1.11MB
vskumar@ubuntu:~$
====================>
Let us remove some more images also.
We need to use the below commands:
=========== Let us try one image removal =========>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-testbox1 latest 8de083612fef 33 minutes ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
busybox latest 6ad733544a63 4 weeks ago 1.13MB
busybox 1.24 47bcc53f74dc 20 months ago 1.11MB
vskumar@ubuntu:~$ sudo docker rmi image 47bcc53f74dc
Untagged: busybox:1.24
Untagged: busybox@sha256:8ea3273d79b47a8b6d018be398c17590a4b5ec604515f416c5b797db9dde3ad8
Deleted: sha256:47bcc53f74dc94b1920f0b34f6036096526296767650f223433fe65c35f149eb
Deleted: sha256:f6075681a244e9df4ab126bce921292673c9f37f71b20f6be1dd3bb99b4fdd72
Deleted: sha256:1834950e52ce4d5a88a1bbd131c537f4d0e56d10ff0dd69e66be3b7dfa9df7e6
Error: No such image: image
vskumar@ubuntu:~$
=================================>
So, by using :
sudo docker rmi image [image id], we can remove the image.

Now, further continuation of our dockerfile exercise;
We can create a container from ubuntu base image and install vim package on it with the help of dockerfile.
To do this we need to have following dockerfile script.
——————>
FROM ubuntu
RUN apt-get update
RUN apt-get -y install vim
CMD [“echo”, “This is done by vskumar for a lab demo on dockerfile”]
—————–>
Before doing it, let me do some housekeeping.
I have removed the below image:
==================>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ sudo docker rmi image 6ad733544a63
Untagged: busybox:latest
Untagged: busybox@sha256:bbc3a03235220b170ba48a157dd097dd1379299370e1ed99ce976df0355d24f0
Deleted: sha256:6ad733544a6317992a6fac4eb19fe1df577d4dec7529efec28a5bd0edad0fd30
Deleted: sha256:0271b8eebde3fa9a6126b1f2335e170f902731ab4942f9f1914e77016540c7bb
Error: No such image: image
=====================>
See the current status:
===================>
vskumar@ubuntu:~$ ls
Desktop dockerfile Documents Downloads examples.desktop Music Pictures Public Templates Videos
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-testbox1 latest 8de083612fef About an hour ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$
======================>
Now let me update the dockerfile through vi and cat that file:
====================>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ pwd
/home/vskumar
vskumar@ubuntu:~$ vi dockerfile
vskumar@ubuntu:~$ cat dockerfile
FROM ubuntu
RUN apt-get update
RUN apt-get -y install vim
CMD [“echo”, “This is done by vskumar for a lab practice of dockerfile”]
vskumar@ubuntu:~$
====================>
Now let me run the below command:
$ sudo docker build -t ubuntu-vmbox .
This time; I have added the tag name as ‘ ubuntu-vmbox’.
We need to understand; there are below tasks it involves:
1. Updating the ubuntu libraries – it takes some time by displaying lot of output.
2. Installing vim utility. — This also takes some time.
3. Displaying the message.
We can see this large size output:
=========== Update the packages and install the vim in a conatiner ==========>
vskumar@ubuntu:~$ pwd
/home/vskumar
vskumar@ubuntu:~$ sudo docker build -t ubuntu-vmbox .
Sending build context to Docker daemon 112MB
Step 1/4 : FROM ubuntu
latest: Pulling from library/ubuntu
Digest: sha256:7c67a2206d3c04703e5c23518707bdd4916c057562dd51c74b99b2ba26af0f79
Status: Downloaded newer image for ubuntu:latest
—> 20c44cd7596f
Step 2/4 : RUN apt-get update
—> Running in df81eaef9437
Get:1 http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get:2 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]
Get:4 http://archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB]
Get:5 http://archive.ubuntu.com/ubuntu xenial/universe Sources [9802 kB]
Get:6 http://security.ubuntu.com/ubuntu xenial-security/universe Sources [53.1 kB]
Get:7 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages [1558 kB]
Get:8 http://archive.ubuntu.com/ubuntu xenial/restricted amd64 Packages [14.1 kB]
Get:9 http://archive.ubuntu.com/ubuntu xenial/universe amd64 Packages [9827 kB]
Get:10 http://archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages [176 kB]
Get:11 http://archive.ubuntu.com/ubuntu xenial-updates/universe Sources [231 kB]
Get:12 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [866 kB]
Get:13 http://archive.ubuntu.com/ubuntu xenial-updates/restricted amd64 Packages [13.7 kB]
Get:14 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [719 kB]
Get:15 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages [18.5 kB]
Get:16 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 Packages [5174 B]
Get:17 http://archive.ubuntu.com/ubuntu xenial-backports/universe amd64 Packages [7150 B]
Get:18 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages [505 kB]
Get:19 http://security.ubuntu.com/ubuntu xenial-security/restricted amd64 Packages [12.9 kB]
Get:20 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 Packages [229 kB]
Get:21 http://security.ubuntu.com/ubuntu xenial-security/multiverse amd64 Packages [3479 B]
Fetched 24.6 MB in 2min 5s (196 kB/s)
Reading package lists…
Removing intermediate container df81eaef9437
—> 13cd766374bc
Step 3/4 : RUN apt-get -y install vim
—> Running in d37783a8cb7d
Reading package lists…
Building dependency tree…
Reading state information…
The following additional packages will be installed:
file libexpat1 libgpm2 libmagic1 libmpdec2 libpython3.5 libpython3.5-minimal
libpython3.5-stdlib libsqlite3-0 libssl1.0.0 mime-support vim-common
vim-runtime
Suggested packages:
gpm ctags vim-doc vim-scripts vim-gnome-py2 | vim-gtk-py2 | vim-gtk3-py2
| vim-athena-py2 | vim-nox-py2
The following NEW packages will be installed:
file libexpat1 libgpm2 libmagic1 libmpdec2 libpython3.5 libpython3.5-minimal
libpython3.5-stdlib libsqlite3-0 libssl1.0.0 mime-support vim vim-common
vim-runtime
0 upgraded, 14 newly installed, 0 to remove and 2 not upgraded.
Need to get 12.2 MB of archives.
After this operation, 58.3 MB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu xenial/main amd64 libgpm2 amd64 1.20.4-6.1 [16.5 kB]
Get:2 http://archive.ubuntu.com/ubuntu xenial/main amd64 libmagic1 amd64 1:5.25-2ubuntu1 [216 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial/main amd64 file amd64 1:5.25-2ubuntu1 [21.2 kB]
Get:4 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libexpat1 amd64 2.1.0-7ubuntu0.16.04.3 [71.2 kB]
Get:5 http://archive.ubuntu.com/ubuntu xenial/main amd64 libmpdec2 amd64 2.4.2-1 [82.6 kB]
Get:6 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libssl1.0.0 amd64 1.0.2g-1ubuntu4.9 [1085 kB]
Get:7 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libpython3.5-minimal amd64 3.5.2-2ubuntu0~16.04.4 [523 kB]
Get:8 http://archive.ubuntu.com/ubuntu xenial/main amd64 mime-support all 3.59ubuntu1 [31.0 kB]
Get:9 http://archive.ubuntu.com/ubuntu xenial/main amd64 libsqlite3-0 amd64 3.11.0-1ubuntu1 [396 kB]
Get:10 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libpython3.5-stdlib amd64 3.5.2-2ubuntu0~16.04.4 [2132 kB]
Get:11 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 vim-common amd64 2:7.4.1689-3ubuntu1.2 [103 kB]
Get:12 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libpython3.5 amd64 3.5.2-2ubuntu0~16.04.4 [1360 kB]
Get:13 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 vim-runtime all 2:7.4.1689-3ubuntu1.2 [5164 kB]
Get:14 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 vim amd64 2:7.4.1689-3ubuntu1.2 [1036 kB]
debconf: delaying package configuration, since apt-utils is not installed
Fetched 12.2 MB in 12s (949 kB/s)
Selecting previously unselected package libgpm2:amd64.
(Reading database … 4768 files and directories currently installed.)
Preparing to unpack …/libgpm2_1.20.4-6.1_amd64.deb …
Unpacking libgpm2:amd64 (1.20.4-6.1) …
Selecting previously unselected package libmagic1:amd64.
Preparing to unpack …/libmagic1_1%3a5.25-2ubuntu1_amd64.deb …
Unpacking libmagic1:amd64 (1:5.25-2ubuntu1) …
Selecting previously unselected package file.
Preparing to unpack …/file_1%3a5.25-2ubuntu1_amd64.deb …
Unpacking file (1:5.25-2ubuntu1) …
Selecting previously unselected package libexpat1:amd64.
Preparing to unpack …/libexpat1_2.1.0-7ubuntu0.16.04.3_amd64.deb …
Unpacking libexpat1:amd64 (2.1.0-7ubuntu0.16.04.3) …
Selecting previously unselected package libmpdec2:amd64.
Preparing to unpack …/libmpdec2_2.4.2-1_amd64.deb …
Unpacking libmpdec2:amd64 (2.4.2-1) …
Selecting previously unselected package libssl1.0.0:amd64.
Preparing to unpack …/libssl1.0.0_1.0.2g-1ubuntu4.9_amd64.deb …
Unpacking libssl1.0.0:amd64 (1.0.2g-1ubuntu4.9) …
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Preparing to unpack …/libpython3.5-minimal_3.5.2-2ubuntu0~16.04.4_amd64.deb …
Unpacking libpython3.5-minimal:amd64 (3.5.2-2ubuntu0~16.04.4) …
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Unpacking mime-support (3.59ubuntu1) …
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Unpacking libsqlite3-0:amd64 (3.11.0-1ubuntu1) …
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Preparing to unpack …/libpython3.5-stdlib_3.5.2-2ubuntu0~16.04.4_amd64.deb …
Unpacking libpython3.5-stdlib:amd64 (3.5.2-2ubuntu0~16.04.4) …
Selecting previously unselected package vim-common.
Preparing to unpack …/vim-common_2%3a7.4.1689-3ubuntu1.2_amd64.deb …
Unpacking vim-common (2:7.4.1689-3ubuntu1.2) …
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Unpacking libpython3.5:amd64 (3.5.2-2ubuntu0~16.04.4) …
Selecting previously unselected package vim-runtime.
Preparing to unpack …/vim-runtime_2%3a7.4.1689-3ubuntu1.2_all.deb …
Adding ‘diversion of /usr/share/vim/vim74/doc/help.txt to /usr/share/vim/vim74/doc/help.txt.vim-tiny by vim-runtime’
Adding ‘diversion of /usr/share/vim/vim74/doc/tags to /usr/share/vim/vim74/doc/tags.vim-tiny by vim-runtime’
Unpacking vim-runtime (2:7.4.1689-3ubuntu1.2) …
Selecting previously unselected package vim.
Preparing to unpack …/vim_2%3a7.4.1689-3ubuntu1.2_amd64.deb …
Unpacking vim (2:7.4.1689-3ubuntu1.2) …
Processing triggers for libc-bin (2.23-0ubuntu9) …
Setting up libgpm2:amd64 (1.20.4-6.1) …
Setting up libmagic1:amd64 (1:5.25-2ubuntu1) …
Setting up file (1:5.25-2ubuntu1) …
Setting up libexpat1:amd64 (2.1.0-7ubuntu0.16.04.3) …
Setting up libmpdec2:amd64 (2.4.2-1) …
Setting up libssl1.0.0:amd64 (1.0.2g-1ubuntu4.9) …
debconf: unable to initialize frontend: Dialog
debconf: (TERM is not set, so the dialog frontend is not usable.)
debconf: falling back to frontend: Readline
debconf: unable to initialize frontend: Readline
debconf: (Can’t locate Term/ReadLine.pm in @INC (you may need to install the Term::ReadLine module) (@INC contains: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.22.1 /usr/local/share/perl/5.22.1 /usr/lib/x86_64-linux-gnu/perl5/5.22 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.22 /usr/share/perl/5.22 /usr/local/lib/site_perl /usr/lib/x86_64-linux-gnu/perl-base .) at /usr/share/perl5/Debconf/FrontEnd/Readline.pm line 7.)
debconf: falling back to frontend: Teletype
Setting up libpython3.5-minimal:amd64 (3.5.2-2ubuntu0~16.04.4) …
Setting up mime-support (3.59ubuntu1) …
Setting up libsqlite3-0:amd64 (3.11.0-1ubuntu1) …
Setting up libpython3.5-stdlib:amd64 (3.5.2-2ubuntu0~16.04.4) …
Setting up vim-common (2:7.4.1689-3ubuntu1.2) …
Setting up libpython3.5:amd64 (3.5.2-2ubuntu0~16.04.4) …
Setting up vim-runtime (2:7.4.1689-3ubuntu1.2) …
Setting up vim (2:7.4.1689-3ubuntu1.2) …
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/vim (vim) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/vimdiff (vimdiff) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/rvim (rvim) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/rview (rview) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/vi (vi) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/view (view) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/ex (ex) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/editor (editor) in auto mode
Processing triggers for libc-bin (2.23-0ubuntu9) …
Removing intermediate container d37783a8cb7d
—> c07c6f2d2c65
Step 4/4 : CMD [“echo”, “This is done by vskumar for a lab practice of dockerfile”]
—> Running in f7e85f87b578
Removing intermediate container f7e85f87b578
—> f6675f4738b7
Successfully built f6675f4738b7
Successfully tagged ubuntu-vmbox:latest
vskumar@ubuntu:~$
=== Finally you can see the ‘ubuntu-vmbox’ tagged conatiner ======>
We can see the latest image from the below images:
===== Current images list =====>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 3 minutes ago 220MB
ubuntu-testbox1 latest 8de083612fef About an hour ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$
=======================>
Now, I want to work with this newly created container. Please recollect my blog “https://vskumar.blog/2017/11/29/6-devops-how-to-work-with-interactive-docker-containers/”.
As we did practice in it; we can use the below command to work with this new container:

sudo docker run -i -t ubuntu-vmbox /bin/bash
I want to test the vim is working on it. See the below output:
==================>
vskumar@ubuntu:~$ sudo docker run -i -t ubuntu-vmbox /bin/bash

root@1169bb1285cf:/#
root@1169bb1285cf:/# pwd
/
root@1169bb1285cf:/# ls
bin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var
root@1169bb1285cf:/# vim test1
===== I have created the file with vim successfully ====>
Now let me use cat command and see its output:

================>
root@1169bb1285cf:/#
root@1169bb1285cf:/# ls
bin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys test1 tmp usr var
root@1169bb1285cf:/# cat test1
testing this vim box……
root@1169bb1285cf:/#
=================>

So, in this exercise we have updated the ubuntu libraries and installed vim utility.
And tested the container for vim usage by using interactive mode.

=========== Now let me exit and check the list of images =====>
root@1169bb1285cf:/#
root@1169bb1285cf:/# exit
exit
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 13 minutes ago 220MB
ubuntu-testbox1 latest 8de083612fef About an hour ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$
=============================>
So, the new container ‘ubuntu-vmbox’ is existing.

Now, I want to remove some images:
sudo docker rmi 20c44cd7596f
================>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 18 minutes ago 220MB
ubuntu-testbox1 latest 8de083612fef About an hour ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$ sudo docker rmi 20c44cd7596f
Error response from daemon: conflict: unable to delete 20c44cd7596f (cannot be forced) – image has dependent child images
vskumar@ubuntu:~$
== Please note the last image was the base to build the top tow containers ===>
Hence it has the child and parent relationship.
First we need to remove the child images and later the parent need to be removed.
=== You can see the removal of child one and one more image=====>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 20 minutes ago 220MB
ubuntu-testbox1 latest 8de083612fef 2 hours ago 123MB
docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$ sudo docker rmi 8de083612fef
Untagged: ubuntu-testbox1:latest
Deleted: sha256:8de083612fefbf9723913748f7db4aba4154b17adc500d011f44df356736f06c
vskumar@ubuntu:~$ sudo docker rmi e34304119838
Untagged: docker-exercise/ubuntu-wgetinstall:latest
Deleted: sha256:e34304119838d79da60e12776529106c350b1972cd517648e8ab90311fad7b1a
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 21 minutes ago 220MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$
=================>
Let me do some more exercises on housekeeping.
I would like to present some more dependency issues for the above images. You can clearly see the output:
========= Dependencies =======>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 22 minutes ago 220MB
<none> <none> fc7e4564eb92 7 days ago 169MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$ sudo docker rmi fc7e4564eb92
Deleted: sha256:fc7e4564eb928ccfe068c789f0d650967e8d5dc42d4e8d92409aab6614364075
Deleted: sha256:b16d78406b12e6dbc174f4e71bedb7b9edc0593cad10458ddf042738694c06db
vskumar@ubuntu:~$ sudo docker rmi 20c44cd7596f
Error response from daemon: conflict: unable to delete 20c44cd7596f (cannot be forced) – image has dependent child images
vskumar@ubuntu:~$ sudo docker rmi f6675f4738b7
Error response from daemon: conflict: unable to delete f6675f4738b7 (must be forced) – image is being used by stopped container 1169bb1285cf
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
1169bb1285cf ubuntu-vmbox “/bin/bash” 15 minutes ago Exited (0) 11 minutes ago heuristic_mayer
vskumar@ubuntu:~$
====================>
It means the container “1169bb1285cf ubuntu-vmbox” is the child to image id:f6675f4738b7.
===========>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 27 minutes ago 220MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
1169bb1285cf ubuntu-vmbox “/bin/bash” 19 minutes ago Exited (0) 14 minutes ago heuristic_mayer
vskumar@ubuntu:~$
==============>
So if I want to remove Image id: f6675f4738b7, I need to remove the container id:1169bb1285cf , and later I need to remove this image.
$ sudo docker rm container 1169bb1285cf
And later image removal command need to be used as below.
======================>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-vmbox latest f6675f4738b7 31 minutes ago 220MB
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$ sudo docker rmi f6675f4738b7
Untagged: ubuntu-vmbox:latest
Deleted: sha256:f6675f4738b721780721f345906a0c78c13a67ee8239a16f071504b217f41658
Deleted: sha256:c07c6f2d2c651dd406977d42d5504c941d7f975a84c8547abaf3869b50942820
Deleted: sha256:4855cfb7ae6f84279bbbfe87e7691377531a541785c613014f64909e6e0f4528
Deleted: sha256:13cd766374bcb31cc0e8cac971e82754bb8e1bc66780abaff264f847e00a94b2
Deleted: sha256:dc6fab8a33a18a8c840e19612253657c4610ab865a26de5a31260f71bcef5f76
vskumar@ubuntu:~$
========================>
So we have the below images only now:
==== Current images ======>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$
==========================>
We can try to remove the above images:
========= See it is declined due to it is base image ===========>
vskumar@ubuntu:~$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest f2a91732366c 12 days ago 1.85kB
ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB
ubuntu latest 20c44cd7596f 2 weeks ago 123MB
vskumar@ubuntu:~$ sudo docker rmi 20c44cd7596f
Error response from daemon: conflict: unable to delete 20c44cd7596f (must be forced) – image is referenced in multiple repositories
vskumar@ubuntu:~$
=========================>
Both ubuntu images are interlinked and they can not be removed as the base docker engine is working on top of their OS.

We will stop this session at this time.

We will continue some more sessions on “dockerfile”.

 

Vcard-Shanthi Kumar V-v3

11. DevOps: How to Launch a container as a daemon ?

Docker-logo

In continuation of my previous blog on “10. DevOps: How to Build images from Docker containers?”, I am continuing my lab exercises. In this session we can see ”

How to Launch a container as a daemon ?:

Note: If you want to recollect the docker commands to be used during your current lab practice, visit my blog link:

https://vskumarblogs.wordpress.com/2017/12/13/some-useful-docker-commands-for-handling-images-and-containers/

 

Let us recap the past exercises; So far we have experimented with an interactive container, tracked the changes that were made to the containers., created images from the containers, and then gained insights in the containerization scenarios.

Now, let us see the container usage in a detached mode.

When we run the container in a detached mode it runs under a daemon process.

I want to use the “ubuntu” image and run detached mode command.

First, let me check my current docker images:

==================>

vskumar@ubuntu:~$

vskumar@ubuntu:~$ sudo docker images

[sudo] password for vskumar:

REPOSITORY TAG IMAGE ID CREATED SIZE

docker-exercise/ubuntu-wgetinstall latest e34304119838 7 days ago 169MB

<none> <none> fc7e4564eb92 7 days ago 169MB

hello-world latest f2a91732366c 12 days ago 1.85kB

ubuntu 16.04 20c44cd7596f 2 weeks ago 123MB

ubuntu latest 20c44cd7596f 2 weeks ago 123MB

busybox latest 6ad733544a63 4 weeks ago 1.13MB

busybox 1.24 47bcc53f74dc 20 months ago 1.11MB

vskumar@ubuntu:~$

===================>

You can see my previous image with ‘docker-exercise/ubuntu-wgetinstall ‘. This was created in the previous exercise.

As per our plan in this session I am using the below commands to run the ubuntu image as below:

sudo docker run -d ubuntu \

    /bin/bash -c "while true; do date; sleep 5; done";

========== Output ======>
vskumar@ubuntu:~$  sudo docker run -d ubuntu \
>     /bin/bash -c "while true; do date; sleep 5; done";
0fe495fc93edee3aaadc7fc0fbf21997f0ca3cde4d7e563aa8c61352a43957dd
vskumar@ubuntu:~$ $ 
=======================>

Now, to view the docker logs I want to run the docker logs subcommand on image id: ‘ 0fe495fc93edee3aaadc7fc0fbf21997f0ca3cde4d7e563aa8c61352a43957dd’

$ sudo docker logs 0fe495fc93edee3aaadc7fc0fbf21997f0ca3cde4d7e563aa8c61352a43957dd;

=====See the output of the Daemon process running with the ubuntu image ===============>

vskumar@ubuntu:~$ sudo docker logs 0fe495fc93edee3aaadc7fc0fbf21997f0ca3cde4d7e563aa8c61352a43957dd;

Sun Dec 3 05:11:57 UTC 2017

Sun Dec 3 05:12:02 UTC 2017

Sun Dec 3 05:12:07 UTC 2017

Sun Dec 3 05:12:12 UTC 2017

Sun Dec 3 05:12:17 UTC 2017

Sun Dec 3 05:12:22 UTC 2017

Sun Dec 3 05:12:27 UTC 2017

Sun Dec 3 05:12:32 UTC 2017

Sun Dec 3 05:12:37 UTC 2017

Sun Dec 3 05:12:42 UTC 2017

Sun Dec 3 05:12:48 UTC 2017

Sun Dec 3 05:12:53 UTC 2017

Sun Dec 3 05:12:58 UTC 2017

Sun Dec 3 05:13:03 UTC 2017

Sun Dec 3 05:13:08 UTC 2017

Sun Dec 3 05:13:13 UTC 2017

Sun Dec 3 05:13:18 UTC 2017

Sun Dec 3 05:13:23 UTC 2017

Sun Dec 3 05:13:28 UTC 2017

Sun Dec 3 05:13:33 UTC 2017

Sun Dec 3 05:13:38 UTC 2017

Sun Dec 3 05:13:43 UTC 2017

Sun Dec 3 05:13:48 UTC 2017

Sun Dec 3 05:13:53 UTC 2017

Sun Dec 3 05:13:58 UTC 2017

Sun Dec 3 05:14:03 UTC 2017

Sun Dec 3 05:14:08 UTC 2017

Sun Dec 3 05:14:13 UTC 2017

Sun Dec 3 05:14:18 UTC 2017

Sun Dec 3 05:14:23 UTC 2017

Sun Dec 3 05:14:28 UTC 2017

Sun Dec 3 05:14:33 UTC 2017

Sun Dec 3 05:14:38 UTC 2017

Sun Dec 3 05:14:43 UTC 2017

Sun Dec 3 05:14:48 UTC 2017

Sun Dec 3 05:14:53 UTC 2017

Sun Dec 3 05:14:58 UTC 2017

Sun Dec 3 05:15:03 UTC 2017

Sun Dec 3 05:15:08 UTC 2017

Sun Dec 3 05:15:13 UTC 2017

Sun Dec 3 05:15:18 UTC 2017

Sun Dec 3 05:15:23 UTC 2017

vskumar@ubuntu:~$

=================You can see the output for every few seconds listed =======>

It means the container is running as a daemon.

Now, let us use ps -eaf command to check the processed running in linux by using :

$ ps -eaf | grep ‘daemon’

========= See the output of daemon processes ==========>

vskumar@ubuntu:~$

vskumar@ubuntu:~$ ps -eaf | grep ‘daemon’

message+ 837 1 0 20:26 ? 00:00:05 /usr/bin/dbus-daemon –system –address=systemd: –nofork –nopidfile –systemd-activation

root 871 1 0 20:26 ? 00:00:03 /usr/sbin/NetworkManager –no-daemon

avahi 873 1 0 20:26 ? 00:00:00 avahi-daemon: running [ubuntu.local]

root 876 1 0 20:26 ? 00:00:01 /usr/lib/accountsservice/accounts-daemon

avahi 893 873 0 20:26 ? 00:00:00 avahi-daemon: chroot helper

rtkit 1370 1 0 20:28 ? 00:00:00 /usr/lib/rtkit/rtkit-daemon

vskumar 2426 1 0 20:55 ? 00:00:00 /usr/bin/gnome-keyring-daemon –daemonize –login

vskumar 2508 2428 0 20:55 ? 00:00:00 upstart-udev-bridge –daemon –user

vskumar 2515 2428 0 20:55 ? 00:00:04 dbus-daemon –fork –session –address=unix:abstract=/tmp/dbus-nPaV5rWlQc

vskumar 2570 2428 0 20:55 ? 00:00:03 /usr/lib/x86_64-linux-gnu/bamf/bamfdaemon

vskumar 2572 2428 0 20:55 ? 00:00:04 /usr/bin/ibus-daemon –daemonize –xim –address unix:tmpdir=/tmp/ibus

vskumar 2575 2428 0 20:55 ? 00:00:00 upstart-file-bridge –daemon –user

vskumar 2579 2428 0 20:55 ? 00:00:00 upstart-dbus-bridge –daemon –system –user –bus-name system

vskumar 2582 2428 0 20:55 ? 00:00:00 upstart-dbus-bridge –daemon –session –user –bus-name session

vskumar 2605 2428 0 20:55 ? 00:00:00 /usr/lib/ibus/ibus-x11 –kill-daemon

vskumar 2630 2428 0 20:56 ? 00:00:00 gpg-agent –homedir /home/vskumar/.gnupg –use-standard-socket –daemon

vskumar 2645 2428 0 20:56 ? 00:00:02 /usr/lib/unity-settings-daemon/unity-settings-daemon

vskumar 2664 2653 0 20:56 ? 00:00:00 /usr/bin/dbus-daemon –config-file=/etc/at-spi2/accessibility.conf –nofork –print-address 3

vskumar 2851 2654 0 20:56 ? 00:00:01 /usr/lib/unity-settings-daemon/unity-fallback-mount-helper

vskumar 2914 2428 0 20:57 ? 00:00:00 /bin/sh -c /usr/lib/x86_64-linux-gnu/zeitgeist/zeitgeist-maybe-vacuum; /usr/bin/zeitgeist-daemon

vskumar 2920 2914 0 20:57 ? 00:00:00 /usr/bin/zeitgeist-daemon

vskumar 3094 2428 0 21:00 ? 00:00:01 /usr/lib/x86_64-linux-gnu/unity-lens-files/unity-files-daemon

root 4148 1253 0 21:11 ? 00:00:00 docker-containerd-shim –namespace moby –workdir /var/lib/docker/containerd/daemon/io.containerd.runtime.v1.linux/moby/0fe495fc93edee3aaadc7fc0fbf21997f0ca3cde4d7e563aa8c61352a43957dd –address /var/run/docker/containerd/docker-containerd.sock –runtime-root /var/run/docker/runtime-runc

vskumar 4480 3206 0 21:19 pts/19 00:00:00 grep –color=auto daemon

vskumar@ubuntu:~$

======== You can see the list of processes running currently ========>

So we are successful! to run a container in a detached mode [not in an interactive mode!] using the command: ‘ sudo docker run -d ubuntu’

You can think in an application architecture having multiple servers or SOA running with different services.

You can simulate the same services using the docker containers, by setting up as images by configuring the required services and connect them to the architecture.

This way the advantages of containers can be utilized well. Where different companies are using and implementing their applications into containers architecture by saving lot of infrastructure cost. No hardware or physical servers are required. Lot of space also can be saved. The microservices architecture leads to the same way.

At this point, I would like to stop this session and in the next blog we will see other exercises.

Vcard-Shanthi Kumar V-v3

 

 

9. DevOps: How to do Containers housekeeping ?

Docker-logo

In  continuation of my previous blog on “8. DevOps:How to control and operate docker containers”, in this blog I would like to show some lab practice on “docker Containers housekeeping”.

From the previous lab sessions, we have seen many containers when we used ps -a option.

We have used two containers most of the times.

Others are not required. This time we will see how to remove a container physically.

Let us consider the below containers to remove using rm command:

32bc16b508d4        ubuntu 
a744246ffb8e        hello-world
1dd55efde43f        hello-world

$sudo docker rm 1dd55efde43f 
$sudo docker rm a744246ffb8e 
$sudo docker rm 32bc16b508d4 
================ You can see the above three containers are removed =========>
vskumar@ubuntu:~$ sudo docker rm 1dd55efde43f 
1dd55efde43f
vskumar@ubuntu:~$ sudo docker rm a744246ffb8e 
a744246ffb8e
vskumar@ubuntu:~$ sudo docker rm 32bc16b508d4 
32bc16b508d4
vskumar@ubuntu:~$ sudo docker ps -a |more
CONTAINER ID        IMAGE               COMMAND                 CREATED         
    STATUS                         PORTS               NAMES
f123dbd09116        ubuntu:16.04        "/bin/bash"             18 minutes ago  
    Exited (0) 18 minutes ago                          elastic_nightingale
3cfdea29ce6e        ubuntu              "bash"                  27 minutes ago  
    Exited (0) 26 minutes ago                          gallant_nobel
155f4b0764b1        ubuntu:16.04        "/bin/bash"             About an hour ag
o   Exited (0) 12 minutes ago                          zen_volhard
11e293722c64        ubuntu:16.04        "/bin/bash"             About an hour ag
o   Exited (0) About an hour ago                       dreamy_bassi
d10ad2bd62f7        ubuntu:16.04        "/bin/bash"             About an hour ag
o   Exited (0) About an hour ago                       cranky_dijkstra
cb1ff260d48e        ubuntu              "ls /usr/src"           11 hours ago    
    Exited (0) 11 hours ago                            wonderful_hawking
b20691fd8fb5        ubuntu              "ls /usr"               11 hours ago    
    Exited (0) 11 hours ago                            friendly_mirzakhani
431ba4c53028        ubuntu              "ls"                    11 hours ago    
    Exited (0) 28 minutes ago                          affectionate_nobel
2c31684bb1f4        ubuntu              "ls -la"                11 hours ago    
    Exited (0) 11 hours ago                            zealous_meitner
fe2e3b449daf        ubuntu              "ls -la /home/."        11 hours ago    
    Exited (0) 11 hours ago                            dreamy_shirley
c44bdd05b94d        ubuntu              "ls -la home."          11 hours ago    
    Exited (2) 11 hours ago                            elastic_pasteur
8b8afa82859a        ubuntu              "ls -la"                11 hours ago    
    Exited (0) 11 hours ago                            festive_panini
2811eb37af61        ubuntu              "ls -la 604831dbce2a"   11 hours ago    
    Exited (2) 11 hours ago                            jolly_swartz
604831dbce2a        ubuntu:16.04        "/bin/bash"             11 hours ago    
    Exited (0) 11 hours ago                            vibrant_ride
718636415a7f        ubuntu:16.04        "/bin/bash"             12 hours ago    
    Exited (0) 12 hours ago                            reverent_noyce
53a7751d4673        ubuntu:16.04        "/bin/bash"             13 hours ago    
    Exited (0) 13 hours ago                            musing_chandrasekhar
1ba71598b7b8        hello-world         "/hello"                16 hours ago    
    Exited (0) 16 hours ago                            musing_kare
vskumar@ubuntu:~$  
==============>
Now let us consider some more examples  as below:
3cfdea29ce6e        ubuntu 
cb1ff260d48e        ubuntu 
b20691fd8fb5        ubuntu 
431ba4c53028        ubuntu 
c31684bb1f4        ubuntu 
2c31684bb1f4        ubuntu 
fe2e3b449daf        ubuntu
c44bdd05b94d        ubuntu 
2811eb37af61        ubuntu
Now, let us use the below rm commands:
$sudo docker rm 3cfdea29ce6e
$sudo docker rm cb1ff260d48e
$sudo docker rm b20691fd8fb5 
$sudo docker rm 431ba4c53028 
$sudo docker rm 2c31684bb1f4
$sudo docker rm fe2e3b449daf 
$sudo docker rm c44bdd05b94d
$sudo docker rm 2811eb37af61
=================>
See the below output also:
 ================== Container removal ==========>
vskumar@ubuntu:~$ clear

vskumar@ubuntu:~$ sudo docker rm 3cfdea29ce6e
3cfdea29ce6e
vskumar@ubuntu:~$ sudo docker rm cb1ff260d48e
cb1ff260d48e
vskumar@ubuntu:~$ sudo docker rm b20691fd8fb5
b20691fd8fb5
vskumar@ubuntu:~$ sudo docker rm 431ba4c53028
431ba4c53028
vskumar@ubuntu:~$ sudo docker rm 2c31684bb1f4
2c31684bb1f4
vskumar@ubuntu:~$ sudo docker rm fe2e3b449daf
fe2e3b449daf
vskumar@ubuntu:~$ sudo docker rm fc44bdd05b94d
Error: No such container: fc44bdd05b94d
vskumar@ubuntu:~$ sudo docker rm c44bdd05b94d
c44bdd05b94d
vskumar@ubuntu:~$ sudo docker rm 2811eb37af61
2811eb37af61
vskumar@ubuntu:~$ 
==========================>
Now we can see the list of available containers:
============= List of latest containers ==============>
vskumar@ubuntu:~$ sudo docker ps -a |more
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                         PORTS               NAMES
f123dbd09116        ubuntu:16.04        "/bin/bash"         28 minutes ago      Exited (0) 28 minutes ago                          elastic_nigh
tingale
155f4b0764b1        ubuntu:16.04        "/bin/bash"         About an hour ago   Exited (0) 22 minutes ago                          zen_volhard
11e293722c64        ubuntu:16.04        "/bin/bash"         About an hour ago   Exited (0) About an hour ago                       dreamy_bassi
d10ad2bd62f7        ubuntu:16.04        "/bin/bash"         2 hours ago         Exited (0) About an hour ago                       cranky_dijks
tra
8b8afa82859a        ubuntu              "ls -la"            11 hours ago        Exited (0) 11 hours ago                            festive_pani
ni
604831dbce2a        ubuntu:16.04        "/bin/bash"         12 hours ago        Exited (0) 11 hours ago                            vibrant_ride
718636415a7f        ubuntu:16.04        "/bin/bash"         12 hours ago        Exited (0) 12 hours ago                            reverent_noy
ce
53a7751d4673        ubuntu:16.04        "/bin/bash"         13 hours ago        Exited (0) 13 hours ago                            musing_chand
rasekhar
1ba71598b7b8        hello-world         "/hello"            16 hours ago        Exited (0) 16 hours ago                            musing_kare
vskumar@ubuntu:~$ 
===========================>
Now, I wan to keep very few containers only and remove the below containers:

604831dbce2a        ubuntu:16.04
718636415a7f        ubuntu:16.04 
53a7751d4673        ubuntu:16.04
8b8afa82859a        ubuntu 
I want to use the below  commands to remove  the above containers:
$sudo docker rm 604831dbce2a
$sudo docker rm 718636415a7f
$sudo docker rm 53a7751d4673
$sudo docker rm 8b8afa82859a

========================= We can see the latest/limited containers =======>
vskumar@ubuntu:~$ sudo docker rm 604831dbce2a
604831dbce2a
vskumar@ubuntu:~$ sudo docker rm 718636415a7f
718636415a7f
vskumar@ubuntu:~$ sudo docker rm 53a7751d4673
53a7751d4673
vskumar@ubuntu:~$ sudo docker rm 8b8afa82859a
8b8afa82859a
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                         PORTS               NAMES
f123dbd09116        ubuntu:16.04        "/bin/bash"         36 minutes ago      Exited (0) 36 minutes ago                          elastic_nightingale
155f4b0764b1        ubuntu:16.04        "/bin/bash"         About an hour ago   Exited (0) 30 minutes ago                          zen_volhard
11e293722c64        ubuntu:16.04        "/bin/bash"         About an hour ago   Exited (0) About an hour ago                       dreamy_bassi
d10ad2bd62f7        ubuntu:16.04        "/bin/bash"         2 hours ago         Exited (0) About an hour ago                       cranky_dijkstra
1ba71598b7b8        hello-world         "/hello"            16 hours ago        Exited (0) 16 hours ago                            musing_kare
vskumar@ubuntu:~$ sudo docker ps 
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
vskumar@ubuntu:~$ 
================================>
We can also see the current container ids as below:
========== Listing containers ids ===============>
vskumar@ubuntu:~$ sudo docker ps -aq
f123dbd09116
155f4b0764b1
11e293722c64
d10ad2bd62f7
1ba71598b7b8
vskumar@ubuntu:~$ 
===============================>
To remove the inactive containers there is a prune command. Let us try with it.
Before doing it I want to make a container active and try this prune command on it:
================= I have made one container Active ======>
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                         PORTS               NAMES
f123dbd09116        ubuntu:16.04        "/bin/bash"         About an hour ago   Exited (0) About an hour ago                       elastic_nightingale
155f4b0764b1        ubuntu:16.04        "/bin/bash"         2 hours ago         Exited (0) 40 minutes ago                          zen_volhard
11e293722c64        ubuntu:16.04        "/bin/bash"         2 hours ago         Exited (0) 2 hours ago                             dreamy_bassi
d10ad2bd62f7        ubuntu:16.04        "/bin/bash"         2 hours ago         Exited (0) 2 hours ago                             cranky_dijkstra
1ba71598b7b8        hello-world         "/hello"            17 hours ago        Exited (0) 17 hours ago                            musing_kare
vskumar@ubuntu:~$ sudo docker start 155f4b0764b1
155f4b0764b1
vskumar@ubuntu:~$ sudo docker ps 
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         2 hours ago         Up 6 seconds                            zen_volhard
vskumar@ubuntu:~$ 
========================>
To use prune , below format should be used:
$ sudo docker container prune
=========== The usage of prune command =======>
vskumar@ubuntu:~$ 
vskumar@ubuntu:~$ sudo docker container prune
WARNING! This will remove all stopped containers.
Are you sure you want to continue? [y/N] y
Deleted Containers:
f123dbd09116561a042e12060f449daa9a36d9a59034b1dd1b96846e66ead14d
11e293722c646a0def7a8a1f2cdf85a47654eb62ef7701bd2d7221c7e69a943f
d10ad2bd62f7a8de379272f21dfccec89c0e5829b3a58ce01927530b6b44ea01
1ba71598b7b8d97fcbd3a589a6665238690be99936b6782647b5040eeb82aafa
Total reclaimed space: 844B
vskumar@ubuntu:~$ 
========== You can see the removed container ids =============>
You can see the existing  containers:
====== Available containers after Housekeeping is done =========>
vskumar@ubuntu:~$ 
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         2 hours ago         Up 6 minutes                            zen_volhard
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         2 hours ago         Up 6 minutes                            zen_volhard
vskumar@ubuntu:~$ sudo docker ps -aq
155f4b0764b1
vskumar@ubuntu:~$
===================>
In this exercise we have seen the housekeeping of containers well.
Please note if you have deleted all the containers by mistake, you need to install the containers again. 
Follow the containers creation exercise.

I would like to break this session at this point. In the next blog I would like to present the lab practice on:

 “How to Build images from Docker containers?

Vcard-Shanthi Kumar V


					

8. DevOps:How to control and operate docker containers

Docker-logo

In  continuation of my previous blog on “7. DevOps: How to track changes in a container”, in this blog I would like to show some lab practice “How to control and operate docker containers”.

Controlling/operating Docker container:

In this exercise initially, we can see on how to start/stop/restart the containers.

The Docker Engine enables us to start, stop, and restart a container with a set of docker subcommands.

Let me display the docker images:

=======================>

vskumar@ubuntu:~$ sudo service docker status

docker.service – Docker Application Container Engine

Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: e

Active: active (running) since Sat 2017-11-25 15:09:35 PST; 2min 24s ago

Docs: https://docs.docker.com

Main PID: 1356 (dockerd)

Tasks: 30

Memory: 95.2M

CPU: 3.998s

=========================>

vskumar@ubuntu:~$ sudo docker images

REPOSITORY TAG IMAGE ID CREATED SIZE

hello-world latest f2a91732366c 4 days ago 1.85kB

ubuntu 16.04 20c44cd7596f 8 days ago 123MB

ubuntu latest 20c44cd7596f 8 days ago 123MB

busybox latest 6ad733544a63 3 weeks ago 1.13MB

busybox 1.24 47bcc53f74dc 20 months ago 1.11MB

vskumar@ubuntu:~$

=======================>

Now, I want to launch our container ubuntu 16.04 with start subcommand and experiment with the docker stop subcommand, as given below:

$ sudo docker run -i -t ubuntu:16.04 /bin/bash

======================>
vskumar@ubuntu:~$ 
vskumar@ubuntu:~$ sudo docker run -i -t ubuntu:16.04 /bin/bash
root@d10ad2bd62f7:/# 
======================>
Now, we are with this container in interactive mode.
Let us apply some linux commands as below:
========================>
root@d10ad2bd62f7:/# pwd
/
root@d10ad2bd62f7:/# ls
bin   dev  home  lib64  mnt  proc  run   srv  tmp  var
boot  etc  lib   media  opt  root  sbin  sys  usr
root@d10ad2bd62f7:/# cd home
root@d10ad2bd62f7:/home# ls
root@d10ad2bd62f7:/home# cd ../var
root@d10ad2bd62f7:/var# ls
backups  cache  lib  local  lock  log  mail  opt  run  spool  tmp
root@d10ad2bd62f7:/var# cd tmp
root@d10ad2bd62f7:/var/tmp# pwd
/var/tmp
root@d10ad2bd62f7:/var/tmp# ls
root@d10ad2bd62f7:/var/tmp# cd ../lib
root@d10ad2bd62f7:/var/lib# ls
apt  dpkg  initscripts  insserv  misc  pam  systemd  update-rc.d  urandom
root@d10ad2bd62f7:/var/lib# 
================================>

Now I want to create a file as below in this container:
==================>

root@d10ad2bd62f7:/var/lib# pwd
/var/lib
root@d10ad2bd62f7:/var/lib# cd ../../home
root@d10ad2bd62f7:/home# ls
root@d10ad2bd62f7:/home# touch file1.txt
===================>

Let me add some text into this file as below:
==========>
root@d10ad2bd62f7:/home# echo " Testing containers " > file1.txt
root@d10ad2bd62f7:/home# echo " Applying stop command on containers " > file1.txt
root@d10ad2bd62f7:/home# cat file1.txt
 Applying stop command on containers 
root@d10ad2bd62f7:/home# echo " Testing containers " > file1.txtroot@d10ad2bd62f7:/home# echo " Applying stop command on containers " >> file1.txt
root@d10ad2bd62f7:/home# ls
file1.txt
root@d10ad2bd62f7:/home# ls -l
total 4
-rw-r--r-- 1 root root 59 Nov 25 23:20 file1.txt
root@d10ad2bd62f7:/home# cat file1.txt 
Testing containers 
Applying stop command on containers 
root@d10ad2bd62f7:/home# 
===============>

I have applied some more linux file operations on this container as below:
=================>
root@d10ad2bd62f7:/home#      
root@d10ad2bd62f7:/home# cat file1.txt >> file2.txt
root@d10ad2bd62f7:/home# ls
file1.txt  file2.txt
root@d10ad2bd62f7:/home# ls -l
total 8
-rw-r--r-- 1 root root 59 Nov 25 23:20 file1.txt
-rw-r--r-- 1 root root 59 Nov 25 23:22 file2.txt
root@d10ad2bd62f7:/home# diff file1.txt file2.txt
root@d10ad2bd62f7:/home# echo " Applying restart command also on containers " >> file1.txt
root@d10ad2bd62f7:/home# ls -l
total 8
-rw-r--r-- 1 root root 105 Nov 25 23:23 file1.txt
-rw-r--r-- 1 root root  59 Nov 25 23:22 file2.txt
root@d10ad2bd62f7:/home# diff file1.txt file2.txt3d2
<  Applying restart command also on containers 
root@d10ad2bd62f7:/home# 
====================>
Now, let me apply a stop command on this container and see as 
below by using exit to come out and stop:
=====================>
root@155f4b0764b1:/# 
root@155f4b0764b1:/# exit
exit
vskumar@ubuntu:~$ sudo docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              f2a91732366c        4 days ago          1.85kB
ubuntu              16.04               20c44cd7596f        8 days ago          123MB
ubuntu              latest              20c44cd7596f        8 days ago          123MB
busybox             latest              6ad733544a63        3 weeks ago         1.13MB
busybox             1.24                47bcc53f74dc        20 months ago       1.11MB
vskumar@ubuntu:~$ sudo docker stop  d10ad2bd62f7
d10ad2bd62f7
vskumar@ubuntu:~$ 
=============>
Now, I want to check the containers status using ps -a command as below:
==============>
vskumar@ubuntu:~$ sudo docker ps -a
CONTAINER ID        IMAGE               COMMAND                 CREATED             STATUS                     PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"             2 minutes ago       Exited (0) 2 minutes ago                       zen_volhard
cb1ff260d48e        ubuntu              "ls /usr/src"           10 hours ago        Exited (0) 10 hours ago                        wonderful_hawking
b20691fd8fb5        ubuntu              "ls /usr"               10 hours ago        Exited (0) 10 hours ago                        friendly_mirzakhani
431ba4c53028        ubuntu              "ls"                    10 hours ago        Exited (0) 10 hours ago                        affectionate_nobel
2c31684bb1f4        ubuntu              "ls -la"                10 hours ago        Exited (0) 10 hours ago                        zealous_meitner
fe2e3b449daf        ubuntu              "ls -la /home/."        10 hours ago        Exited (0) 10 hours ago                        dreamy_shirley
c44bdd05b94d        ubuntu              "ls -la home."          10 hours ago        Exited (2) 10 hours ago                        elastic_pasteur
8b8afa82859a        ubuntu              "ls -la"                10 hours ago        Exited (0) 10 hours ago                        festive_panini
2811eb37af61        ubuntu              "ls -la 604831dbce2a"   10 hours ago        Exited (2) 10 hours ago                        jolly_swartz
604831dbce2a        ubuntu:16.04        "/bin/bash"             10 hours ago        Exited (0) 10 hours ago                        vibrant_ride
718636415a7f        ubuntu:16.04        "/bin/bash"             11 hours ago        Exited (0) 10 hours ago                        reverent_noyce
53a7751d4673        ubuntu:16.04        "/bin/bash"             12 hours ago        Exited (0) 12 hours ago                        musing_chandrasekhar
32bc16b508d4        ubuntu              "bash"                  13 hours ago        Exited (0) 13 hours ago                        eager_goldberg
1dd55efde43f        hello-world         "/hello"                13 hours ago        Exited (0) 13 hours ago                        peaceful_pasteur
a744246ffb8e        hello-world         "/hello"                15 hours ago        Exited (0) 15 hours ago                        naughty_wing
1ba71598b7b8        hello-world         "/hello"                15 hours ago        Exited (0) 15 hours ago                        musing_kare
vskumar@ubuntu:~$ 
===================>
you can see the latest status of our container;
155f4b0764b1        ubuntu:16.04        "/bin/bash"             2 minutes ago       Exited (0) 2 minutes ago                       zen_volhard
It means Docker  maintains in the logs on the usage of containers also.
Now, I want to start the previously stopped container using the docker start subcommand 
by specifying the container ID as an argument, as follows:
$ sudo docker start 155f4b0764b1
===============>
vskumar@ubuntu:~$ sudo docker start 155f4b0764b1
155f4b0764b1
vskumar@ubuntu:~$ 
===============>
Let us check the images status also as below:
==================> Copied the 1st two lines only ----->
vskumar@ubuntu:~$ sudo docker ps -a |more
CONTAINER ID        IMAGE               COMMAND                 CREATED         
    STATUS                      PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"             10 minutes ago  
    Up About a minute                               zen_volhard
11e293722c64        ubuntu:16.04        "/bin/bash"             12 minutes ago  
    Exited (0) 12 minutes ago  
====================>
It means it shows the current status of the container id:155f4b0764b1 
We need to notice one thing here.

By default, the docker start subcommand will not attach to the container.

We can attach it to the container either using the -a option in the docker start subcommand or by explicitly using the docker attach subcommand.

Now let us try these options.

We will see attach command

$ sudo docker attach 155f4b0764b1
=================>
vskumar@ubuntu:~$ 
vskumar@ubuntu:~$ sudo docker attach 155f4b0764b1
root@155f4b0764b1:/# 
root@155f4b0764b1:/#
=================>
So the attach command brought the container into interactive mode.
Now let me exit it and try the -a option with docker start command:
==================>
root@155f4b0764b1:/home# 
root@155f4b0764b1:/home# exit
exit
===============>
with start -a option:
=============>
vskumar@ubuntu:~$ sudo docker start -a 155f4b0764b1
root@155f4b0764b1:/# 
=================>
After exit, I have tried ps command:
=====================>
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         21 minutes ago      Up 3 minutes                            zen_volhard
vskumar@ubuntu:~$ 
======================>
From the above display you can see that its start and current status.
It means the container is active and running.
Now, I want to make another [below] container active.
1dd55efde43f        hello-world         "/hello"                13 hours ago Exited (0) 13 hours ago                        peaceful_pasteur
Let us see the ps command after these 2 containers are in active state.
I want to use the below command:
$ sudo docker start -a 1dd55efde43f
===================>
vskumar@ubuntu:~$ sudo docker start -a 1dd55efde43f

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

Let us  try something more ambitious, we can run an Ubuntu container with:
 $ docker run -it ubuntu bash

If you want to;
Share images, automate workflows, and more with a free Docker ID:
visit: https://cloud.docker.com/
For more examples and ideas, visit:
https://docs.docker.com/engine/userguide/

vskumar@ubuntu:~$ 
===================>
Please note the above container doesn't have a any os related process to 
keep running continuously. 
Just it displays the message only. Hence 
in the list it will not appear. 
Now, let me list the current processes using docker ps command:
===========>
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         32 minutes ago      Up 14 minutes                           zen_volhard
vskumar@ubuntu:~$ 
==============>
So as on now one container is running.

The next set of container controlling subcommands are docker pause and docker unpause.

The docker pause subcommand will freeze the execution of all the processes within the container.

The docker unpause subcommand will unfreeze the execution of all the processes within the container and resume the execution from the point where it was frozen.

Let us try the below command 
$sudo docker pause 155f4b0764b1
========================>
vskumar@ubuntu:~$ 
vskumar@ubuntu:~$ sudo docker pause 155f4b0764b1
155f4b0764b1
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                   PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         About an hour ago   Up 30 minutes (Paused)                       zen_volhard
vskumar@ubuntu:~$ 
==========================>
You can see the current status as Paused.
Now let me try unpause command also.
$ sudo docker unpause 155f4b0764b1
You can see the total output of this container with pause and unpause statuses:
===================>
vskumar@ubuntu:~$ 
vskumar@ubuntu:~$ sudo docker pause 155f4b0764b1
155f4b0764b1
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                   PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         About an hour ago   Up 30 minutes (Paused)                       zen_volhard
vskumar@ubuntu:~$ ^C
vskumar@ubuntu:~$ sudo docker unpause 155f4b0764b1
155f4b0764b1
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
155f4b0764b1        ubuntu:16.04        "/bin/bash"         About an hour ago   Up 32 minutes                           zen_volhard
vskumar@ubuntu:~$ 
======================>
Now, in this lab session finally we will use the stop command:

The container and the script running within it can be stopped using the docker stop subcommand, as shown below:

$ sudo docker stop 155f4b0764b1
=====================> 
vskumar@ubuntu:~$ sudo docker stop 155f4b0764b1
155f4b0764b1
vskumar@ubuntu:~$ sudo docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED STATUS              PORTS               NAMES
=============== It shows there is no active container =============>
Now, let me try with -a and more options.
=========== Partial display is shown here upto the container ===========>
vskumar@ubuntu:~$ sudo docker ps -a |more
CONTAINER ID        IMAGE               COMMAND                 CREATED         
    STATUS                         PORTS               NAMES
f123dbd09116        ubuntu:16.04        "/bin/bash"             6 minutes ago   
    Exited (0) 5 minutes ago                           elastic_nightingale
3cfdea29ce6e        ubuntu              "bash"                  14 minutes ago  
    Exited (0) 14 minutes ago                          gallant_nobel
155f4b0764b1        ubuntu:16.04        "/bin/bash"             About an hour ag
o   Exited (0) 17 seconds ago  
================================>

So far in this lab session, we have seen the differences of different commands to operate and control the containers. I would like to break this session for now. In the next blog we will see on how to manage “Housekeeping containers“.

 Vcard-Shanthi Kumar V

 

7. DevOps: How to track changes in a container

Docker-logo

In  continuation of my previous blog on “6. DevOps: How to work with interactive docker containers”, in this blog I would like to show some lab practice “How to track changes in a container”.

Tracking changes inside containers:

Now, let us see the container operations and tracking them.

Let’s launch a container in interactive mode, as we have done in previous session, we can use the below command.

$ sudo docker run -i -t ubuntu:16.04 /bin/bash 
=================>
vskumar@ubuntu:/var/log$ sudo docker run -i -t ubuntu:16.04 /bin/bash  
root@718636415a7f:/# ps
   PID TTY          TIME CMD
     1 pts/0    00:00:00 bash
     9 pts/0    00:00:00 ps
root@718636415a7f:/# ps -ef
UID         PID   PPID  C STIME TTY          TIME CMD
root          1      0  0 12:39 pts/0    00:00:00 /bin/bash
root         10      1  0 12:53 pts/0    00:00:00 ps -ef
root@718636415a7f:/# ls
bin  boot  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
root@718636415a7f:/# 
======================>
Now, let us go to home directory:
========>
root@718636415a7f:/# pwd
/
root@718636415a7f:/# cd home
root@718636415a7f:/home# pwd
/home
root@718636415a7f:/home# ls
root@718636415a7f:/home# 
==============>
Now, as a standalone machine of this docker container, 
I want to create 4 text files using touch command as below:
==============>
root@718636415a7f:/home# ls
root@718636415a7f:/home# ls -l
total 0
root@718636415a7f:/home# touch {vsk1,vsk2,vsk3,vsk4}
root@718636415a7f:/home# ls -l
total 0
-rw-r--r-- 1 root root 0 Nov 25 12:57 vsk1
-rw-r--r-- 1 root root 0 Nov 25 12:57 vsk2
-rw-r--r-- 1 root root 0 Nov 25 12:57 vsk3
-rw-r--r-- 1 root root 0 Nov 25 12:57 vsk4
root@718636415a7f:/home# 
======================>

I am adding some text to each of them as below:

====================>

root@718636415a7f:/home# pwd

/home

root@718636415a7f:/home# echo ‘Testing vsk1’ > vsk1

root@718636415a7f:/home# ls -l

total 4

-rw-r–r– 1 root root 13 Nov 25 13:02 vsk1

-rw-r–r– 1 root root 0 Nov 25 12:57 vsk2

-rw-r–r– 1 root root 0 Nov 25 12:57 vsk3

-rw-r–r– 1 root root 0 Nov 25 12:57 vsk4

root@718636415a7f:/home# echo ‘Testing vsk2’ > vsk2

root@718636415a7f:/home# echo ‘Testing vsk3’ > vsk3

root@718636415a7f:/home# echo ‘NOT Testing vsk4’ > vsk4

root@718636415a7f:/home# ls -l

total 16

-rw-r–r– 1 root root 13 Nov 25 13:02 vsk1

-rw-r–r– 1 root root 13 Nov 25 13:02 vsk2

-rw-r–r– 1 root root 13 Nov 25 13:02 vsk3

-rw-r–r– 1 root root 17 Nov 25 13:02 vsk4

root@718636415a7f:/home#

=====================>

I have created 4 files and added some text into them.

Now, I want to execute a diff command on them:

==========================>

root@718636415a7f:/home# diff vsk1 vsk2

1c1

< Testing vsk1

> Testing vsk2

root@718636415a7f:/home# diff vsk2 vsk3

1c1

< Testing vsk2

> Testing vsk3

root@718636415a7f:/home# echo ‘NOT Testing vsk4’ > vsk1

root@718636415a7f:/home# diff vsk1 vsk4

root@718636415a7f:/home# diff vsk2 vsk4

1c1

< Testing vsk2

> NOT Testing vsk4

root@718636415a7f:/home#

===========================>

Now, I want to exit this container and go back to docker host.

I have detached it using exit.

And back to docker host.

Now, I want to use the diff command as below from host machine to the container:

===========================>

root@718636415a7f:/home# ls -l

total 16

-rw-r–r– 1 root root 17 Nov 25 13:05 vsk1

-rw-r–r– 1 root root 13 Nov 25 13:02 vsk2

-rw-r–r– 1 root root 13 Nov 25 13:02 vsk3

-rw-r–r– 1 root root 17 Nov 25 13:02 vsk4

root@718636415a7f:/home# exit

exit

vskumar@ubuntu:/var/log$ sudo docker diff 718636415a7f

[sudo] password for vskumar:

C /home

A /home/vsk1

A /home/vsk2

A /home/vsk3

A /home/vsk4

C /root

A /root/.bash_history

vskumar@ubuntu:/var/log$

=====================>

The 1st line ‘C /home’ shows; the home directory is modified by showing ‘C’ as changed.

The ‘A’ shows;  before each line denotes the file is added.

If you have a deleted file, it can show as ‘D’ before the file.

Also please let us note here on how docker engine picks up the image with the below priority;

When we work with an image and if we don’t specify that image name, then the latest image (recently generated) will be identified and used by the Docker Engine.

We can check the status of the containers as below using ps -a:

You can see a detailed output from this command from the below display:

==================================>

vskumar@ubuntu:/var/log$ ls

alternatives.log bootstrap.log dmesg fsck kern.log speech-dispatcher unattended-upgrades wtmp

apport.log btmp dpkg.log gpu-manager.log lastlog syslog upstart Xorg.0.log

apt cups faillog hp lightdm syslog.1 vmware Xorg.0.log.old

auth.log dist-upgrade fontconfig.log installer samba syslog.2.gz vmware-vmsvc.log

vskumar@ubuntu:/var/log$ sudo docker ps -a

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

cb1ff260d48e ubuntu “ls /usr/src” 3 minutes ago Exited (0) 3 minutes ago wonderful_hawking

b20691fd8fb5 ubuntu “ls /usr” 3 minutes ago Exited (0) 3 minutes ago friendly_mirzakhani

431ba4c53028 ubuntu “ls” 3 minutes ago Exited (0) 3 minutes ago affectionate_nobel

2c31684bb1f4 ubuntu “ls -la” 3 minutes ago Exited (0) 3 minutes ago zealous_meitner

fe2e3b449daf ubuntu “ls -la /home/.” 4 minutes ago Exited (0) 4 minutes ago dreamy_shirley

c44bdd05b94d ubuntu “ls -la home.” 4 minutes ago Exited (2) 4 minutes ago elastic_pasteur

8b8afa82859a ubuntu “ls -la” 4 minutes ago Exited (0) 4 minutes ago festive_panini

2811eb37af61 ubuntu “ls -la 604831dbce2a” 4 minutes ago Exited (2) 4 minutes ago jolly_swartz

604831dbce2a ubuntu:16.04 “/bin/bash” 8 minutes ago Exited (0) 6 minutes ago vibrant_ride

718636415a7f ubuntu:16.04 “/bin/bash” 45 minutes ago Exited (0) 18 minutes ago reverent_noyce

53a7751d4673 ubuntu:16.04 “/bin/bash” 2 hours ago Exited (0) 2 hours ago musing_chandrasekhar

32bc16b508d4 ubuntu “bash” 3 hours ago Exited (0) 3 hours ago eager_goldberg

1dd55efde43f hello-world “/hello” 3 hours ago Exited (0) 3 hours ago peaceful_pasteur

a744246ffb8e hello-world “/hello” 5 hours ago Exited (0) 5 hours ago naughty_wing

1ba71598b7b8 hello-world “/hello” 5 hours ago Exited (0) 5 hours ago musing_kare

vskumar@ubuntu:/var/log$

============================>

I would like to terminate the session at this point. In the next blog I would like to present “How to control and operate docker containers”.

Vcard-Shanthi Kumar V-v3

5. DevOps: How to work with Docker Images

Docker-logo

In  continuation of my previous blog on “4. DevOps: How to work with Docker Containers”, in this blog I would like to give some lab practice on Docker Images.

How to pull the docker public images ?:
Docker portal will have numerous images available  under public.
Now, there is a need for us to know the usage of docker pull command, which is the defacto command to download Docker images.

Now, in this section, we will use the busybox image, one of the smallest but a very handy Docker image, to dive deep into Docker image handling:
$sudo docker pull busybox
============= Output ============>
vskumar@ubuntu:/var/tmp$ sudo docker pull busybox
Using default tag: latest
latest: Pulling from library/busybox
0ffadd58f2a6: Pull complete
Digest: sha256:bbc3a03235220b170ba48a157dd097dd1379299370e1ed99ce976df0355d24f0
Status: Downloaded newer image for busybox:latest
vskumar@ubuntu:/var/tmp$
=================>
Sometimes it might reject this request. We need to keep on trying to get it. I tried 4 times at different timings to connect to it.
Please note now, we have three images as below through all of our so far exercises:
===================>
vskumar@ubuntu:/var/log$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest f2a91732366c 4 days ago 1.85kB
ubuntu latest 20c44cd7596f 7 days ago 123MB
busybox latest 6ad733544a63 3 weeks ago 1.13MB
vskumar@ubuntu:/var/log$
===============>
Now, let us stop the docker services and check the status as below:
=================>
vskumar@ubuntu:/var/log$ sudo docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest f2a91732366c 4 days ago 1.85kB
ubuntu latest 20c44cd7596f 7 days ago 123MB
busybox latest 6ad733544a63 3 weeks ago 1.13MB
vskumar@ubuntu:/var/log$ sudo service docker stop
vskumar@ubuntu:/var/log$ sudo service docker status
● docker.service – Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: e
Active: inactive (dead) since Sat 2017-11-25 02:52:25 PST; 8s ago
Docs: https://docs.docker.com
Process: 1224 ExecStart=/usr/bin/dockerd -H fd:// (code=exited, status=0/SUCCE
Main PID: 1224 (code=exited, status=0/SUCCESS)
Nov 25 02:21:42 ubuntu dockerd[1224]: time=”2017-11-25T02:21:42.863518710-08:00″
Nov 25 02:21:43 ubuntu dockerd[1224]: time=”2017-11-25T02:21:43-08:00″ level=inf
Nov 25 02:27:08 ubuntu dockerd[1224]: time=”2017-11-25T02:27:08.010096274-08:00″
Nov 25 02:27:08 ubuntu dockerd[1224]: time=”2017-11-25T02:27:08-08:00″ level=inf
Nov 25 02:27:08 ubuntu dockerd[1224]: time=”2017-11-25T02:27:08.199685599-08:00″
Nov 25 02:52:25 ubuntu dockerd[1224]: time=”2017-11-25T02:52:25.010875880-08:00″
Nov 25 02:52:25 ubuntu systemd[1]: Stopping Docker Application Container Engine.
Nov 25 02:52:25 ubuntu dockerd[1224]: time=”2017-11-25T02:52:25.081714537-08:00″
Nov 25 02:52:25 ubuntu systemd[1]: Stopped Docker Application Container Engine.
Nov 25 02:52:25 ubuntu systemd[1]: Stopped Docker Application Container Engine.
vskumar@ubuntu:/var/log$
====================>
You can see the inactive status of docker.
In such cases, restart the Docker service, as shown here:

$ sudo service docker restart
You can see the output as below:
==================>
vskumar@ubuntu:/var/log$ sudo service docker restart
vskumar@ubuntu:/var/log$ sudo service docker status 
docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: e
   Active: active (running) since Sat 2017-11-25 02:54:42 PST; 6s ago
     Docs: https://docs.docker.com
 Main PID: 3769 (dockerd)
    Tasks: 18
   Memory: 24.6M
      CPU: 989ms
   CGroup: /system.slice/docker.service
           ├─3769 /usr/bin/dockerd -H fd://
           └─3778 docker-containerd --config /var/run/docker/containerd/containe

Nov 25 02:54:41 ubuntu dockerd[3769]: time="2017-11-25T02:54:41.159062708-08:00"
Nov 25 02:54:41 ubuntu dockerd[3769]: time="2017-11-25T02:54:41.159806997-08:00"
Nov 25 02:54:41 ubuntu dockerd[3769]: time="2017-11-25T02:54:41.163503112-08:00"
Nov 25 02:54:41 ubuntu dockerd[3769]: time="2017-11-25T02:54:41.743276580-08:00"
Nov 25 02:54:41 ubuntu dockerd[3769]: time="2017-11-25T02:54:41.955217284-08:00"
Nov 25 02:54:41 ubuntu dockerd[3769]: time="2017-11-25T02:54:41.975961283-08:00"
Nov 25 02:54:42 ubuntu dockerd[3769]: time="2017-11-25T02:54:42.092220161-08:00"
Nov 25 02:54:42 ubuntu dockerd[3769]: time="2017-11-25T02:54:42.094334663-08:00"
Nov 25 02:54:42 ubuntu systemd[1]: Started Docker Application Container Engine.
Nov 25 02:54:42 ubuntu dockerd[3769]: time="2017-11-25T02:54:42.190194886-08:00"

vskumar@ubuntu:/var/log$ 

========================>

Now, let us reconfirm the existing docker images as below:
================>

vskumar@ubuntu:/var/log$ ^C
vskumar@ubuntu:/var/log$ sudo docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              f2a91732366c        4 days ago          1.85kB
ubuntu              latest              20c44cd7596f        7 days ago          123MB
busybox             latest              6ad733544a63        3 weeks ago         1.13MB
vskumar@ubuntu:/var/log$ 
=======================>

By default, Docker always uses the image that is tagged as latest.

Each image variant can be directly identified by qualifying it with an appropriate tag.

An image can be tag-qualified by adding a colon (:) between the tag and the repository name (<repository>:<tag>). For demonstration, we will pull the 1.24 tagged version of busybox as shown here:

Now, For lab demonstration, we will pull the 1.24 tagged version of busybox as shown here:

$ sudo docker pull busybox:1.24

Now. You can see the total output before and after executing the above command:

==============================>

vskumar@ubuntu:/var/log$ ^C

vskumar@ubuntu:/var/log$ sudo docker images

REPOSITORY TAG IMAGE ID CREATED SIZE

hello-world latest f2a91732366c 4 days ago 1.85kB

ubuntu latest 20c44cd7596f 7 days ago 123MB

busybox latest 6ad733544a63 3 weeks ago 1.13MB

vskumar@ubuntu:/var/log$ ^C

vskumar@ubuntu:/var/log$

vskumar@ubuntu:/var/log$

vskumar@ubuntu:/var/log$ sudo docker pull busybox:1.24

1.24: Pulling from library/busybox

385e281300cc: Pull complete

a3ed95caeb02: Pull complete

Digest: sha256:8ea3273d79b47a8b6d018be398c17590a4b5ec604515f416c5b797db9dde3ad8

Status: Downloaded newer image for busybox:1.24

vskumar@ubuntu:/var/log$ sudo docker images

REPOSITORY TAG IMAGE ID CREATED SIZE

hello-world latest f2a91732366c 4 days ago 1.85kB

ubuntu latest 20c44cd7596f 7 days ago 123MB

busybox latest 6ad733544a63 3 weeks ago 1.13MB

busybox 1.24 47bcc53f74dc 20 months ago 1.11MB

vskumar@ubuntu:/var/log$

==============================>

There are two busybox containers with different versions.

So, on the basis of TAG values the containers are being pulled.

How to Search Docker images:

So far we have pulled the known images from the docker-hub.

Let us identify some docker images by using a search option as below. We can search for Docker images in the Docker Hub Registry using the docker search subcommand, as shown in this example:

$ sudo docker search mysql

You can see the displayed output of mysql images from the Docker Hub Registry:

=============>

vskumar@ubuntu:/var/log$ sudo docker search mysql

NAME DESCRIPTION STARS OFFICIAL AUTOMATED

mysql MySQL is a widely used, open-source relation… 5278 [OK]

mariadb MariaDB is a community-developed fork of MyS… 1634 [OK]

mysql/mysql-server Optimized MySQL Server Docker images. Create… 368 [OK]

percona Percona Server is a fork of the MySQL relati… 303 [OK]

hypriot/rpi-mysql RPi-compatible Docker Image with Mysql 74

zabbix/zabbix-server-mysql Zabbix Server with MySQL database support 64 [OK]

centurylink/mysql Image containing mysql. Optimized to be link… 53 [OK]

sameersbn/mysql 48 [OK]

zabbix/zabbix-web-nginx-mysql Zabbix frontend based on Nginx web-server wi… 38 [OK]

tutum/mysql Base docker image to run a MySQL database se… 29

1and1internet/ubuntu-16-nginx-php-phpmyadmin-mysql-5 ubuntu-16-nginx-php-phpmyadmin-mysql-5 17 [OK]

schickling/mysql-backup-s3 Backup MySQL to S3 (supports periodic backup… 16 [OK]

centos/mysql-57-centos7 MySQL 5.7 SQL database server 15

linuxserver/mysql A Mysql container, brought to you by LinuxSe… 12

centos/mysql-56-centos7 MySQL 5.6 SQL database server 6

openshift/mysql-55-centos7 DEPRECATED: A Centos7 based MySQL v5.5 image… 6

frodenas/mysql A Docker Image for MySQL 3 [OK]

dsteinkopf/backup-all-mysql backup all DBs in a mysql server 3 [OK]

circleci/mysql MySQL is a widely used, open-source relation… 2

cloudfoundry/cf-mysql-ci Image used in CI of cf-mysql-release 0

cloudposse/mysql Improved `mysql` service with support for `m… 0 [OK]

ansibleplaybookbundle/rhscl-mysql-apb An APB which deploys RHSCL MySQL 0 [OK]

astronomerio/mysql-sink MySQL sink 0 [OK]

inferlink/landmark-mysql landmark-mysql 0 [OK]

astronomerio/mysql-source MySQL source 0 [OK]

vskumar@ubuntu:/var/log$ ^C

vskumar@ubuntu:/var/log$

====================>

You can get the top 5 images by suing head -5 linux command.

$sudo docker search mysql | head -5

=============>

vskumar@ubuntu:/var/log$ sudo docker search mysql | head -5

NAME DESCRIPTION STARS OFFICIAL AUTOMATED

mysql MySQL is a widely used, open-source relation… 5278 [OK]

mariadb MariaDB is a community-developed fork of MyS… 1634 [OK]

mysql/mysql-server Optimized MySQL Server Docker images. Create… 368 [OK]

percona Percona Server is a fork of the MySQL relati… 303 [OK]

vskumar@ubuntu:/var/log$

===============>

If you see the above list, The mysql image curated and hosted by Docker Inc has a 5278 star rating, which is indicated as this is the most popular mysql image and aslo as Official image to use it. For security reasons we should use the official and highly rated images only.

As we planned, in this blog we have worked with the Docker images.

At this point we can stop this session and in the next blog we can see on “How to work with interactive containers”.

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SDLC & Agile – Interview questions for Freshers -4

Agile Cirlce1

In continuation of my previous blog [https://wordpress.com/post/vskumar.blog/1944]

on this subject following questions and answers are continued:

 

1.  What is a collaborative development approach in  agile development model ?

Ans: In any agile project as per the Agile manifesto principles the team need to pull up the ideas through a prototype like;  either phased prototype or iterative prototype or rapid prototype. With these pulled ideas, the team need to work together by sharing knowledge among themselves and which is considered as a collaborative development approach. 

2.  What is model storming during construction phase of an agile development model?

Ans: When the initial requirements are envisioned they all are being transmitted into different iterations. A single team or multiple teams need to execute the iteration during software code construction. The requirements also can be changed or newly added by the stakeholders as per the agile principles at any stage of Agile project phases.  The team need to be brain stormed to execute the iterations correctly and completely as per the user’s desire. The iteration can be considered as a single agile model for construction phase and this model storming can happen within team for clear understanding of SPRINT by each developer. During the model storming; the requirements decomposition happens like; from user story to design specifications those can lead to SPRINT items, and from design to code specifications. Depends on the team planning; sometimes the outcome of model storming can also be a TDD [Test Driven Design]. [Please look into my youtube videos on Agile topic reusable code example]

 

3. What is Test Driven Design [TDD]?

Ans: Any requirement [story] need to be decomposed into design requirement. Each design requirement need to be converted into code through construction phase. When the code is visualized [before development] by the developer a test driven scenario need to be identified or visualized by the developer and it need to be documented into a test case with different test design steps. Once the developer feels this test case can be executed by using different code paths the developer can start the code writing, this concept is called Test Driven Design and using this TDD specification the development can be started.  Hence the Agile developers need to make TDD  1st ready and plan for code writing, review and unit testing. Sometimes the TDD  can be the outcome of the model storming also.

4. What is confirmatory testing?

Ans: In any software build there can be defects through different levels of testing. When the developer fixes one or more defects and deploy code in test environment, the test engineer need to retest it for confirming the software function with reference to the regression requirements or functionality and the fixes [if any]. For every fix confirmation test is mandatory.

 5.  What is evolving documentation?

Ans: As per the agile process when the code is constructed and tested the prepared documents need to be updated with reference to the tested and certified build. If any new requirement has to be incorporated into document, the documentation evolving is an ongoing activity for an iteration build till it goes to production.

 

6.  What is internally deploying software?

Ans: Once the construction is over for an iteration requirement, software can be unit tested and integration tested. If it is passed, it can be move to other test environments. As per the deployment process when we are moving software into the different environments [after test certification or confirmation] the build is known as internally deployable software.

 

7.  When can you finalize the documentation in agile model?

Ans: During the transition stage once the acceptance test is signed off users suggestions are considered to finalize the documentation.

 

8.  What are  tangible and intangible benefits for users?

Ans: In any business requirements there are direct benefits from business to incorporate software requirements into software system which is considered as tangible [direct] benefits. There are intangible [indirect benefits] also  by incorporating different requirements into software with a business usage.

Example: If  the system performance is increased by a technical design  in the software architecture, users can access the data faster which is intangible benefits. Then the  iteration can facilitate to perform the software with faster data access or the web pages appearance can be faster. Sometimes this kind of requirements can come into  technical areas rather than coming through a user story in Agile and those can be intangible benefit. Even we might consider an upgrade to database or OS or memory, etc.  then also the data access speed can be increased.

 

9.  What is the feedback analysis? When it can be done?

Ans: As per the agile principles the stakeholder collaboration is an ongoing activity. At any time the stakeholder can give informal or formal feedback for any software items or in any approach followed by agile teams. In agile model many times informal feedback can happen during the discussion. At the same time the scheduled reviews also can happen. During the review the feedback can be given by the reviewers. Even a test result can come into a feedback category. All these feedback items need to be analyzed for delivering a working software by the teams as per the principles.  Sometimes the feedback analysis outcome can come into process improvements areas for the next iteration and these should be considered for Retrospective items. Hence the feedback analysis is a mandated activity at every task completion stage in  Agile project.

 

10.  What is demo in agile model?

Ans: With reference to the rapid prototype approach agile teams are supposed to demonstrate skeleton design for a new module. it is a plan to demonstrate skeleton system to the stakeholder and to get the feedback for processing further SPRINT  or Iteration items. This demo is organized depends on the software or initial plan for a given iteration.

Keep watching this site for further updates.

Contact for any guidance/coaching.

 

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SDLC & Agile – Interview questions for Freshers -2

Agile Cirlce1

In continuation of my previous questions blog [https://vskumar.blog/2017/09/04/sdlc-agile-interview-questions-for-freshers-1] on this topic these were made.

SDLC and Agile Model:

Questions on SDLC Phases:

1. How the agile methodology has been architected?

Ans: The agile methodology has been architected with 12 principles to govern the agile development approach.

2. What is highest priority during agile development model?

Ans: The highest priority is customer satisfaction and the early and continuous delivery of software which will work for the customer requirement.

3. Why the agile development models need to accept the request on irrespective of the development stage?

Ans: As per the  fundamental approach of agile development  it provides facility to the users towards inception of new or enhanced requirements before the delivery.

4. During agile development approach who all need to work together?

Ans: The business people and software developers need to work collaboratively and consistently throughout the project life cycle.

5. To get the right delivery what do we need to do during agile development model?

Ans: In agile project we need to have self motivated individuals at the same time we also need to supply the required human and nonhuman resources to get the job done.

6. When the life cycle of agile model ends?

Ans: The agile model continues till the retirement of the product or project. When the customer decides the retirement of the product then the project operation is terminated. 

7. Why do we need to have face to face conversation during agile development approach?

Ans: The agile principle guides to have face to face conversation among the project resources to have most efficient and effective method of communication.

8. How can you measure the progress and success of agile project?

Ans: The basic concept of agile is to deliver the working software of component.

9. How  the agile development process need to be promoted and to whom  all ?

Ans: Agile development process need to be promoted in a  sustainable development for continuous delivery to the sponsors, developers and users.

10. Why do we need technical excellence and good design project delivery?

Ans: The concept of the agile is for continuous delivery to the users as per the requirements in an iterative development approach. The team capacity needs to be accelerated towards the functions and processes to work on good software design.

Keep watching this site for further updates.

Contact for any guidance/coaching.

View my UrbanPro-profile

URL is : https://www.urbanpro.com/vskumar 

 

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SDLC & Agile – Interview questions for Freshers -1

Agile Cirlce1

If you are a fresher for an IT  job trials this might be useful.

Please note as per the current global IT Industry trend most of the IT organizations have moved into Agile SDLC  and Continuous delivery cycles. Hence you, being fresher should be ready with this knowledge. I have made some of the below questions related to this topic.

[Also look into my old blog: https://vskumar.blog/2016/11/24/on-job-training-for-future-software-engineers-freshers-how-it-saves-their-career-time/]

SDLC AND Agile Model:

Questions on SDLC Phases:

1. What are the general phases for SDLC [Software Development Life Cycle] ?

Ans: In any development model  [SDLC] following are the different phases for software delivery : 

a) Requirements Investigation and analyzing

b) Design

c) Development

d) Implementation

e) Management

2. Where can you get requirement specifications in SDLC?

Ans: During the phase of Requirement investigation and analysis, the output will be Software Requirement Specifications. In every project during this phase user involvement is essential to get the business requirements to make the right software.

3. What is the procedure to derive the design specification?

Ans: During design phase the design specifications will be output of this activity. During this phase the final SRS is considered and it should be derived for design specification against each requirement. One requirement can have more than one design specifications. Basically you will be decomposed the software requirement into one or more design specification(s).

4. What is development or construction?

Ans: Once the design specifications have been baselined, the developer takes the design specifications to convert them into code. This activity is called constructing or developing code. The technology should be used for coding need to be  specified in the design documentation. Example: Let us assume you want to develop the code in Java, so the technology should be Java.

5. What is implementation in SDLC?

Ans: The implementation activity need to be started once the code construction is completed, the code construction involves coding, code review and unit testing, integration testing. Once these 3 tasks are completed the project is moved to next phase that is implementation. During implementation phase the relevant test environment is considered for deployment of software builds for test cycles. Depends on the SDLC model;  system testing and user acceptance testing can be performed, during the implementation software build can be deployed into live  once the user certify UAT [User Acceptance Testing]. The Live environment is also called production environment.

 

6. What is the meaning for  software management and retirement?

Ans: Once the software is deployed into production or live environment under first release there can be bug fixes  or software enhancements; those can occur under application management life cycle and which can be a software management also. With this concept software is being upgraded during its life time. When the new technology or business systems are considered towards   equivalent or more of the current software features then current software build should  be retired.

Example: A mainframe [COBOL/DB2/CICS] application can be converted into windows based with Java technology. Then the existing COBOL/DB2/CICS application can be planned for a retirement with the replacement of the newly planned application. The new application can also have some more software features or the same features can be implemented.

Questions on Agile:

7. How the agile development model pulls the ideas ?

Ans: Agile development model pulls the ideas in a phased manner in the following way, by using a) Prototyping   b) iterative development c) Rapid prototyping. During these phases the stakeholders or users involvement is mandatory. Their needs or suggestions also comes into the ideas for making the right software.

8. How the agile model champions the ideas?

Ans: By following various phases, different ideas are generated into the agile model. Using this approach it accelerates  the software engineering team to get the right results through different software delivery iterations.

9. Why traditional approach of SDLC is not suitable for agile development model?

Ans: During the traditional approach we do not have prototyping and iterative development in the SDLC. Using the prototyping the demo can be conducted on a conceptual model of the [new or existing] software. Then the  users can visualize these thoughts to extend the demo version into their live software. Then iterations comes into picture as  part by part to deliver  the working software in the agile development model.

To give you with some  more clarity;  Agile development model involves continuous construction and delivery using the phases of prototyping and iterative. For each iteration there can be prototype demonstration. Once the demo is approved the iteration will start for construction and implementation. In traditional model if we want to use for prototyping there is a phased prototype model and rapid prototype model are used, once they are approved by users the project team need to choose one of the traditional model SDLC. In this case there are two parts of delivery need to be considered where as in an agile model they are in-built for fast planning and iteration.

10. During agile model what kind of teams need to be formed to initiate the project?

Ans: To work in the agile development project we need the teams in small size, highly talented and responsive people.

11. During agile model how software requirements  are considered for delivery?

Ans: Agile team needs to consider the essential,  prioritized and deliverable requirements [within cycle time] from the users and construct the software in small increments those are called SPRINTS for delivery.

SW-Eng interviews

 

Next series of questions are continued……… in the below blog url:

https://vskumar.blog/2017/09/28/sdlc-agile-interview-questions-for-freshers-2/

You can look for my agile topic based videos:

https://www.youtube.com/edit?o=U&video_id=zCR6GP1ji60

 

https://www.youtube.com/edit?o=U&video_id=DiIhkCby0tU

 

 

If you are looking for any guidance please contact me and use the below Vcard:

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How to Reduce Agile cycle time with reusable code ? [with Video lessons] # Kindle

Agile practices and the importance of Re-usable code libraries for cycle time reductionReusable code usage for Agile iterations planning by examples:

In many Agile transformation sessions the Agile practitioners or savvy’s discuss more on the process related activities rather than elaborating on the technical or software engineering process steps to reduce the cycle time.

At the same time prior to the Agile meetings, activity efforts need to be defined by the designers and the developers. Unless they identify the size of the reusable code components in the applications it is not worth for conducting the Release or Sprint planning meetings for planning of the iterations.

Hence it is the moral responsibility of the technical teams to apply this kind of practices ahead of Agile process or Scrum meetings.

If you are interested to know what reusable code with examples is, this E-Book can be useful. Using this technique, you can plan for code refractor and its cleaning also to get ROI on future Agile iterations. During Scrum meetings, these are the important topics where technical people need to discuss for customer’s ROI acceleration planning and also the cycle time reduction acceleration. The team’s technical capabilities also can be accelerated by following these practices regularly.

I have considered an application example of E-commerce site building for defining the Sprint planning and their iterations. Each iteration has been divided into different reusable code components design parts.

The relevant graphics have been designed and added into this E-book. The software configuration processes with Code Items process have been discussed also.

One can answer the following after understanding this E-Book content:
How to define the reusable code?
How the Iterations can be planned?
Is it possible to demonstrate the iterations cycle time reduction?
What are the entry criteria for Sprint planning?
What are the jumpstart activities required for designers before Agile release meeting?
How to manage the code components with configuration management process?
How to plan the efforts reduction for Sprint cycles?

The proposed or mandatory readers are:
Agile developers
Agile Designers
Agile PMS
Agile Product Owners
Agile teams
Who all intended to learn Agile Practices?

It is cheaper now, please visit: http://www.amazon.com/Technical-best-practices-reusable-iterations-ebook/dp/B012CHK20Q/ref=sr_1_10?ie=UTF8&qid=1452047932&sr=8-10&keywords=Shanthi+Vemulapalli

Reusable-code-Cover1-Pixels

 

 

 

 

 

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Visit for Agile interview questions:

https://vskumar.blog/2017/09/04/sdlc-agile-interview-questions-for-freshers-1/

Visit for DevOps FAQs:

Devops-practices-faqs-1

 

https://vskumar.blog/2017/10/14/typical-devops-roles-and-activities/