Category Archives: CDI

23.DevOps: How to install Ansible on Ubuntu [Linux] VM ?

 

ansible-logo.png

In this blog, I would like to demonstrate  “Installing Ansible on Ubuntu VM”.

At the End of this blog you can see the demonstrated Video.

Let us follow the below steps:

Step 1:
To get Ansible for Ubuntu is to add the project’s PPA (personal package archive) to ubuntu system.
We can add the Ansible PPA by typing the following command:

$sudo apt-add-repository ppa:ansible/ansible

=== Screen output ====>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ sudo apt-add-repository ppa:ansible/ansible
[sudo] password for vskumar:
Ansible is a radically simple IT automation platform that makes your applications and systems easier to deploy.
Avoid writing scripts or custom code to deploy and update your applications— automate in a language that
approaches plain English, using SSH, with no agents to install on remote systems.

http://ansible.com/
More info: https://launchpad.net/~ansible/+archive/ubuntu/ansible
Press [ENTER] to continue or ctrl-c to cancel adding it

gpg: keyring `/tmp/tmpzhb6yoiy/secring.gpg’ created
gpg: keyring `/tmp/tmpzhb6yoiy/pubring.gpg’ created
gpg: requesting key 7BB9C367 from hkp server keyserver.ubuntu.com
gpg: /tmp/tmpzhb6yoiy/trustdb.gpg: trustdb created
gpg: key 7BB9C367: public key “Launchpad PPA for Ansible, Inc.” imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
OK
vskumar@ubuntu:~$
========= Added Ansible to PPA ===>
Step 2:
Now, let us refresh ubuntu [VM] system package index, so that it is aware of the packages available in the PPA.
Then, we can install the software.
We need to follow the below commands:
$sudo apt-get update
$sudo apt-get install ansible
==== Update package=======>
vskumar@ubuntu:~$ sudo apt-get update
Get:1 http://ppa.launchpad.net/ansible/ansible/ubuntu xenial InRelease [18.0 kB]
Hit:2 https://download.docker.com/linux/ubuntu xenial InRelease
Hit:3 http://archive.ubuntu.com/ubuntu xenial InRelease
Hit:4 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial InRelease
Get:5 http://ppa.launchpad.net/ansible/ansible/ubuntu xenial/main amd64 Packages [540 B]
Ign:6 https://pkg.jenkins.io/debian-stable binary/ InRelease
Get:7 http://ppa.launchpad.net/ansible/ansible/ubuntu xenial/main i386 Packages [540 B]
Hit:8 https://pkg.jenkins.io/debian-stable binary/ Release
Get:10 http://ppa.launchpad.net/ansible/ansible/ubuntu xenial/main Translation-en [344 B]
Fetched 19.5 kB in 2s (7,857 B/s)
Reading package lists… Done
vskumar@ubuntu:~$
===== Updated =====>

Step 3:
Now, let us install Ansible as below:
==== Installing Ansible =====>
vskumar@ubuntu:~$ sudo apt-get install ansible
Reading package lists… Done
Building dependency tree
Reading state information… Done
The following additional packages will be installed:
python-ecdsa python-httplib2 python-jinja2 python-markupsafe python-paramiko
sshpass
Suggested packages:
python-jinja2-doc
The following NEW packages will be installed:
ansible python-ecdsa python-httplib2 python-jinja2 python-markupsafe
python-paramiko sshpass
0 upgraded, 7 newly installed, 0 to remove and 0 not upgraded.
Need to get 3,001 kB of archives.
After this operation, 24.1 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-markupsafe amd64 0.23-2build2 [15.5 kB]
Get:2 http://ppa.launchpad.net/ansible/ansible/ubuntu xenial/main amd64 ansible all 2.4.3.0-1ppa~xenial [2,690 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-jinja2 all 2.8-1 [109 kB]
Get:4 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-ecdsa all 0.13-2 [34.0 kB]
Get:5 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-paramiko all 1.16.0-1 [109 kB]
Get:6 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-httplib2 all 0.9.1+dfsg-1 [34.2 kB]
Get:7 http://archive.ubuntu.com/ubuntu xenial/universe amd64 sshpass amd64 1.05-1 [10.5 kB]
Fetched 3,001 kB in 9s (306 kB/s)
Selecting previously unselected package python-markupsafe.
(Reading database … 218383 files and directories currently installed.)
Preparing to unpack …/python-markupsafe_0.23-2build2_amd64.deb …
Unpacking python-markupsafe (0.23-2build2) …
Selecting previously unselected package python-jinja2.
Preparing to unpack …/python-jinja2_2.8-1_all.deb …
Unpacking python-jinja2 (2.8-1) …
Selecting previously unselected package python-ecdsa.
Preparing to unpack …/python-ecdsa_0.13-2_all.deb …
Unpacking python-ecdsa (0.13-2) …
Selecting previously unselected package python-paramiko.
Preparing to unpack …/python-paramiko_1.16.0-1_all.deb …
Unpacking python-paramiko (1.16.0-1) …
Selecting previously unselected package python-httplib2.
Preparing to unpack …/python-httplib2_0.9.1+dfsg-1_all.deb …
Unpacking python-httplib2 (0.9.1+dfsg-1) …
Selecting previously unselected package sshpass.
Preparing to unpack …/sshpass_1.05-1_amd64.deb …
Unpacking sshpass (1.05-1) …
Selecting previously unselected package ansible.
Preparing to unpack …/ansible_2.4.3.0-1ppa~xenial_all.deb …
Unpacking ansible (2.4.3.0-1ppa~xenial) …
Processing triggers for man-db (2.7.5-1) …
Setting up python-markupsafe (0.23-2build2) …
Setting up python-jinja2 (2.8-1) …
Setting up python-ecdsa (0.13-2) …
Setting up python-paramiko (1.16.0-1) …
Setting up python-httplib2 (0.9.1+dfsg-1) …
Setting up sshpass (1.05-1) …
Setting up ansible (2.4.3.0-1ppa~xenial) …
vskumar@ubuntu:~$
=== Ansible installation is done! ====>

Step 4:
Let us add the below python properties  also:

sudo apt-get install python-software-properties
== Installing python properties =======>
vskumar@ubuntu:/etc/ansible$ sudo apt-get install python-software-properties
Reading package lists… Done
Building dependency tree
Reading state information… Done
The following additional packages will be installed:
python-apt python-pycurl
Suggested packages:
python-apt-dbg python-apt-doc libcurl4-gnutls-dev python-pycurl-dbg
python-pycurl-doc
The following NEW packages will be installed:
python-apt python-pycurl python-software-properties
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 202 kB of archives.
After this operation, 927 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-apt amd64 1.1.0~beta1build1 [139 kB]
Get:2 http://archive.ubuntu.com/ubuntu xenial/main amd64 python-pycurl amd64 7.43.0-1ubuntu1 [43.3 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial/universe amd64 python-software-properties all 0.96.20 [20.1 kB]
Fetched 202 kB in 1s (181 kB/s)
Selecting previously unselected package python-apt.
(Reading database … 220895 files and directories currently installed.)
Preparing to unpack …/python-apt_1.1.0~beta1build1_amd64.deb …
Unpacking python-apt (1.1.0~beta1build1) …
Selecting previously unselected package python-pycurl.
Preparing to unpack …/python-pycurl_7.43.0-1ubuntu1_amd64.deb …
Unpacking python-pycurl (7.43.0-1ubuntu1) …
Selecting previously unselected package python-software-properties.
Preparing to unpack …/python-software-properties_0.96.20_all.deb …
Unpacking python-software-properties (0.96.20) …
Setting up python-apt (1.1.0~beta1build1) …
Setting up python-pycurl (7.43.0-1ubuntu1) …
Setting up python-software-properties (0.96.20) …
vskumar@ubuntu:/etc/ansible$
===== Installed python properties ======>

Step 5:
Let us check the version:
=== Checking ANSIBLE Version ===>
vskumar@ubuntu:~$ ansible –version
ansible 2.4.3.0
config file = /etc/ansible/ansible.cfg
configured module search path = [u’/home/vskumar/.ansible/plugins/modules’, u’/usr/share/ansible/plugins/modules’]
ansible python module location = /usr/lib/python2.7/dist-packages/ansible
executable location = /usr/bin/ansible
python version = 2.7.12 (default, Dec 4 2017, 14:50:18) [GCC 5.4.0 20160609]
vskumar@ubuntu:~$
=============================>
It means from the above display it is confirmed ansible is available.

Step 6:
The ansible is on the below dir:

======= Check List of files ===>
vskumar@ubuntu:~$ ls -lha /etc/ansible
total 48K
drwxr-xr-x 4 root root 4.0K Mar 6 08:52 .
drwxr-xr-x 142 root root 12K Mar 6 05:59 ..
-rw-r–r– 1 root root 19K Jan 31 15:21 ansible.cfg
drwxr-xr-x 2 root root 4.0K Mar 6 08:59 group_vars
-rw-r–r– 1 root root 1.2K Mar 6 08:20 hosts
drwxr-xr-x 2 root root 4.0K Jan 31 19:46 roles
vskumar@ubuntu:~$
========================>

Step 7:
Always it is better we need to have backup of the above files in a folder.
Now let me copy all of them as below:
Make a backup of all the files as below :
== Making backup ====>

vskumar@ubuntu:~$ sudo cp -R /etc/ansible ansplatform1

vskumar@ubuntu:~$ cd ansplatform1
vskumar@ubuntu:~/ansplatform1$ ls
ansible.cfg group_vars hosts roles
vskumar@ubuntu:~/ansplatform1$
===== Backup files ====>

Step 8:
In the above dir, let us modify ansible.cfg
to have the below line uncommented:
inventory = hosts
====Modifying ansible.cfg ====>
vskumar@ubuntu:~/ansplatform1$ sudo vim ansible.cfg
vskumar@ubuntu:~/ansplatform1$
======>

You can see part of the file as below :
=== Part of config file to update ====>
vskumar@ubuntu:/etc/ansible$ ls
ansible.cfg group_vars hosts roles
vskumar@ubuntu:/etc/ansible$ vim ansible
vskumar@ubuntu:/etc/ansible$
vskumar@ubuntu:/etc/ansible$ vim ansible.cfg
vskumar@ubuntu:/etc/ansible$

Updated line:
inventory = /etc/ansible/hosts

== Updated area only ===>

Step 9:

Configuring Ansible Hosts:
Ansible keeps track of all of the servers.
It knows about them through a “hosts” file.
We need to set up this file first, before we can begin to
communicate with our other computers.
Now let us see the current content of hosts file:
Using : $sudo cat /etc/ansible/hosts

====== The default Contents of hosts file ===>
vskumar@ubuntu:~$ sudo cat /etc/ansible/hosts
# This is the default ansible ‘hosts’ file.
#
# It should live in /etc/ansible/hosts
#
# – Comments begin with the ‘#’ character
# – Blank lines are ignored
# – Groups of hosts are delimited by [header] elements
# – You can enter hostnames or ip addresses
# – A hostname/ip can be a member of multiple groups

# Ex 1: Ungrouped hosts, specify before any group headers.

## green.example.com
## blue.example.com
## 192.168.100.1
## 192.168.100.10

# Ex 2: A collection of hosts belonging to the ‘webservers’ group

## [webservers]
## alpha.example.org
## beta.example.org
## 192.168.1.100
## 192.168.1.110

# If you have multiple hosts following a pattern you can specify
# them like this:

## www[001:006].example.com

# Ex 3: A collection of database servers in the ‘dbservers’ group

## [dbservers]
##
## db01.intranet.mydomain.net
## db02.intranet.mydomain.net
## 10.25.1.56
## 10.25.1.57

# Here’s another example of host ranges, this time there are no
# leading 0s:

## db-[99:101]-node.example.com

vskumar@ubuntu:~$
==================>

We can see a file that has a lot of example configurations,
none of them will actually work for us since these hosts are made up.
So to start with, let’s make sure they all are commented out on the
lines in this file by adding a “#” before each line.

We will keep these examples in the file only as they were to help us with
configuration.

If we want to implement more complex scenarios in the future these can be reused.

After making sure all of these lines are commented,
we can start adding our hosts in the hosts file.
To do our lab exercise;
Now, we need to identify our local hosts.
You can check your laptop or desktop ip as one host.
Another host you consider your ubuntu VM, where the current Ansible is configured.
For now, let us work with two hosts only.
In my systems:
To identify my ubuntu host1:
====== ifconfig =====>

vskumar@ubuntu:~$ ifconfig
docker0 Link encap:Ethernet HWaddr 02:42:06:95:ca:2d
inet addr:172.17.0.1 Bcast:172.17.255.255 Mask:255.255.0.0
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

ens33 Link encap:Ethernet HWaddr 00:0c:29:f8:40:61
inet addr:192.168.116.129 Bcast:192.168.116.255 Mask:255.255.255.0
inet6 addr: fe80::2fed:4aa:a6:34ad/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3621 errors:0 dropped:0 overruns:0 frame:0
TX packets:1342 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:5111534 (5.1 MB) TX bytes:112090 (112.0 KB)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:530 errors:0 dropped:0 overruns:0 frame:0
TX packets:530 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:47656 (47.6 KB) TX bytes:47656 (47.6 KB)

vskumar@ubuntu:~$
=======================>
I need to consider  my base ubuntu VM is as ‘192.168.116.129’
Hence my host1=192.168.116.129 from ens33
You can also check your VM IP.

Now, let me check my local host [laptop] ip:

====== IPCONFIG info from Laptop CMD =====>
Connection-specific DNS Suffix . :
Link-local IPv6 Address . . . . . : fe80::197c:6a85:f86:a3e4%20
IPv4 Address. . . . . . . . . . . : 192.168.137.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
======================>
Let me check the ip connection from my Ubuntu VM.
=== Testing laptop ip from VM ====>
vskumar@ubuntu:~$ ping 192.168.137.1
PING 192.168.137.1 (192.168.137.1) 56(84) bytes of data.
64 bytes from 192.168.137.1: icmp_seq=1 ttl=128 time=3.89 ms
64 bytes from 192.168.137.1: icmp_seq=2 ttl=128 time=1.15 ms
64 bytes from 192.168.137.1: icmp_seq=3 ttl=128 time=1.19 ms
64 bytes from 192.168.137.1: icmp_seq=4 ttl=128 time=1.38 ms
64 bytes from 192.168.137.1: icmp_seq=5 ttl=128 time=1.15 ms
64 bytes from 192.168.137.1: icmp_seq=6 ttl=128 time=1.26 ms
64 bytes from 192.168.137.1: icmp_seq=7 ttl=128 time=1.13 ms
64 bytes from 192.168.137.1: icmp_seq=8 ttl=128 time=1.13 ms
64 bytes from 192.168.137.1: icmp_seq=9 ttl=128 time=1.39 ms
64 bytes from 192.168.137.1: icmp_seq=10 ttl=128 time=1.29 ms
64 bytes from 192.168.137.1: icmp_seq=11 ttl=128 time=1.26 ms
64 bytes from 192.168.137.1: icmp_seq=12 ttl=128 time=1.14 ms
64 bytes from 192.168.137.1: icmp_seq=13 ttl=128 time=1.22 ms
64 bytes from 192.168.137.1: icmp_seq=14 ttl=128 time=1.37 ms
64 bytes from 192.168.137.1: icmp_seq=15 ttl=128 time=1.14 ms
^C
— 192.168.137.1 ping statistics —
15 packets transmitted, 15 received, 0% packet loss, time 14032ms
rtt min/avg/max/mdev = 1.134/1.411/3.899/0.672 ms
vskumar@ubuntu:~$
==========>
Now, I consider my host2 = 192.168.137.1

Let me ping my VM from Laptop CMD:
==== Pinging Ubuntu IP from CMD prompt =====>
C:\Users\Toshiba>ping 192.168.116.129

Pinging 192.168.116.129 with 32 bytes of data:
Reply from 192.168.116.129: bytes=32 time=2ms TTL=64
Reply from 192.168.116.129: bytes=32 time<1ms TTL=64
Reply from 192.168.116.129: bytes=32 time<1ms TTL=64
Reply from 192.168.116.129: bytes=32 time<1ms TTL=64

Ping statistics for 192.168.116.129:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 2ms, Average = 0ms

C:\Users\Toshiba>
====== Replied VM ====>

It means both hosts are working fine.
Now, below block we should add to our hosts file to connect them:

[servers]
host1 ansible_ssh_host=192.168.116.129
host2 ansible_ssh_host=192.168.137.1
We can consider two groups from these two hosts.
Let me check the files as below:
==== List the current files ====>

vskumar@ubuntu:/etc/ansible$ ls -l
total 28
-rw-r–r– 1 root root 19155 Jan 31 15:21 ansible.cfg
-rw-r–r– 1 root root 1016 Jan 31 15:21 hosts
drwxr-xr-x 2 root root 4096 Jan 31 19:46 roles
vskumar@ubuntu:/etc/ansible$
===============================>

Now, let me update the host file.
=== After adding the content of hosts file ===>
vskumar@ubuntu:/etc/ansible$ sudo vim hosts
[sudo] password for vskumar:
Sorry, try again.
[sudo] password for vskumar:
vskumar@ubuntu:/etc/ansible$
vskumar@ubuntu:/etc/ansible$ tail -10 hosts

# Here’s another example of host ranges, this time there are no
# leading 0s:

## db-[99:101]-node.example.com

[servers]
host1 ansible_ssh_host=192.168.116.129
host2 ansible_ssh_host=192.168.137.1
vskumar@ubuntu:/etc/ansible$
== You can see the lst 3 lines of the hosts file ===>

We also need to add the group name as below in the hosts file.

[group_name]
alias ansible_ssh_host=your_server_ip

Here, the group_name is an organizational tag that you will refer to any servers listed
under it with one word.
The alias is just a name to refer to that server.
Now let me add the above lines in hosts above the servers line as below.
[ansible_test1]
alias ansible_ssh_host=192.168.116.129
===== Hosts updated – latest ===>
vskumar@ubuntu:/etc/ansible$ sudo vim hosts
vskumar@ubuntu:/etc/ansible$
vskumar@ubuntu:/etc/ansible$ tail -10 hosts
# leading 0s:

## db-[99:101]-node.example.com
[ansible_test1]
alias ansible_ssh_host=192.168.116.129

[servers]
host1 ansible_ssh_host=192.168.116.129
host2 ansible_ssh_host=192.168.137.1

vskumar@ubuntu:/etc/ansible$
==============================>

Now let me goto ansible dir:
======>
vskumar@ubuntu:~$ cd /etc/ansible
vskumar@ubuntu:/etc/ansible$
======>

Assuming in our Ansible test scenario,
we are imagining that we have two servers we are going to control with Ansible.
These servers are accessible from the Ansible server by typing:
$ssh root@your_server_ip

Means as:
$ssh root@192.168.116.129

==============>
vskumar@ubuntu:/etc/ansible$ ssh root@192.168.116.129
ssh: connect to host 192.168.116.129 port 22: Connection refused
vskumar@ubuntu:/etc/ansible$
==============>
TROUBLE SHOOT THE HOSTS:
=== Trouble shoot ===>
vskumar@ubuntu:/etc/ansible$ ansible -m ping all
host1 | UNREACHABLE! => {
“changed”: false,
“msg”: “Failed to connect to the host via ssh: ssh: connect to host 192.168.116.129 port 22: Connection refused\r\n”,
“unreachable”: true
}
alias | UNREACHABLE! => {
“changed”: false,
“msg”: “Failed to connect to the host via ssh: ssh: connect to host 192.168.116.129 port 22: Connection refused\r\n”,
“unreachable”: true
}
host2 | UNREACHABLE! => {
“changed”: false,
“msg”: “Failed to connect to the host via ssh: \r\n ****USAGE WARNING****\r\n\r\nThis is a private computer system. This computer system, including all\r\nrelated equipment, networks, and network devices (specifically including\r\nInternet access) are provided only for authorized use. This computer system\r\nmay be monitored for all lawful purposes, including to ensure that its use\r\nis authorized, for management of the system, to facilitate protection against\r\nunauthorized access, and to verify security procedures, survivability, and\r\noperational security. Monitoring includes active attacks by authorized entities\r\nto test or verify the security of this system. During monitoring, information\r\nmay be examined, recorded, copied and used for authorized purposes. All\r\ninformation, including personal information, placed or sent over this system\r\nmay be monitored.\r\n\r\nUse of this computer system, authorized or unauthorized, constitutes consent\r\nto monitoring of this system. Unauthorized use may subject you to criminal\r\nprosecution. Evidence of unauthorized use collected during monitoring may be\r\nused for administrative, criminal, or other adverse action. Use of this system\r\nconstitutes consent to monitoring for these purposes.\r\n\r\n\r\nPermission denied (publickey,password,keyboard-interactive).\r\n”,
“unreachable”: true
}
vskumar@ubuntu:/etc/ansible$
===============>
The reason for the above error is;
With our current settings, we tried to connect to any of these hosts with Ansible,
the command failed.
This is because your SSH key is embedded for the root user on the remote systems
and Ansible will by default try to connect as your current user.
A connection attempt will get the above error.

To rectify it;
We can create a file that tells all of the servers in the “servers” group to connect
using the root user.

To do this, we will create a directory in the Ansible configuration structure called group_vars.
Let us use the below dir commands:
$sudo mkdir /etc/ansible/group_vars

========================>
vskumar@ubuntu:/etc/ansible$ sudo mkdir /etc/ansible/group_vars
vskumar@ubuntu:/etc/ansible$ ls -l
total 32
-rw-r–r– 1 root root 19155 Jan 31 15:21 ansible.cfg
drwxr-xr-x 2 root root 4096 Mar 6 08:52 group_vars
-rw-r–r– 1 root root 1158 Mar 6 08:20 hosts
drwxr-xr-x 2 root root 4096 Jan 31 19:46 roles
vskumar@ubuntu:/etc/ansible$
=================>
Within this folder, we can create YAML-formatted files for each group we want to configure.
By using below command:
$sudo vim /etc/ansible/group_vars/servers
We can put our configuration in here. YAML files start with “—“, so make sure you don’t forget that part.

Below Code:

ansible_ssh_user: root

==========>
udo vim /etc/ansible/group_vars/servers
vskumar@ubuntu:/etc/ansible$ cat /etc/ansible/group_vars/servers


ansible_ssh_user: root
vskumar@ubuntu:/etc/ansible$
=======================>

NOTE:
If you want to specify configuration details for every server, regardless of group association, you can put those details in a file at: 

/etc/ansible/group_vars/all.

Individual hosts can be configured by creating files under a directory at: /etc/ansible/host_vars.

Assuming this helped you to configure your Ansible.

Please leave your positive comment for others also to follow.

You can see next blog on ssh setup and usage from the below url:

https://vskumar.blog/2018/05/26/27-devopsworking-with-ssh-for-ansible-usage/

I have made a video for Ansible installation using Ubuntu 18.04 VM:

16. DevOps: Working with Git on Ubuntu 16.04 VM

Git-logo

In this GIT exercise, I would like to present the below lab sessions for git in an Ubuntu 16.04 VM for the people who attended my sessions so far.
1. How to install git in ubuntu [linux] ?:
2. How To Set Up Git ?:
3. How to check the config file content? :
4. How to clone a project from an url ?:
5. How to Create a test dir or folder for git project?:
6. How initiate the git for the current folder or dir in linux ?:
7. How to Create local files and check the status in the current git folder?:
8. How to commit the files into a local repository and check their status ?:
9. How to commit files into local repo with a message ?:
10. How to check the history of the local git repository ?:
11. How to identify the difference of two commit ids ?:
12. How to check and operate the staged files in local repository ?:
13. What are the ultimate format of the git log ?:
14. How to setup aliases for different git commands?:
15. How to use tags and operate for different versions in a repository?:
16. How to revert back the changes to older version ?:
17. How to cancel the committed changes? :
18. How to reset the reverted changes through commit from the branch? :

19. Working with git directory:

     20. Working with git branches and master :

     21. How to Merge latest objects into single branch ?:

 

1. How to install git in ubuntu [linux] ?:

$sudo apt-get update

$sudo apt-get install git

2. How To Set Up Git ?:
$git config –global user.name “Your Name”

$git config –global user.email “youremail@domain.com”

Ex:
git config –global user.kumar2018 “Vskumar”
git config –global user.email “vskumar35@gmail.com”

==== Screen output for the above commands==>
vskumar@ubuntu:~$ git config –global user.kumar2018 “Vskumar”
vskumar@ubuntu:~$ git config –global user.email “vskumar35@gmail.com”
vskumar@ubuntu:~$ git config –list
user.kumar2018=Vskumar
user.email=vskumar35@gmail.com
vskumar@ubuntu:~$
===========>
3. How to check the config file content? :

$cat ~/.gitconfig
==== Output of config file ===>
vskumar@ubuntu:~$ cat ~/.gitconfig
[user]
kumar2018 = Vskumar
email = vskumar35@gmail.com
vskumar@ubuntu:~$
=============>

4. How to clone a project from an url ?: Let us clone one project as below:
$git clone https://github.com/vskumar2017/VSKTestproject1

=== Screen outout ==>
vskumar@ubuntu:~$
vskumar@ubuntu:~$ sudo git clone https://github.com/vskumar2017/VSKTestproject1
Cloning into ‘VSKTestproject1’…
remote: Counting objects: 57, done.
remote: Total 57 (delta 0), reused 0 (delta 0), pack-reused 57
Unpacking objects: 100% (57/57), done.
Checking connectivity… done.
vskumar@ubuntu:~$
vskumar@ubuntu:~$ ls
data-volume1 examples.desktop Pictures VSKTestproject1
Desktop flask-test Public
Documents jdk-9.0.4_linux-x64_bin.tar.gz Templates
Downloads Music Videos
vskumar@ubuntu:~$
=====================>
5. How to Create a test dir or folder for git project?:

=============>
vskumar@ubuntu:~$ mkdir test-git
vskumar@ubuntu:~$ pwd
/home/vskumar
vskumar@ubuntu:~$ ls
data-volume1 examples.desktop Pictures Videos
Desktop flask-test Public VSKTestproject1
Documents jdk-9.0.4_linux-x64_bin.tar.gz Templates
Downloads Music test-git
vskumar@ubuntu:~$
vskumar@ubuntu:~$
vskumar@ubuntu:~$ cd test-git
vskumar@ubuntu:~/test-git$ ls
vskumar@ubuntu:~/test-git$
=======>
6. How initiate the git for the current folder or dir in linux ?:
== Initialize the current dir for git init===>
vskumar@ubuntu:~/test-git$ git init
Initialized empty Git repository in /home/vskumar/test-git/.git/
vskumar@ubuntu:~/test-git$
========>

7. How to Create local files and check the status in the current git folder?:
== Create a text file========>
vskumar@ubuntu:~/test-git$ echo “Testing line1 for git ..” >> test1.txt vskumar@ubuntu:~/test-git$ cat test1.txt Testing line1 for git .. vskumar@ubuntu:~/test-git$ ls -l
total 4
-rw-rw-r– 1 vskumar vskumar 25 Feb 24 04:03 test1.txt

vskumar@ubuntu:~/test-git$ git status On branch master Initial commit Untracked files: (use “git add <file>…” to include in what will be committed) test1.txt nothing added to commit but untracked files present (use “git add” to track) vskumar@ubuntu:~/test-git$
===== Add a new file====>
vskumar@ubuntu:~/test-git$ git add test1.txt
vskumar@ubuntu:~/test-git$ git status
On branch master
Initial commit

Changes to be committed:
(use “git rm –cached <file>…” to unstage)

new file: test1.txt

vskumar@ubuntu:~/test-git$

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

8. How to commit the files into a local repository and check their status ?:

Now, let us do simple commit the file to the local repo.

$git commit -m “First Commit”
=== Commite output ==>
vskumar@ubuntu:~/test-git$ git commit -m “First Commit”
[master (root-commit) 56ccc1e] First Commit
1 file changed, 1 insertion(+)
create mode 100644 test1.txt
vskumar@ubuntu:~/test-git$
======================>
We can check the current status:

=== status after commit ===>
vskumar@ubuntu:~/test-git$ git status
On branch master
nothing to commit, working directory clean
vskumar@ubuntu:~/test-git$
==========>

== Added a new message ===>
vskumar@ubuntu:~/test-git$ echo ‘Testing line2 for git—->’ >> test1.txt
vskumar@ubuntu:~/test-git$ cat test1.txt
Testing line1 for git ..
Testing line2 for git—->
vskumar@ubuntu:~/test-git$
===============>

=== Current status ===>
vskumar@ubuntu:~/test-git$ git status
On branch master
Changes not staged for commit:
(use “git add <file>…” to update what will be committed)
(use “git checkout — <file>…” to discard changes in working directory)

modified: test1.txt

no changes added to commit (use “git add” and/or “git commit -a”)
vskumar@ubuntu:~/test-git$
=====================>
Now, add these two files:
git add test1.txt
git add test2.txt

=== Add and check status for two files ==>
vskumar@ubuntu:~/test-git$ git add test1.txt
vskumar@ubuntu:~/test-git$ git add test2.txt
vskumar@ubuntu:~/test-git$ git status
On branch master
Changes to be committed:
(use “git reset HEAD <file>…” to unstage)

modified: test1.txt
new file: test2.txt

vskumar@ubuntu:~/test-git$
====================================>
9. How to commit files into local repo with a message ?:

Commit these two files:

git commit -m “Committed:Changes for test1.txt and test2.txt”

==== Committed changes and status ===>
vskumar@ubuntu:~/test-git$ git commit -m “Committed:Changes for test1.txt and test2.txt”
[master 2a7192d] Committed:Changes for test1.txt and test2.txt
2 files changed, 2 insertions(+)
create mode 100644 test2.txt
vskumar@ubuntu:~/test-git$ git status
On branch master
nothing to commit, working directory clean
vskumar@ubuntu:~/test-git$
======================================>

Now, let us test the add command . prompt by having 2 or more files.

=== Updated two files ==>
vskumar@ubuntu:~/test-git$ cat test1.txt
Testing line1 for git ..
Testing line2 for git—->
Testing test1.tx for add . function
vskumar@ubuntu:~/test-git$ cat test2.txt
File Test2: Testing for Git commit –>
Testing test2.tx for add . function
vskumar@ubuntu:~/test-git$
=============>
Let us check the status:
==== Status ==>

vskumar@ubuntu:~/test-git$ git status
On branch master
Changes not staged for commit:
(use “git add <file>…” to update what will be committed)
(use “git checkout — <file>…” to discard changes in working directory)

modified: test1.txt
modified: test2.txt

no changes added to commit (use “git add” and/or “git commit -a”)
vskumar@ubuntu:~/test-git$
===============>

Now to add these two file together we need to use ‘git addd .’
== Added all files ===>
vskumar@ubuntu:~/test-git$
vskumar@ubuntu:~/test-git$ git add .
vskumar@ubuntu:~/test-git$ git status
On branch master
Changes to be committed:
(use “git reset HEAD <file>…” to unstage)

modified: test1.txt
modified: test2.txt

vskumar@ubuntu:~/test-git$
============>
Now let us commit the changes of one file at a time.

=== test1.txt commitment===>
vskumar@ubuntu:~/test-git$ git commit test1.txt -m ‘Committed test1.txt 3rd change’
[master 6bfd9b0] Committed test1.txt 3rd change
1 file changed, 1 insertion(+)
vskumar@ubuntu:~/test-git$ ^C
============================>
Now, let us check the status:

=======>
vskumar@ubuntu:~/test-git$
vskumar@ubuntu:~/test-git$ git status
On branch master
Changes to be committed:
(use “git reset HEAD <file>…” to unstage)

modified: test2.txt

vskumar@ubuntu:~/test-git$
========>
In git we can check the history by using ‘git log’ command.

=== Histroy ====>
vskumar@ubuntu:~/test-git$ git log
commit 69282e8d8c07e7cbc68e93b16df1d943d3b518d5
Author: Vsk <vskumar35@gmail.com>
Date: Sat Feb 24 06:49:27 2018 -0800

Committed test2.txt 3rd change

commit 6bfd9b045c352f13c36d8f82f12567058a8bb468
Author: Vsk <vskumar35@gmail.com>
Date: Sat Feb 24 06:46:24 2018 -0800

Committed test1.txt 3rd change

commit 2a7192dcdd1a123b8164f0d48dd0631645cf0630
Author: Vsk <vskumar35@gmail.com>
Date: Sat Feb 24 06:32:03 2018 -0800

Committed:Changes for test1.txt and test2.txt

commit 56ccc1ec9ae7db9f97e3a08e5488a64b4f130f1b
Author: Vsk <vskumar35@gmail.com>
Date: Sat Feb 24 06:08:42 2018 -0800

First Commit
vskumar@ubuntu:~/test-git$
=====================>
10. How to check the history of the local git repository ?:

In git we can check the history by using ‘git log’ command. It can give entire committed history with the relevant comments. If we use ‘git log –pretty=oneline’ it gives only chekcsums for different times commited occasions with commit the messages.

If we use ‘git log –pretty=oneline’ it gives only chekcsums for different times commited occasions with commit the messages.

=== Output for pretty ===>
vskumar@ubuntu:~/test-git$ git log –pretty=oneline
69282e8d8c07e7cbc68e93b16df1d943d3b518d5 Committed test2.txt 3rd change
6bfd9b045c352f13c36d8f82f12567058a8bb468 Committed test1.txt 3rd change
2a7192dcdd1a123b8164f0d48dd0631645cf0630 Committed:Changes for test1.txt and test2.txt
56ccc1ec9ae7db9f97e3a08e5488a64b4f130f1b First Commit
vskumar@ubuntu:~/test-git$
==============>

We can also check the commitments by author also using
‘git log –pretty=oneline –author=<your name>’

git log –pretty=oneline –author=kumar

============>
vskumar@ubuntu:~/test-git$ git log –pretty=oneline –author=kumar
69282e8d8c07e7cbc68e93b16df1d943d3b518d5 Committed test2.txt 3rd change
6bfd9b045c352f13c36d8f82f12567058a8bb468 Committed test1.txt 3rd change
2a7192dcdd1a123b8164f0d48dd0631645cf0630 Committed:Changes for test1.txt and test2.txt
56ccc1ec9ae7db9f97e3a08e5488a64b4f130f1b First Commit
============>
Let me give wrong user name to test:
=== Wrong user name ====>
vskumar@ubuntu:~/test-git$ git log –pretty=oneline –author=kumar1
vskumar@ubuntu:~/test-git$ git log –pretty=oneline –author=kumar202
vskumar@ubuntu:~/test-git$
= No files committed for the above users ==>

We can see more detail about a particular commit through show command.
The command ‘git log’ yields a sequential history of the individual commits within the repository.
Then you need to collect the commit id.

=== git show =====>
vskumar@ubuntu:~/test-git$ git show 56ccc1ec9ae7db9f97e3a08e5488a64b4f130f1b
commit 56ccc1ec9ae7db9f97e3a08e5488a64b4f130f1b
Author: Vsk <vskumar35@gmail.com>
Date: Sat Feb 24 06:08:42 2018 -0800

First Commit

diff –git a/test1.txt b/test1.txt
new file mode 100644
index 0000000..73b0484
— /dev/null
+++ b/test1.txt
@@ -0,0 +1 @@
+Testing line1 for git ..
vskumar@ubuntu:~/test-git$
=============================>
11. How to identify the difference of two commit ids ?:
The diff command recalls both full commit ID names and run ‘git diff’

git diff 2a7192dcdd1a123b8164f0d48dd0631645cf0630 6bfd9b045c352f13c36d8f82f12567058a8bb468

== Output of two commit diffs ==>
vskumar@ubuntu:~/test-git$ git diff 2a7192dcdd1a123b8164f0d48dd0631645cf0630 6bfd9b045c352f13c36d8f82f12567058a8bb468
diff –git a/test1.txt b/test1.txt
index 931bb8b..b9132c1 100644
— a/test1.txt
+++ b/test1.txt
@@ -1,2 +1,3 @@
Testing line1 for git ..
Testing line2 for git—->
+Testing test1.tx for add . function
vskumar@ubuntu:~/test-git$
==============================>
12. How to check and operate the staged files in local repository ?:

We can use the below command:
git ls-files –stage

=== Stage of current files ===>
vskumar@ubuntu:~/test-git$
vskumar@ubuntu:~/test-git$ git ls-files –stage
100644 b9132c1dd4ac08fa9c1e3dea5d7100e33557ad20 0 test1.txt
100644 0866cfd2c7ac9bf17f0a0590551a3580359e7250 0 test2.txt
vskumar@ubuntu:~/test-git$
========================>
=== Rm and later files stage ==>
vskumar@ubuntu:~/test-git$ git rm –cached test1.txt
rm ‘test1.txt’
vskumar@ubuntu:~/test-git$ git ls-files –stage
100644 0866cfd2c7ac9bf17f0a0590551a3580359e7250 0 test2.txt
vskumar@ubuntu:~/test-git$
vskumar@ubuntu:~/test-git$ git rm –cached test1.txt
rm ‘test1.txt’
vskumar@ubuntu:~/test-git$ git ls-files –stage
100644 0866cfd2c7ac9bf17f0a0590551a3580359e7250 0 test2.txt
vskumar@ubuntu:~/test-git$
=====>
You can see the removed file is back into dir:
== Status of removed file ==>
vskumar@ubuntu:~/test-git$ git status
On branch master
Changes to be committed:
(use “git reset HEAD <file>…” to unstage)
deleted: test1.txt
Untracked files:
(use “git add <file>…” to include in what will be committed)

test1.txt
vskumar@ubuntu:~/test-git$
=== It need to be be added and committed ====>
vskumar@ubuntu:~/test-git$ git add .
vskumar@ubuntu:~/test-git$ git status
On branch master
nothing to commit, working directory clean
vskumar@ubuntu:~/test-git$
======= It need to be added only===.

====== list the stage files =>
vskumar@ubuntu:~/test-git$
vskumar@ubuntu:~/test-git$ git ls-files –stage
100644 b9132c1dd4ac08fa9c1e3dea5d7100e33557ad20 0 test1.txt
100644 0866cfd2c7ac9bf17f0a0590551a3580359e7250 0 test2.txt
vskumar@ubuntu:~/test-git$
=========================>
13. What are the ultimate format of the git log ?:
We can use the ultimate format of the log as: git log –pretty=format:”%h %ad | %s%d [%an]” –graph –date=short

===== Screen output ==========>
vskumar@ubuntu:~$ cd test-git vskumar@ubuntu:~/test-git$ pwd /home/vskumar/test-git vskumar@ubuntu:~/test-git$ git log –pretty=format:”%h %ad | %s%d [%an]” –graph –date=short * 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master) [Vsk] * 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk] * 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk] * 56ccc1e 2018-02-24 | First Commit [Vsk] vskumar@ubuntu:~/test-git$

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

14. How to setup aliases for different git commands?:

If there is a common and complex the Git command you type frequently, consider setting up a simple Git alias for it.

We can use the below common aliases:

git config –global alias.ci commit

git config –global alias.st status

git config –global alias.br branch

git config –global alias.hist “log –pretty=format:’%h %ad | %s%d [%an]’ –graph –date=short”

Once you setup the above aliases for git commands you need to use them only, instead of commands.

Like; for command: ‘log –pretty=format:’%h %ad | %s%d [%an]’ –graph –date=short You need to use git hist, etc.

You also need to remember them well. Once you setup the above aliases for git commands you need to use them only instead of commands.

Like; for command: ‘log –pretty=format:”%h %ad | %s%d [%an]” –graph –date=short’

You need to use git hist, etc. You also need to remember them well.

Let us try one command for branch:

===== Screen output ==========>

vskumar@ubuntu:~$ cd test-git

vskumar@ubuntu:~/test-git$ pwd /home/vskumar/test-git

vskumar@ubuntu:~/test-git$ git log –pretty=format:”%h %ad | %s%d [%an]” –graph –date=short

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master) [Vsk]

*6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk] vskumar@ubuntu:~/test-git$ ==========================>

=== History =======>

vskumar@ubuntu:~/test-git$ git log –pretty=format:”%h %ad | %s%d [%an]” –graph –date=short

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$ git config –global alias.hist “log –pretty=format:’%h %ad | %s%d [%an]’ –grap h –date=short”

==== With alias hist ========>

vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

15. How to use tags and operate for different versions in a repository?:

Tags for previous versions of git: W

We can tag latest committed versions from a local repo to reuse them later stages. Let’s tag the version prior to the current version with the name v1.

First, we will checkout the previous version. Instead of looking up the hash, we are going to use the  notation indicating “the parent of v1”. git tag v1

=== You can see the tagging process for the latest commit ===>

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$ git tag v1

vskumar@ubuntu:~/test-git$ git checkout v1

Note: checking out ‘v1’. You are in ‘detached HEAD’ state. You can look around, make experimental changes and commit them, and you can discard any commits you make in this state without impacting any branches by performing another checkout. If you want to create a new branch to retain commits you create, you may do so (now or later) by using -b with the checkout command again. Example: git checkout -b <new-branch-name> HEAD is now at 69282e8… Committed test2.txt 3rd change

vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD, tag: v1, master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$ git status

HEAD detached at v1 nothing to commit, working directory clean vskumar@ubuntu:~/test-git$

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

Now, let us add a line to test1.txt and commit it.

===== Screen output ===>

vskumar@ubuntu:~/test-git$ ls -l total 8

-rw-rw-r– 1 vskumar vskumar 88 Feb 24 06:37 test1.txt

-rw-rw-r– 1 vskumar vskumar 75 Feb 24 06:37 test2.txt

vskumar@ubuntu:~/test-git$ git status

HEAD detached at v1 nothing to commit, working directory clean vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ echo ‘Testing test1.txt for tagging v2’ >> test1.txt vskumar@ubuntu:~/test-git$ cat test1.txt

Testing line1 for git .. Testing line2 for git—->

Testing test1.tx for add . function

Testing test1.txt for tagging v2

vskumar@ubuntu:~/test-git$ git status

HEAD detached at v1 Changes not staged for commit: (use “git add <file>…” to update what will be committed) (use “git checkout — <file>…” to discard changes in working directory) modified: test1.txt no changes added to commit (use “git add” and/or “git commit -a”)

vskumar@ubuntu:~/test-git$

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

Now let me add and commit

=== Add and commit for tagging 2nd time ===>

vskumar@ubuntu:~/test-git$ git add .

vskumar@ubuntu:~/test-git$ git status

HEAD detached at v1 Changes to be committed: (use “git reset HEAD <file>…” to unstage) modified: test1.txt

vskumar@ubuntu:~/test-git$ git commit -m ‘Added for tagging 2nd time’

[detached HEAD 0bec7c0] Added for tagging 2nd time 1 file changed, 1 insertion(+) vskumar@ubuntu:~/test-git$ git status HEAD detached from v1 nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$

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

Now, let us tag 2nd time :

== You can see two versions are tagged ===>

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ git hist

* 0bec7c0 2018-02-24 | Added for tagging 2nd time (HEAD) [Vsk]

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1, master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$ git tag v2

vskumar@ubuntu:~/test-git$ git hist

* 0bec7c0 2018-02-24 | Added for tagging 2nd time (HEAD, tag: v2) [Vsk]

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1, master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

Now let us check the latest version of test1.txt content.

=== Latest version test1.txt ===>

vskumar@ubuntu:~/test-git$ ls -l

total 8 -rw-rw-r– 1

vskumar vskumar 121 Feb 24 20:58 test1.txt -rw-rw-r– 1 vskumar vskumar 75 Feb 24 06:37 test2.txt

vskumar@ubuntu:~/test-git$ cat test1.txt

Testing line1 for git .. Testing line2 for git—-> Testing test1.tx for add . function Testing test1.txt for tagging v2

vskumar@ubuntu:~/test-git$

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

Now, let us checkout the older version to test the content of test1.txt. using : git checkout v1

====== Chekout v1 to track changes ====>

vskumar@ubuntu:~/test-git$ git checkout v1

Previous HEAD position was 0bec7c0… Added for tagging 2nd time HEAD is now at 69282e8… Committed test2.txt 3rd change

vskumar@ubuntu:~/test-git$ cat test1.txt

Testing line1 for git .. Testing line2 for git—->

Testing test1.tx for add . function

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ git status

HEAD detached at v1 nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$

=== We can see the older version content only===>

===== We can see the hist and make the current master checkout s v1 ===> vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD, tag: v1, master) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ git checkout

master Switched to branch ‘master’

vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master, tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk] vskumar@ubuntu:~/test-git$ vskumar@ubuntu:~/test-git$ git status On branch master nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$

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

16. How to revert back the changes to older version ?:

Now, let us understand on how to revertback the changes in a local file.

We can use reset command to bring back the previous version. If you have a modified object in the working dir and want to revertback to older version you can follow the below steps.

The reset command resets the buffer zone to HEAD. This clears the buffer zone from the changes that we have just staged. The reset command (default) does not change the working directory. Hence, the working directory still contains unwanted comments.

We can use the checkout command from the previous tutorial to remove unwanted changes from working directory.

===== to revertback Reset the modified file and checkout that file only =====> vskumar@ubuntu:~/test-git$ git status On branch master nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$ echo ‘Testing for reset Head command’ >> test1.txt vskumar@ubuntu:~/test-git$ git status On branch master Changes not staged for commit: (use “git add <file>…” to update what will be committed) (use “git checkout — <file>…” to discard changes in working directory) modified: test1.txt no changes added to commit (use “git add” and/or “git commit -a”)

vskumar@ubuntu:~/test-git$ git reset HEAD test1.txt Unstaged changes after reset: M test1.txt

vskumar@ubuntu:~/test-git$ git status On branch master Changes not staged for commit: (use “git add <file>…” to update what will be committed) (use “git checkout — <file>…” to discard changes in working directory) modified: test1.txt no changes added to commit (use “git add” and/or “git commit -a”)

vskumar@ubuntu:~/test-git$

=== Finally, You can see the older version contents only ====>

17. How to cancel the committed changes? :

We have seen on how to cancel the modified files.

Now we can check on how to revert back the committed changes in the local git repo.

== Let us see the current hist ===>

vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD -> master, tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

Now let us consider v1 to revert back.

We need to use command:git revert HEAD. When we use this command it will open a editor by showing the details.

We can save it using ‘wq!’ like in vi/vim.

===== Output =======>

vskumar@ubuntu:~/test-git$ git revert HEAD

[master fdc40ac] Revert “Committed test2.txt 3rd change” 1 file changed, 1 deletion(-)

vskumar@ubuntu:~/test-git$

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

Now, let us check hist

=== git hist ====>

vskumar@ubuntu:~/test-git$ git hist

* fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” (HEAD -> master) [Vsk]

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

============ Exercise ====================>

If you want to can do an Exercise: You can checkout the committed version. You can add a test to text1 file and commit it. Again you can use the same lab practice.

============ You can revert back also =====>

18. How to reset the reverted changes through commit from the branch? :

Check the previous screen display for the usage of revert command.

Now, if we have decided to reset the changes we can use the command: ‘git reset –hard v1’

=== Screen output for resetting reverted commit=====>

vskumar@ubuntu:~/test-git$ git reset –hard v1

HEAD is now at 69282e8 Committed test2.txt 3rd change

vskumar@ubuntu:~/test-git$ git hist

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD, tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

We can check the committed history using the below command: git hist –all

==== Screen output git hist –all ===>

vskumar@ubuntu:~/test-git$ git hist –all

* fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” (master) [Vsk] |

* 0bec7c0 2018-02-24 | Added for tagging 2nd time (tag: v2) [Vsk] |

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD, tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

You can also observe the reverted information.

We can also drop the tags as below: git tag -d v1

===== Output for tag removal ====>

vskumar@ubuntu:~/test-git$ git tag -d v2

Deleted tag ‘v2’ (was 0bec7c0)

vskumar@ubuntu:~/test-git$ git hist –all

* fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” (master) [Vsk]

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (HEAD, tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

==========So, now v2 tag is removed ========>

You can also see the config file as below:

=== Config file ====>

vskumar@ubuntu:~/test-git$ cat .git/config

[core] repositoryformatversion = 0 filemode = true bare = false logallrefupdates = true vskumar@ubuntu:~/test-git$

=====This configuration file is created for each individual project.===============>

19. Working with git directory:

 

Every Git project will have directories and files.

We can see the git dir items:

==================== Git dir items ===>

vskumar@ubuntu:~/test-git$ ls -l -C .git

branches        config       HEAD   index  logs     ORIG_HEAD

COMMIT_EDITMSG  description  hooks  info   objects  refs

vskumar@ubuntu:~/test-git$

======Root folder of git project =====>

 

We can explore the objects dir to check the objects details.

using ls -l -C .git/objects

 

==== Output ====>

vskumar@ubuntu:~/test-git$ ls -l -C .git/objects

07  0b  44  4f  68  6b  92  b0  bd  fd    pack

08  2a  47  56  69  73  93  b9  e0  info

vskumar@ubuntu:~/test-git$

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

 

We can see a lot of folders named with two characters.

The first two letters sha1 hash of the object stored in git are the directory names.

 

What is SHA1 ?:

The SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function.  

It takes an input and produces a 160-bit (20-byte) hash value known as a message digest to the object.

Typically it is rendered as a hexadecimal number, with 40 digits long.

 

Now, let us see it by inquiring our database objects from the above listed items:

Using the below command we can check the files in dir.

ls -C .git/objects/<dir>   — The dir is the two characters of the above shown values.

==== Checking one dir ====>

vskumar@ubuntu:~/test-git$ ls -l  -C .git/objects/07

5e722b3161a24fd5adcefb574b5360118abbef

vskumar@ubuntu:~/test-git$ ls -l  -C .git/objects/92

d62ee30d26c444d85b3d81a4e2b8b69e0f093f

vskumar@ubuntu:~/test-git$

==== You can see 40 digits size hexadecimal value of objects in 07 and 92 objects dir====>

 

Note, we have seen the config file from the previous exercises.

Now, We will check the branches and tags as below commands:

 

ls .git/refs

ls .git/refs/heads

ls .git/refs/tags

cat .git/refs/tags/v1

 

== Checking branches and tags ===>

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ ls .git/refs

heads  tags

vskumar@ubuntu:~/test-git$ ls .git/refs/heads

master

vskumar@ubuntu:~/test-git$ ls .git/refs/tags

v1

vskumar@ubuntu:~/test-git$ cat .git/refs/tags/v1

69282e8d8c07e7cbc68e93b16df1d943d3b518d5

vskumar@ubuntu:~/test-git$

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

 

Let us note;  each file corresponds to the tag previously created using the git tag command.

Its content is a hash commit attached to the tag.

We have only one branch, and everything we see here in this folder is a master branch.

Now, let us check what the HEAD file contains?:

using :cat .git/HEAD

 

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

vskumar@ubuntu:~/test-git$ cat .git/HEAD

683ed74fda585e10f38111ebb4c84026d5678290

vskumar@ubuntu:~/test-git$

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

 

Let us search for the last committed items:

We can explore the structure of the database objects

using SHA1 hashes for searching the content in the repository.

 

The below command should find the last commit in the repository.

======= SHA hash of git hist ==>

vskumar@ubuntu:~/test-git$ git hist –max-count=1

* 683ed74 2018-02-24 | Added updated test1.txt (HEAD) [Vsk]

vskumar@ubuntu:~/test-git$

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

SHA1 hash is probably different on our systems from this git format.

Now, let us check the last commit details.

Using the below commands:

git cat-file -t <hash>

git cat-file -p <hash>

 

==== SHA1 content and the tree details ===>

vskumar@ubuntu:~/test-git$ git cat-file -t 683ed74

commit

vskumar@ubuntu:~/test-git$ git cat-file -p 683ed74

tree 44298909c5e8873c5870f9f1ca77951ea4e028eb

parent 69282e8d8c07e7cbc68e93b16df1d943d3b518d5

author Vsk <vskumar35@gmail.com> 1519544092 -0800

committer Vsk <vskumar35@gmail.com> 1519544092 -0800

Added updated test1.txt

vskumar@ubuntu:~/test-git$

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

Now, we can display the tree referenced in the above commit.

Using :git cat-file -p <treehash>

From the couple of characters shown for tree.

====== We can see the real files stored under git blob ====>

vskumar@ubuntu:~/test-git$ git cat-file -p 44298909

100644 blob 075e722b3161a24fd5adcefb574b5360118abbef test1.txt

100644 blob 0866cfd2c7ac9bf17f0a0590551a3580359e7250 test2.txt

vskumar@ubuntu:~/test-git$

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

 

== See the contents for text1.txt also ===>

vskumar@ubuntu:~/test-git$ git cat-file -p 075e722b

Testing line1 for git ..

Testing line2 for git—->

Testing test1.tx for add . function

Checking for changing commit comment

vskumar@ubuntu:~/test-git$

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

 

So we have seen the main branch to till the object content level.

 

20. Working with git branches and master :

 

Now, let us see the branches operation. We can create different branches as each developer

can have his/her own branch while working with the same or different objects.

Let us see the current statusof git project:

=========>

vskumar@ubuntu:~/test-git$ pwd

/home/vskumar/test-git

vskumar@ubuntu:~/test-git$ git status

HEAD detached from v1

Changes not staged for commit:

  (use “git add <file>…” to update what will be committed)

  (use “git checkout — <file>…” to discard changes in working directory)

 

modified:   test1.txt

modified:   test2.txt

 

Untracked files:

  (use “git add <file>…” to include in what will be committed)

 

class

test1.class

test1.java

 

no changes added to commit (use “git add” and/or “git commit -a”)

vskumar@ubuntu:~/test-git$

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

 

Now, Let us create a new branch as below [using checkout] and test the operations.

 

git checkout -b testgitbr1

git status

 

====== We are just copied the same project as a branch ======>

vskumar@ubuntu:~/test-git$ git checkout -b testgitbr1

M test1.txt

M test2.txt

Switched to a new branch ‘testgitbr1’

vskumar@ubuntu:~/test-git$ git status

On branch testgitbr1

Changes not staged for commit:

  (use “git add <file>…” to update what will be committed)

  (use “git checkout — <file>…” to discard changes in working directory)

 

modified:   test1.txt

modified:   test2.txt

 

Untracked files:

  (use “git add <file>…” to include in what will be committed)

 

class

test1.class

test1.java

 

no changes added to commit (use “git add” and/or “git commit -a”)

vskumar@ubuntu:~/test-git$

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

Assume a developer want to add his own program.

Now, I would like to add the test1.java program into this new branch:

======= Adding new file ====>

vskumar@ubuntu:~/test-git$ git add test1.java

vskumar@ubuntu:~/test-git$ git status

On branch testgitbr1

Changes to be committed:

  (use “git reset HEAD <file>…” to unstage)

 

new file:   test1.java

 

Changes not staged for commit:

  (use “git add <file>…” to update what will be committed)

  (use “git checkout — <file>…” to discard changes in working directory)

 

modified:   test1.txt

modified:   test2.txt

 

Untracked files:

  (use “git add <file>…” to include in what will be committed)

 

class

test1.class

 

vskumar@ubuntu:~/test-git$

=== New branch has a java program also ===>

Now, let me commit this file with a message:

 

git commit -m “Added a java program [test1.java] to new branch”

 

========>

vskumar@ubuntu:~/test-git$ git commit -m “Added a java program [test1.java] to new branch”

[testgitbr1 4e7baf8] Added a java program [test1.java] to new branch

 1 file changed, 11 insertions(+)

 create mode 100644 test1.java

vskumar@ubuntu:~/test-git$

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

Let us see the status:

 

=== Current status ====>

vskumar@ubuntu:~/test-git$ git status

On branch testgitbr1

Changes not staged for commit:

  (use “git add <file>…” to update what will be committed)

  (use “git checkout — <file>…” to discard changes in working directory)

 

modified:   test1.txt

modified:   test2.txt

 

Untracked files:

  (use “git add <file>…” to include in what will be committed)

 

class

test1.class

 

no changes added to commit (use “git add” and/or “git commit -a”)

vskumar@ubuntu:~/test-git$

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

Now let me add all the modified files also with a commit:

 

=======>

vskumar@ubuntu:~/test-git$ git add .

vskumar@ubuntu:~/test-git$ git status

On branch testgitbr1

Changes to be committed:

  (use “git reset HEAD <file>…” to unstage)

 

new file:   class

new file:   test1.class

modified:   test1.txt

modified:   test2.txt

 

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ git commit -m “Added all 4 files [2-new and 2 modified]”

 

[testgitbr1 26b971b] Added all 4 files [2-new and 2 modified]

 4 files changed, 14 insertions(+), 4 deletions(-)

 create mode 100644 class

 create mode 100644 test1.class

 mode change 100644 => 100755 test1.txt

 mode change 100644 => 100755 test2.txt

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ git status

On branch testgitbr1

nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$

== So, we have updated the new branch ====>

 

Now we need to navigate the available branches.

Let us apply git hist command and check the history as below:

== Checking the git project repo history ====>

vskumar@ubuntu:~/test-git$ git hist

* 26b971b 2018-03-05 | Added all 4 files [2-new and 2 modified] (HEAD -> testgitbr1) [Vsk]

* 4e7baf8 2018-03-05 | Added a java program [test1.java] to new branch [Vsk]

* 683ed74 2018-02-24 | Added updated test1.txt [Vsk]

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

== You can see the latest branch and commit messages===>

Now, let us toggle or do workaround between the branch and the master as below:

Please note so far we are with the testgitbr1 which is  branch.

Now let us use master as below:

git checkout master

==== Master ====>

vskumar@ubuntu:~/test-git$ git checkout master

Switched to branch ‘master’

vskumar@ubuntu:~/test-git$ git status

On branch master

nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$

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

 

Let us check some files and their content:

=== Checking master ===>

 vskumar@ubuntu:~/test-git$ cat test1.txt

Testing line1 for git ..

Testing line2 for git—->

Testing test1.tx for add . function

vskumar@ubuntu:~/test-git$ cat test1.java

cat: test1.java: No such file or directory

vskumar@ubuntu:~/test-git$

==========>

 

Now, let us switch to branch and check the files:

== You can see the difference from master ====>

vskumar@ubuntu:~/test-git$ git checkout testgitbr1

Switched to branch ‘testgitbr1’

vskumar@ubuntu:~/test-git$ git status

On branch testgitbr1

nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$ cat test1.java

 

class test1{

  public static void main(String args[]){

    System.out.println(“Hello Welcome to DevOps course”);

System.out.println(“Hope you are practicing well Jenkins 2.9”);

System.out.println(“Now, create a java object file through javac compiler”);

System.out.println(“Using Jenkins job creation”);

System.out.println(“Once it is created, you run it by java runtime”);

System.out.println(“Now, compare the console output with your expectation!!”);

  }

}

vskumar@ubuntu:~/test-git$ cat test1.txt

echo ‘Testing line1 for git ..’

echo ‘Testing line2 for git—->’

echo ‘Testing test1.tx for add . function’

echo ‘Checking for changing commit comment’

echo ‘For removal of old comment’

vskumar@ubuntu:~/test-git$

==Note the test1.txt has different content from master =====>

 

Now, let us try to add one README file into master.

I want to create the README file as below:

 

== README file content ===>

vskumar@ubuntu:~/test-git$ pwd

/home/vskumar/test-git

vskumar@ubuntu:~/test-git$ git checkout master

Switched to branch ‘master’

vskumar@ubuntu:~/test-git$ git status

On branch master

nothing to commit, working directory clean

vskumar@ubuntu:~/test-git$

vskumar@ubuntu:~/test-git$ touch README

vskumar@ubuntu:~/test-git$ echo “Testing Master and branches” >> README

vskumar@ubuntu:~/test-git$ cat README

Testing Master and branches

vskumar@ubuntu:~/test-git$ echo “Added this README file into master only” >> README

vskumar@ubuntu:~/test-git$ cat README

Testing Master and branches

Added this README file into master only

vskumar@ubuntu:~/test-git$

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

Let us commit this file into master.

 

=== Status ====>

 

vskumar@ubuntu:~/test-git$ git status

On branch master

Untracked files:

  (use “git add <file>…” to include in what will be committed)

 

README

 

nothing added to commit but untracked files present (use “git add” to track)

vskumar@ubuntu:~/test-git$

=======>

 

Add and  Commit it with message :

 

==== Commit master ===>

 

vskumar@ubuntu:~/test-git$ git add README

vskumar@ubuntu:~/test-git$ git status

On branch master

Changes to be committed:

  (use “git reset HEAD <file>…” to unstage)

 

new file:   README

 

vskumar@ubuntu:~/test-git$

===== Added README ====>

Now, Commit:

 

==== Commit master ===>

vskumar@ubuntu:~/test-git$ git commit -m “Added README file into mater”

[master 1fad32b] Added README file into mater

 1 file changed, 2 insertions(+)

 create mode 100644 README

vskumar@ubuntu:~/test-git$

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

Now, let us view the current hist of master and branch as below with git hist –all:

 

== Current history ===>

 vskumar@ubuntu:~/test-git$ git hist –all

* 1fad32b 2018-03-05 | Added README file into mater (HEAD -> master) [Vsk]

* fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” [Vsk]

| * 26b971b 2018-03-05 | Added all 4 files [2-new and 2 modified] (testgitbr1) [Vsk]

| * 4e7baf8 2018-03-05 | Added a java program [test1.java] to new branch [Vsk]

| * 683ed74 2018-02-24 | Added updated test1.txt [Vsk]

|/  

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

=== You can see on top last two commits of both master and branch =========>

 

21. How to Merge latest objects into single branch ?:

 

Now, we have two different branches. We can consolidate both branches versions and

merge them into a new branch for future developers to use them as one latest project.

Let us go back to the testgitbr1 branch and merge it with master by using the below commands.

git checkout testgitbr1

git merge master

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

vskumar@ubuntu:~/test-git$ git checkout testgitbr1

Switched to branch ‘testgitbr1’

======>

When you use merge command a file opens in vi, just save it as it is.

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

vskumar@ubuntu:~/test-git$ git merge master

Auto-merging test2.txt

Merge made by the ‘recursive’ strategy.

 README    | 2 ++

 test2.txt | 1 –

 2 files changed, 2 insertions(+), 1 deletion(-)

 create mode 100644 README

vskumar@ubuntu:~/test-git$

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

And let us see the current history:

git hist –all

 

===== History =====>

vskumar@ubuntu:~/test-git$ git hist –all

*   6b67f05 2018-03-05 | Merge branch ‘master’ into testgitbr1 (HEAD -> testgitbr1) [Vsk]

|\  

| * 1fad32b 2018-03-05 | Added README file into mater (master) [Vsk]

| * fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” [Vsk]

* | 26b971b 2018-03-05 | Added all 4 files [2-new and 2 modified] [Vsk]

* | 4e7baf8 2018-03-05 | Added a java program [test1.java] to new branch [Vsk]

* | 683ed74 2018-02-24 | Added updated test1.txt [Vsk]

|/  

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

== Let us check the above commit history also =============>

 

From the above exercise, we can conclude any developer can merge his/her current branch into master once they decide to release the code.

 

22. How to reset the earlier created branch from the local repository?:

 

We will see from this exercise, how a developer can reset the earlier branch.

We need to be on the branch now.

we should use ‘git checkout testgitbr1’

 

= Switching to testgitbr1 branch ==>

vskumar@ubuntu:~/test-git$ git checkout testgitbr1

Switched to branch ‘testgitbr1’

vskumar@ubuntu:~/test-git$

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

Now. let us see the current history of the git local repo:

 

==== Git hist====>

 

vskumar@ubuntu:~/test-git$ git hist

*   6b67f05 2018-03-05 | Merge branch ‘master’ into testgitbr1 (HEAD -> testgitbr1) [Vsk]

|\  

| * 1fad32b 2018-03-05 | Added README file into mater (master) [Vsk]

| * fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” [Vsk]

* | 26b971b 2018-03-05 | Added all 4 files [2-new and 2 modified] [Vsk]

* | 4e7baf8 2018-03-05 | Added a java program [test1.java] to new branch [Vsk]

* | 683ed74 2018-02-24 | Added updated test1.txt [Vsk]

|/  

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

== Note, both branches info is available ===>

To remove the testgitbr1 branch we need to reset it.

git reset –hard <hash> —> Here the testgitbr1 branch 1st commit Hash is 4e7baf8.

So our command is; git reset –hard 4e7baf8

 

=== Resetting branch ===>

vskumar@ubuntu:~/test-git$ git reset –hard 4e7baf8

HEAD is now at 4e7baf8 Added a java program [test1.java] to new branch

==== Rsetting is done for branch ===>

Now let us check the hist all:

 

===== Hist all =====>

vskumar@ubuntu:~/test-git$ git hist –all

* 1fad32b 2018-03-05 | Added README file into mater (master) [Vsk]

* fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” [Vsk]

| * 4e7baf8 2018-03-05 | Added a java program [test1.java] to new branch (HEAD -> testgitbr1) [Vsk]

| * 683ed74 2018-02-24 | Added updated test1.txt [Vsk]

|/  

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

== Note;testgitbr1 branch is disappeared ====>

Now let us see the latest history.

So, this way any developer can create and merge a branch and later on it can be destroyed also.

 

23. How to add the current code to github?:

 

create a new repository or use the existing repo on the command line

Create your own github userid and a project in it.

Then you can create repository online. You will see set of commands display on the web page.

Follow them. Or follow as below:

 

Steps for Guthub access:

 

You need to set the project url as below:

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

vskumar@ubuntu:~/test-git$ git remote set-url origin https://github.com/vskumar2017/git-test1.git

vskumar@ubuntu:~/test-git$

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

Please see the below content, I have pushed the code to my account VSKUMAR2017 as below:

 

==== Pushed code to github account ====>

vskumar@ubuntu:~/test-git$ git push origin master –force

Username for ‘https://github.com&#8217;: VSKUMAR2017

Password for ‘https://VSKUMAR2017@github.com&#8217;:

Counting objects: 20, done.

Compressing objects: 100% (16/16), done.

Writing objects: 100% (20/20), 1.85 KiB | 0 bytes/s, done.

Total 20 (delta 2), reused 0 (delta 0)

remote: Resolving deltas: 100% (2/2), done.

To https://github.com/vskumar2017/git-test1.git

 * [new branch]      master -> master

vskumar@ubuntu:~/test-git$

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

 

I have gone throuhg my account and saw the below url:

https://github.com/vskumar2017/git-test1

 

=== As per the below hist it is stored ===>

vskumar@ubuntu:~/test-git$ git hist

* e3fab98 2018-03-05 | first commit (HEAD -> master) [Vsk]

* 1fad32b 2018-03-05 | Added README file into mater [Vsk]

* fdc40ac 2018-02-24 | Revert “Committed test2.txt 3rd change” [Vsk]

* 69282e8 2018-02-24 | Committed test2.txt 3rd change (tag: v1) [Vsk]

* 6bfd9b0 2018-02-24 | Committed test1.txt 3rd change [Vsk]

* 2a7192d 2018-02-24 | Committed:Changes for test1.txt and test2.txt [Vsk]

* 56ccc1e 2018-02-24 | First Commit [Vsk]

vskumar@ubuntu:~/test-git$

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

I have done one more push:

 

==== One more push to github ===>

vskumar@ubuntu:~/test-git$ git checkout master

Switched to branch ‘master’

vskumar@ubuntu:~/test-git$ git add .

vskumar@ubuntu:~/test-git$ git commit -m “A shell sample added “

[master c61b3dd] A shell sample added

 1 file changed, 3 insertions(+)

 create mode 100644 sh1.sh

vskumar@ubuntu:~/test-git$ git push origin master –force

Username for ‘https://github.com&#8217;: VSKUMAR2017

Password for ‘https://VSKUMAR2017@github.com&#8217;:

Counting objects: 3, done.

Compressing objects: 100% (2/2), done.

Writing objects: 100% (3/3), 299 bytes | 0 bytes/s, done.

Total 3 (delta 1), reused 0 (delta 0)

remote: Resolving deltas: 100% (1/1), completed with 1 local object.

To https://github.com/vskumar2017/git-test1.git

   e3fab98..c61b3dd  master -> master

vskumar@ubuntu:~/test-git$

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

 

I have see the below content on my guthub web page of url:https://github.com/vskumar2017/git-test1

===== Message ===>

sh1.sh  A shell sample added just now

======>

 Hope you enjoyed it technically!!

END OF LAB SESSION FOR Git

 

 Vcard-Shanthi Kumar V-v3

 

 

 

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

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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