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Installation and Configuration of Ansible

Srikanth Kumar Sridhara's avatarPosted by

Introduction to Ansible :-

Ansible is an agent-less IT automation tool developed in 2012 by Michael DeHaan, a former Red Hat associate. The Ansible design goals are : minimal, consistent, secure, highly reliable, and easy to learn.Ansible is Written on Python language.It also available as Open Source.

Why to use Ansible as automation tool ?

  • There are many other IT automation tools available, including more mature ones like Puppet and Chef, so why would we choose Ansible? The main reason is simplicity.
  • Ansible is using YAML syntax. It’s simple configuration language.
    Puppet and Chef are using Ruby Syntax. which is more difficult to learn.
  • Ansible is an agentless tool.Instead of install an agent on every target machine, Ansible just requires that target systems have Python (on Linux servers) or PowerShell (on Windows servers) and SSH.But puppet and chef have to install agent on each target machines.

High Level Steps : –

  • Install Python software
  • Install PIP to install Cx_Oracle package to perform SQL commands
  • Install ansible rpm
  • Configure SSH to connect remote hosts
  • Run the ansible command to access remote hosts.

Step 1:- Check the Current version of Python in OEL 7:-

[root@ansible ~]$ python -V
Python 2.7.5

Note:- Minimum version of python 2.7.6 is needed to install ansible.

Step 2:- Download the Python 2.7.6 package

[root@ansible ansible]# wget -c https://www.python.org/ftp/python/2.7.6/Python-2.7.6.tgz --no-check-certificate
--2018-07-19 02:16:25-- https://www.python.org/ftp/python/2.7.6/Python-2.7.6.tgz
Resolving www.python.org (www.python.org)... 151.101.184.223, 2a04:4e42:2c::223
Connecting to www.python.org (www.python.org)|151.101.184.223|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 14725931 (14M) [application/octet-stream]
Saving to: ‘Python-2.7.6.tgz’

100%[============================================================================================================>] 14,725,931 240KB/s in 65s

2018-07-19 02:17:32 (221 KB/s) - ‘Python-2.7.6.tgz’ saved [14725931/14725931]

Step 3:- Unzip the downloaded python package

[root@ansible ~]$ tar -xvzf Python-2.7.6.tgz 

[root@ansible ~]$ cd Python-2.7.6

[ansible@ansible Python-2.7.6]$ ls -lrt
total 956
-rw-r--r--. 1 ansible ansible 12749 Nov 10 2013 LICENSE
drwxr-xr-x. 2 ansible ansible 4096 Nov 10 2013 Include
drwxr-xr-x. 2 ansible ansible 20 Nov 10 2013 Grammar
drwxr-xr-x. 22 ansible ansible 4096 Nov 10 2013 Demo
drwxr-xr-x. 46 ansible ansible 8192 Nov 10 2013 Lib
drwxr-xr-x. 22 ansible ansible 4096 Nov 10 2013 Tools
-rw-r--r--. 1 ansible ansible 97308 Nov 10 2013 setup.py
drwxr-xr-x. 5 ansible ansible 4096 Nov 10 2013 RISCOS
-rw-r--r--. 1 ansible ansible 53972 Nov 10 2013 README
drwxr-xr-x. 2 ansible ansible 4096 Nov 10 2013 Python
-rw-r--r--. 1 ansible ansible 34829 Nov 10 2013 pyconfig.h.in
drwxr-xr-x. 2 ansible ansible 4096 Nov 10 2013 PCbuild
drwxr-xr-x. 10 ansible ansible 4096 Nov 10 2013 PC
drwxr-xr-x. 2 ansible ansible 4096 Nov 10 2013 Parser
drwxr-xr-x. 3 ansible ansible 4096 Nov 10 2013 Objects
drwxr-xr-x. 9 ansible ansible 4096 Nov 10 2013 Modules
drwxr-xr-x. 5 ansible ansible 4096 Nov 10 2013 Misc
-rw-r--r--. 1 ansible ansible 44172 Nov 10 2013 Makefile.pre.in
drwxr-xr-x. 11 ansible ansible 4096 Nov 10 2013 Mac
-rwxr-xr-x. 1 ansible ansible 7122 Nov 10 2013 install-sh
-rw-r--r--. 1 ansible ansible 133573 Nov 10 2013 configure.ac
-rwxr-xr-x. 1 ansible ansible 426595 Nov 10 2013 configure
-rwxr-xr-x. 1 ansible ansible 35639 Nov 10 2013 config.sub
-rwxr-xr-x. 1 ansible ansible 44851 Nov 10 2013 config.guess
drwxr-xr-x. 16 ansible ansible 4096 Nov 10 2013 Doc

Step 4:- Configuring python 2.7.6 software

Create the below directory ‘/home/ansible/python’ and configure,install the software.

[ansible@ansible Python-2.7.6]# ./configure --prefix=/home/ansible/python

[ansible@ansible Python-2.7.6]# make

[ansible@ansible Python-2.7.6]# make install

After installation,the following files are created under ‘/home/ansible/python’

[ansible@ansible Python-2.7.6]# ls -lrt /home/ansible/python
total 4
drwxr-xr-x. 3 ansible ansible 22 Jul 19 21:10 include
drwxr-xr-x. 4 ansible ansible 59 Jul 19 21:10 lib
drwxr-xr-x. 3 ansible ansible 16 Jul 19 21:10 share
drwxr-xr-x. 2 ansible ansible 4096 Jul 19 21:10 bin

Now,check the new python version 2.7.6

[root@ansible ~]$ cd python/bin/
[root@ansible bin]$ python -V
Python 2.7.6

[root@ansible bin]# which python
/home/ansible/bin/python

Step 5:- Download PIP package

[root@ansible ~]$ curl "https://bootstrap.pypa.io/get-pip.py" -o "get-pip.py"
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
100 1603k 100 1603k 0 0 164k 0 0:00:09 0:00:09 --:--:-- 222k

[root@ansible ansible]# python get-pip.py
Collecting pip
Downloading https://files.pythonhosted.org/packages/0f/74/ecd13431bcc456ed390b44c8a6e917c1820365cbebcb6a8974d1cd045ab4/pip-10.0.1-py2.py3-none-any.whl (1.3MB)
100% |████████████████████████████████| 1.3MB 709kB/s
Collecting wheel
Downloading https://files.pythonhosted.org/packages/81/30/e935244ca6165187ae8be876b6316ae201b71485538ffac1d718843025a9/wheel-0.31.1-py2.py3-none-any.whl (41kB)
100% |████████████████████████████████| 51kB 1.2MB/s
Installing collected packages: pip, wheel
Successfully installed pip-10.0.1 wheel-0.31.1

[root@ansible ansible]# python -m pip install cx_Oracle --upgrade
Collecting cx_Oracle
Downloading https://files.pythonhosted.org/packages/3b/09/6b10675a6db7c7da1b8d23225f0a95b2a45248c56a1e8f711d59809278d3/cx_Oracle-6.4.1-cp27-cp27mu-manylinux1_x86_64.whl (590kB)
100% |████████████████████████████████| 593kB 1.2MB/s
Installing collected packages: cx-Oracle
Successfully installed cx-Oracle-6.4.1

Check the PIP version :-

[root@ansible ansible]# pip -V
pip 10.0.1 from /usr/lib/python2.7/site-packages/pip (python 2.7)

We need the Cx_Oracle Package for executing SQL’s , performing any task inside SQL prompt.

[root@ansible ansible]# python
Python 2.7.5 (default, Sep 5 2016, 02:30:38)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-9)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cx_Oracle
>>> exit()

Installation of Ansible software :-

Step 6:-To get Ansible for Linux, first ensure that the RHEL7 EPEL repository is installed:

[root@ansible ~]# rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
Retrieving https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
warning: /var/tmp/rpm-tmp.dwLJVq: Header V3 RSA/SHA256 Signature, key ID 352c64e5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:epel-release-7-11 ################################# [100%]

Step 7:- Once the repository is installed, install Ansible with yum:

[root@ansible ~]# yum install ansible

Step 8:- Check the ansible version and configuration file path

[root@ansible ~]$ ansible --version
ansible 2.6.1
config file = /etc/ansible/ansible.cfg
configured module search path = [u'/home/ansible/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python2.7/site-packages/ansible
executable location = /bin/ansible
python version = 2.7.5 (default, Sep 5 2016, 02:30:38) [GCC 4.8.5 20150623 (Red Hat 4.8.5-9)]

Step 9:- Configuring ansible hosts and create inventory file.

The ‘database–servers‘ in the brackets indicates as group names to list number of remote hosts.

[root@ansible ~]# vi /etc/ansible/hosts

Added the below remote host entry to the /etc/ansible/hosts file

[database-servers]
demo.localdomain.com

Step 10:- List the remote hosts which are able to use ansible commands

[root@ansible ~]$ ansible --list-host all
hosts (1):
192.168.86.141

[ansible@ansible ~]$ ansible --list-host database-servers
hosts (1):
192.168.86.141

SSH Key creation :-

Step 11:- Create the SSH user equivalence in the ansible server.

[ansible@ansible ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/ansible/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/ansible/.ssh/id_rsa.
Your public key has been saved in /home/ansible/.ssh/id_rsa.pub.
The key fingerprint is:
3f:58:1b:ca:6c:2a:66:0d:63:ea:c3:18:a3:45:45:43 ansible@ansible.localdomain.com
The key's randomart image is:
+--[ RSA 2048]----+
| oE |
| .. |
| . |
| . |
| . S o |
|o . + o = o |
|.* o + * + |
|o + + .o . |
| ..+ .. |
+-----------------+

[ansible@ansible ~]$ cd .ssh/
[ansible@ansible .ssh]$ ls -lrt
total 8
-rw-r--r--. 1 ansible ansible 413 Jul 20 19:40 id_rsa.pub
-rw-------. 1 ansible ansible 1675 Jul 20 19:40 id_rsa

Step 12:- Copy the SSH key to the remote servers

[root@ansible .ssh]# ssh-copy-id root@demo.localdomain.com
/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@demo.localdomain.com's password:

Number of key(s) added: 1

Now try logging into the machine, with: "ssh 'root@demo.localdomain.com'"
and check to make sure that only the key(s) you wanted were added.

Step 13:- Now,we are able to ping the remote hosts,

[root@ansible .ssh]# ansible all -m ping
demo.localdomain.com | SUCCESS => {
"changed": false,
"ping": "pong"

Step 14 :- To check the partitions on all remote hosts

[root@ansible ~]# ansible -m command -a "df -h" database-servers
demo.localdomain.com | SUCCESS | rc=0 >>
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_rac1-lv_root
36G 19G 16G 55% /
tmpfs 2.0G 276K 2.0G 1% /dev/shm
/dev/sda1 485M 82M 378M 18% /boot

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