Step by Step procedure to install and Configure ANSIBLE on Ubuntu

Step by step procedure to install and configure ansible on ubuntu

Before installing ANSIBLE, let us understand,

What is ANSIBLE ?

1.Ansible Introduction :

Ansible is an IT automation tool. It can configure systems, deploy software, and orchestrate more advanced IT tasks such as continuous deployments or zero
downtime rolling updates.
Ansible’s goals are foremost those of simplicity and maximum ease of use. It also has a strong focus on security and reliability, featuring a minimum of moving parts, usage of OpenSSH for transport (with an accelerated socket mode and pull modes as alternatives),
and a language that is designed around auditability by humans – even those not familiar with the program.

While there are many popular configuration management systems available for Linux systems, such as Chef and Puppet, these are often more complex than many people want or need.Ansible is a great alternative to these options because it has a much smaller overhead to get started.

for more information visit, Ansible docs.
http://docs.ansible.com/

Assumptions
● You have a ubuntu 12.04 and you are logged-in as root.

2.How Does Ansible Work :
Ansible works by configuring client machines from an computer with Ansible components
installed and configured.
It communicates over normal SSH channels in order to retrieve information from remote
machines, issue commands, and copy files. Because of this, an Ansible system does not require any additional software to be installed on the client computers.
This is one way that Ansible simplifies the administration of servers.
Configuration files are mainly written in the YAML data  format due to its
expressive nature and its similarity to popular markup languages.Ansible can interact with clients through either command line tools or through its configuration scripts called Playbooks.

3. Install Ansible on an Ubuntu 12.04 :
To begin exploring Ansible , we need to install the Ansible package on at least one machine. I have used ubuntu 12.04

git clone git@github.com:ansible/ansible.git
cd ansible
source ./hacking/env-setup
sudo pip install paramiko PyYAML jinja2 --upgrade

We now have all of the software required to administer our servers through Ansible.
Set Up SSH Keys , Ansible primarily communicates with client computers through SSH.While it certainly has the ability to handle password-based SSH authentication, SSH keys help keep things simple.

4. Creating a SSH Pair :
@Server:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa):
Created directory ‘/home/a/.ssh’.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A
Now use ssh to create a directory ~/.ssh as user b on Client. (The directory may already exist,
which is fine):
@Server:~> ssh root@123.123.123.123 mkdir -p .ssh
root@Client’s password:
Finally append a’s new public key to root@123.123.123.123:.ssh/authorized_keys and enter
client’s password one last time:
root@Server:~> cat .ssh/id_rsa.pub | ssh root@123.123.123.123 ‘cat >> .ssh/authorized_keys’
root@Client’s password:
From now on you can log into Client as root from A as a without password:
@Server:~> ssh root@123.123.123.123

5. Configuring Ansible Host:
Ansible keeps record of all of the servers that it know through a “hosts” file. We need to configure this file first before we can begin to communicate with our other computers.
Open the file and add,

vim /etc/ansible/hosts
[hosts]
devops ansible_ssh_host=123.123.123.123

Where hosts is list of nodes
devops = host name of one of the client.
123.123.123.123 is hosts ip.
To do this, we will create a directory in the Ansible configuration structure called group_vars.
Within this folder, we can create YAML-formatted files for each group we want to configure:

sudo mkdir /etc/ansible/group_vars
sudo nano /etc/ansible/group_vars/hosts

We can put our configuration in here. YAML files start with “—“, so make sure you don’t forget that part.

ansible_ssh_user: root
Save and close this file when you are finished.

6. Ansible test Examples:

Using Simple Ansible Commands
Now that we have our hosts set up and enough configuration details to allow us to
successfully connect to our hosts, we can try out our very first command.
Ping all of the servers you configured by typing:
root@server:/etc/ansible# ansible -m ping hosts
devops | success >> {
“changed”: false,
“ping”: “pong”
}
This is a basic test to make sure that Ansible has a connection to all of its hosts.

ansible -m shell -a ‘ifconfig’ devops

devops | success | rc=0 >>
eth0 Link encap:Ethernet HWaddr 00:0c:29:a2:42:c4
inet addr:123.123.123.123 Bcast:10.27.111.255 Mask:255.255.255.0

ansible -m shell -a ‘free -m’ devops
devops | success | rc=0 >>
total used free shared buffers cached
Mem: 487 440 47 0 108 173
-/+ buffers/cache: 158 329
Swap: 507 66 441

Lets install sendmail on client from Ansible server, to do that create playbook.yml file in
/etc/ansible 100 Jul 5 02:48 playbook.yml

root@server:/etc/ansible# cat playbook.yml

– hosts: devops
tasks:
– name: 1. install sendmail
apt: name=sendmail state=present

Now execute below command to install on remote server.
ansible-playbook –inventory-file=hosts playbook.yml –sudo –verbose
Below is the result,

ansible 1

Before executing above command, sendmail was not installed. ansible 2

Later after execution, sendmail installed on the remote host.

Advantages of Automation,

,Automation-Advantages

Hence we have Installed and Configured ANSIBLE, Enjoy !!!

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