ANSIBLE

Configuration management systems are designed to streamline the process of controlling large numbers of servers, for administrators and operations teams. They allow you to control many different systems in an automated way from one central location.

While there are many popular configuration management tools 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 offers an architecture that doesn’t require special software to be installed on nodes, using SSH to execute the automation tasks and YAML files to define provisioning details.

Step 1 — Installing Ansible

First, refresh your system’s package index with:

sudo apt update

Following this update, you can install the Ansible software with:

sudo apt install ansible

Press Y when prompted to confirm installation.

Your Ansible control node now has all of the software required to administer your hosts. Next, we’ll go over how to set up an inventory file, so that Ansible can communicate with your managed nodes

Step 2 — Setting Up the Inventory File

The inventory file contains information about the hosts you’ll manage with Ansible

Unlike Chef or Puppet Ansible is a push type of management system.What it means that entire control is lies with master or server.This is where you write your configuration files and also responsible for pushing on to your client as and when required.

Open ansible host file It lies in /etc/ansible/

open gedit /etc/ansible/hosts

In that file it shows so many groups names mentioned between square brackets.

for example

[webservers]

under that it shows the client IP addresses

create a group called ansible_client and mention ssh username and password

all the communication between user and client will through ssh only.ssh will create a secure channel between server and client.

Now save the files after updating client detials

Next step is to write a playbook

Playbook is the technical term used for all the configuration file what we write in ansible. Playbooks are written in yaml format.Now open a file called test.yaml

It start with three dashes

example : ---

It indicates the beginning of file

Now we need to give name of our playbook

Next host system which is same as the group name what we have given in the hosts file.

Now let me show the screen shot of a sample playbook for creating folders and files in our client machine.

---

- hosts: ansible_client

remote_user: labadmin

become: true

tasks:

- name: "create a directory named test"

file:

path: /home/linuxhelp/test

state: directory

- name: "create a file on test directory"

file:

path: /home/linuxhelp/test/file.txt

state: touch

after creating this file now run the following commands

root@G2:/home/labadmin# ansible-playbook test.yml --syntax-check

playbook: test.yml

root@G2:/home/labadmin#

If everything is ok in playbook it will return playbook name

Now we need to push the playbook to our client machine.

command for pusing playbook is

#ansible-playbook test.yml

if some error like following occurs type

#ansible-playbook test.yml -kK

$ ansible-playbook mail.yml -kK 
SSH password: 
BECOME password[defaults to SSH password]:

-k, --ask-pass: ask for connection password
-K, --ask-become-pass: ask for privilege escalation password

Ansible Playbook to run Shell commands

#ansible your_host -m command -a 'command what you need'

example:

ansible ansible_client -m command -a 'hostname'

https://stackoverflow.com/questions/20177996/ansible-playbook-to-run-shell-commands

Manage Users and Groups on Linux using Ansible

Create/Add user and group using Ansible

Playbook, user.yml:

---

- hosts: ansible_client #change to your hosts

become: yes

vars:

# NOTICE!!!:

# DO NOT PUT PLAIN TEXT PASSWORDS HERE!

# use encrypted passwords or put them in Ansible vault

# but this is just a demo

vaulted_password: student

tasks:

- name: Add a group called developer

group:

state: present

- name: Add user exam with a password

user:

password: "{{ vaulted_password | password_hash('sha512') }}"

update_password: on_create

shell: /bin/bash

groups: developer

append: yes

for running the playbook

$ ansible-playbook user.yml -K

Delete/Remove users using Ansible

Playbook, user_delete.yml:

---

- hosts: ansible_client

become: yes

tasks:

- name: Remove exam

user:

state: absent

remove: yes

courtesy: https://computingforgeeks.com/manage-users-and-groups-on-linux-using-ansible/

Executing Shell Programing

Playbook,execute_shell.yml

---

- hosts: ansible_client

remote_user: student

tasks:

- name: Transfer the script

copy: src=test.sh dest=/home/student mode=0777

- name: Execute the script

command: sh /home/student/test.sh

APT Example Ansible

---
 - name: Playbook to install Apache
   hosts: webservers
   become: true
   tasks: 
    - name: Ansible apt install Apache
      apt:
        name: apache2
        state: present

How to remove a Package with Ansible apt

-
 - name: Playbook to install Apache
   hosts: webservers
   become: true
   tasks: 
    - name: Ansible apt install Apache
      apt:
        name: apache2
        state: absent

---

- name: Ansible apt module examples

hosts: ansible_client

become: true

tasks:

- name: Ansible Update Cache and install php

apt:

state: absent

- name: Remove useless packages from the cache

apt:

autoclean: yes

- name: Remove dependencies that are no longer required

apt:

autoremove: yes

How to copy files with Ansible – Local to Remote

All you need is an SSH connection to the remote server. ( with password or SSH key)

- name: Ansible Copy Example Local to Remote
  hosts: remoteserver
  tasks:
    - name: copying file with playbook
      become: true 
      copy:
        src: ~/Downloads/index.html
        dest: /var/www/html
        owner: apache
        group: apache        All you need is an SSH connection to the remote server. ( with password or SSH key)

- name: Ansible Copy Example Local to Remote
  hosts: remoteserver
  tasks:
    - name: copying file with playbook
      become: true 
      copy:
        src: ~/Downloads/index.html
        dest: /var/www/html
        owner: apache
        group: apache        
        mode: 0644
        mode: 0644

Let me explain this in detail

hosts: A target host group should be already defined in the ansible inventory aka hosts file
tasks: all the tasks (plays) would be defined under this
become: this is to tell ansible to execute the corresponding task as a sudo user root unless specified any other user with become_user
copy: module name we are going to use in this task
- src: source file path on the local machine where the playbook or ad-hoc command is invoked ( can set ansible to look for the file in remote server using remote_src as well )
- dest: destination path on the remote server/host where the file should be copied to
- owner: Owner of the file at the destination server once copied
- group: Group of the file at the destination server once copied
- mode: setting the permission of the file after copying. 0644 would be set as permission on the filerw- r-- r--

this can be executed in a single line as an ad hoc command as well.

ansible remoteserver1 -m copy -a "src=~/Downloads/index.html dest=/var/www/html owner=apache group=apache mode=0644"

Sending Notification to All clients

Example:

ansible ansible_client -m command -a 'notify-send "My name is bash and I rock da house"'

Errors facing:

fatal: [192.168.15.81]: FAILED! => {"msg": "Using a SSH password instead of a key is not possible because Host Key checking is enabled and sshpass does not support this. Please add this host's fingerprint to your known_hosts file to manage this host."}

Answer: If you run firsttime a playbook to client you may not push the conf to client for that first time you need to login manual by using ssh command and then run.

2. Using a SSH password instead of a key is not possible because Host Key checking is enabled and sshpass does not support this. Please add this host's fingerprint to your known_hosts file to manage this host.Create a file ansible/ansible.cfg in your project directory (i.e. ansible.cfg in the provisioning_path on the target) with the following contents:

[defaults]
host_key_checking = false

https://stackoverflow.com/questions/42462435/ansible-provisioning-error-using-a-ssh-password-instead-of-a-key-is-not-possibl

`ANSIBLE NEW VERSION UPDATE`

sudo -H pip install --upgrade ansible

courtesty : https://stackoverflow.com/questions/34903026/update-ansible-1-9-4-to-ansible-2-0

courtesy:https://www.youtube.com/watch?v=EcnqJbxBcM0

https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-ansible-on-ubuntu-20-04#introduction

https://www.middlewareinventory.com/blog/ansible-playbook-example/

https://www.softwaretestinghelp.com/ansible-playbooks-ansible-vaults/

ANSIBLE PLAYBOOKS

INSTALLING SOFTWARE EXAMPLE

---

- name: Install Dia Diagramming Application

hosts: rs

become: yes

tasks:

- name: Install Dia

apt:

name: dia

state: present

- name: Verify Dia installation

command: which dia

register: dia_installed

changed_when: false

failed_when: dia_installed.rc != 0

- name: Ensure Dia is installed

debug:

msg: "Dia installed at {{ dia_installed.stdout }}"

when: dia_installed.rc == 0

SHUTDOWN

---

- name: Shutdown PC

hosts: pjl

become: yes

tasks:

- name: Shutdown the machine

command: /sbin/shutdown now

async: 1

poll: 0

- name: Wait for machine to shut down

pause:

minutes: 1

Search This Blog

ANSIBLE

ANSIBLE

Step 1 — Installing Ansible

Step 2 — Setting Up the Inventory File

Ansible Playbook to run Shell commands

Manage Users and Groups on Linux using Ansible

Create/Add user and group using Ansible

Delete/Remove users using Ansible

Executing Shell Programing

APT Example Ansible

How to remove a Package with Ansible apt

How to copy files with Ansible – Local to Remote

Sending Notification to All clients

`ANSIBLE NEW VERSION UPDATE`

ANSIBLE PLAYBOOKS

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