A Step-By-Step Guide To Write An Ansible Playbook

Step 1: Install Ansible

• Before you can write playbooks, you’ll need to install Ansible on a control machine. This can be your local machine or a dedicated server. Once installed, create a directory to store your playbooks.

Step 2: Set up Inventory

• Define the hosts or servers you want to manage in an inventory file. This can be a simple list of IP addresses or hostnames, or you can organize them into groups based on function, location, etc.

# This is a basic inventory file for Ansible
# It defines the hosts/servers you want to manage

# Hosts can be specified as a hostname, IP address, or name/alias
# You can also specify connection details like ansible_user and ansible_ssh_pass

# For example:
192.168.1.100 ansible_user=admin ansible_ssh_pass=securepass

# Or use hostnames:
webserver01.example.com
webserver02.example.com ansible_user=ubuntu

# Groups allow you to organize hosts for easier management
[webservers]
webserver01.example.com
webserver02.example.com

[dbservers]
db01.example.com
db02.example.com

In this example:

• Whoever is the host is identified as IPs, hostnames or short abbreviations for them.
• This data can be specified per host by setting connection details like ansible_user and ansible_ssh_pass.
• The assignation of hosts to nodes such as [webservers] and [dbservers] is organized into groups.
• There is a parent group e.g. production and consumption which contains the child groups e.g. production and consumption.
• These group variables can be set via ansible_user parameters.
• Cascade appeals court also determined that ensuring confidentiality was quite weightier to the university than in an actual classroom setting.
• The system lets the inventory be pulled (to keep in stock) from many data sources.

The inventory file allows you to specify all the hosts/servers you want to manage with Ansible, along with their grouping and connection details in a simple INI-style format.

• The following screenshot illustrates the defining the IP Addresses of worker nodes.

Step 3: Write Your First Playbook

• A playbook is a YAML file with a .yml extension. It consists of one or more plays, each containing a list of tasks. Here’s the basic structure:

- name: Install and Start Apache
hosts: clients
become: true
tasks:
- name: Update package cache
apt:
update_cache: yes
- name: Install Apache
apt:
name: apache2
state: present
- name: Start Apache service
service:
name: apache2
state: started
enabled: true

In this example:

• hosts parameter defines the cluster of nodes meant for the command execution.
• The word vars is for version which assembles the variables of the play.
• The manner is indexes to be followed.
• which act as a source from which a subsequent activity can be notified/triggered by a previously defined task.

Step 4: Testing And Running

• Before running your playbook on production servers, test it first! Use the –check flag to see changes Ansible will make. When ready, run with:

$ ansible-playbook -i inventory first-playbook.yml

• These are the initial three steps – you’ll understand modules, conditionals, loops, and other Ansible language tools even deeper later. However, this article is aimed at the beginning user so you are encouraged to start writing some playbooks for automaton of common task.

• The following screenshot confirms that we successfully installed and configured the apache web server on our worker nodes through the playbook.

Ansible empowers you to perform all of these tasks by using playbooks which help to write instructions in files. Let’s imagine the playbook to be similar to a recipe book, except from following the steps on a dish, the computers will be getting those one-step-at-a-time instructions. Each playbook is formed from different plays or like than chapters from a book. Every play below it pinpoints the specific functions that are executed by your computers. These functions can be anything from changing users to installing packages, building directories, modifying configuration files, or running scripts. The Ansible itself is pretty interesting as you can create a playbook and then use this playbook on different computers at a time.