What is an Ansible Role?
An Ansible role is a way to group multiple tasks, variables, handlers, files, templates, and other resources into a reusable and structured format. Roles provide a method to organize playbooks into separate, independent, and reusable components. This modular approach enhances readability, maintainability, and scalability of Ansible projects.
Creating roles using Ansible Galaxy is a streamlined process. Ansible Galaxy is a command-line tool bundled with Ansible that helps you create, share, and manage roles. Here’s a step-by-step guide to creating roles using Ansible Galaxy:
Step-by-Step Guide to Creating Roles
Create a New Role
Use the ansible-galaxy command to create a new role. Replace role_name with the desired name of your role.
ansible-galaxy init role_nameThis command creates a directory structure for the role:
role_name/
├── README.md
├── defaults
│ └── main.yml
├── files
├── handlers
│ └── main.yml
├── meta
│ └── main.yml
├── tasks
│ └── main.yml
├── templates
├── tests
│ ├── inventory
│ └── test.yml
└── vars
└── main.yml
Key Components of an Ansible Role
- TasksTasks are the main workhorse of a role. They define the steps to be executed. Tasks are stored in
tasks/main.yml.
# roles/role_name/tasks/main.yml
---
- name: Install Apache
ansible.builtin.apt:
name: apache2
state: present
- name: Start Apache service
ansible.builtin.service:
name: apache2
state: started2.Handlers
Handlers are special tasks that are triggered by the notify directive. They are stored in handlers/main.yml.
# roles/role_name/handlers/main.yml
---
- name: Restart Apache
ansible.builtin.service:
name: apache2
state: restarted3.Templates
Templates are files that can be dynamically generated based on variables. They are stored in the templates directory.
Template Example (templates/index.html.j2):
<html>
<head>
<title>Welcome to {{ ansible_hostname }}</title>
</head>
<body>
<h1>Welcome to {{ ansible_hostname }}</h1>
</body>
</html>4.Files
The files directory contains static files that are transferred to the managed hosts.
File Example (files/motd):
Welcome to our server!5.Variables
Variables can be defined at two levels:
- Default Variables (
defaults/main.yml): These are the default values which can be overridden. - Role Variables (
vars/main.yml): These are role-specific variables.
Default Variables Example (defaults/main.yml):
# roles/role_name/defaults/main.yml
---
apache_port: 80Role Variables Example (vars/main.yml):
# roles/role_name/vars/main.yml
---
apache_port: 8080
Meta
The meta/main.yml file defines metadata about the role, such as its dependencies.
Meta Example (meta/main.yml):
# roles/role_name/meta/main.yml
---
dependencies:
- { role: common, some_parameter: 3 }
LibraryThe library directory can contain custom modules that can be used in your role.
TestsThe tests directory is used to store test playbooks and inventory files to test the role.Test Playbook Example (tests/test.yml):
# roles/role_name/tests/test.yml
---
- name: Test Role
hosts: localhost
roles:
- role_name
Using Roles in a Playbook
Once you have defined a role, you can use it in a playbook as follows:
Example Playbook (site.yml):
---
- name: Apply common configuration to all nodes
hosts: all
roles:
- common
- name: Configure web servers
hosts: webservers
roles:
- role_name
Example: Creating and Using a Role
Let’s create a role named webserver to install and configure Apache.
Create the Role Directory Structure:
ansible-galaxy init webserverDefine Tasks:
roles/webserver/tasks/main.yml:
---
- name: Install Apache
ansible.builtin.apt:
name: apache2
state: present
- name: Deploy the index.html file
ansible.builtin.template:
src: index.html.j2
dest: /var/www/html/index.html
notify:
- Restart Apache
- name: Ensure Apache is running
ansible.builtin.service:
name: apache2
state: started
Define Handlers:
roles/webserver/handlers/main.yml:
---
- name: Restart Apache
ansible.builtin.service:
name: apache2
state: restarted
Create a Template:
roles/webserver/templates/index.html.j2:
<html>
<head>
<title>Welcome to {{ ansible_hostname }}</title>
</head>
<body>
<h1>Welcome to {{ ansible_hostname }}</h1>
</body>
</html>
Define Default Variables:
roles/webserver/defaults/main.yml:
---
apache_port: 80
Use the Role in a Playbook:
site.yml:
---
- name: Configure web servers
hosts: webservers
become: yes
roles:
- webserver
Run the Playbook:
ansible-playbook -i inventory site.ymlAnsible roles provide a powerful way to organize and reuse your automation code. By structuring your playbooks into roles, you can manage complex environments more effectively, ensuring consistency and maintainability. Roles encapsulate tasks, handlers, templates, files, variables, and other resources, making it easier to share and reuse configurations across multiple projects and teams. Understanding how to create and use roles is essential for building scalable and maintainable Ansible-based automation solutions.
Example: Creating an nginx Role
Let’s create a role named nginx to install and configure Nginx.
Create the Role:
ansible-galaxy init nginxDefine Tasks:
roles/nginx/tasks/main.yml:
---
- name: Install Nginx
ansible.builtin.apt:
name: nginx
state: present
- name: Start Nginx service
ansible.builtin.service:
name: nginx
state: started
Define Handlers:
roles/nginx/handlers/main.yml:
---
- name: Restart Nginx
ansible.builtin.service:
name: nginx
state: restartedCreate a Template:
roles/nginx/templates/nginx.conf.j2:
server {
listen 80;
server_name {{ server_name }};
location / {
proxy_pass http://{{ proxy_pass }};
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
}
Add Variables:
roles/nginx/defaults/main.yml:
---
server_name: localhost
proxy_pass: 127.0.0.1:8080
Update Meta Information:
roles/nginx/meta/main.yml:
---
galaxy_info:
role_name: nginx
author: your_name
description: Install and configure Nginx
company: your_company
license: MIT
min_ansible_version: 2.9
platforms:
- name: Ubuntu
versions:
- bionic
- focal
dependencies: []
Test the Role:
roles/nginx/tests/test.yml:
---
- name: Test nginx role
hosts: localhost
roles:
- nginx
Run the test playbook:
ansible-playbook roles/nginx/tests/test.yml
Live Practices
root@Jami2:/home/jami# ansible-galaxy init webserver
- Role webserver was created successfullyls 
tree
├── webserver
│  ├── defaults
│  │  └── main.yml
│  ├── files
│  ├── handlers
│  │  └── main.yml
│  ├── meta
│  │  └── main.yml
│  ├── README.md
│  ├── tasks
│  │  └── main.yml
│  ├── templates
│  ├── tests
│  │  ├── inventory
│  │  └── test.yml
│  └── vars
│  └── main.yml
vi webserver/defaults/main.yml
myname: "Rajesh Kumar"
port: 81webserver/files/index.html
Ansible variable
webserver/templates/ports.conf.j2
Listen {{port}}
<IfModule ssl_module>
Listen 443
</IfModule>
<IfModule mod_gnutls.c>
Listen 443
</IfModule>
webserver/tasks/main.yml
- name: Install Apache in Ubuntu
ansible.builtin.apt:
name: apache2
state: latest
- name: Copy index.html
ansible.builtin.copy:
src: /home/jami/index.html
dest: /var/www/html/index.html
- name: Starting a Apache Server
ansible.builtin.service:
name: apache2
state: started
- name: Template for httpd.conf
template:
src: /home/jami/ports.conf.j2
dest: /etc/apache2/ports.conf
notify:
- ReStarting a Apache Servervi webserver/handlers/main.yml
- name: ReStarting a Apache Server
ansible.builtin.service:
name: httpd
state: restartedvi webserver/meta/main.yml
galaxy_info:
author: jami
description: your role description
company: your company (optional)
# If the issue tracker for your role is not on github, uncomment the
# next line and provide a value
# issue_tracker_url: http://example.com/issue/tracker
# Choose a valid license ID from https://spdx.org - some suggested licenses:
# - BSD-3-Clause (default)
# - MIT
# - GPL-2.0-or-later
# - GPL-3.0-only
# - Apache-2.0
# - CC-BY-4.0
license: license (GPL-2.0-or-later, MIT, etc)
min_ansible_version: 2.1
# If this a Container Enabled role, provide the minimum Ansible Container version.
# min_ansible_container_version:
#
# Provide a list of supported platforms, and for each platform a list of versions.
# If you don't wish to enumerate all versions for a particular platform, use 'all'.
# To view available platforms and versions (or releases), visit:
# https://galaxy.ansible.com/api/v1/platforms/
Ansible galaxy – having roles developed by developer
https://galaxy.ansible.com/ui/standalone/roles/geerlingguy/java/install/
ansible-galaxy role install geerlingguy.java
Run roles via below script (currently I have two roles one web and another geerlingguy.java
run below to check role list
ansible-galaxy role listroot@Jami2:/home/jami# ansible-galaxy role list
# /root/.ansible/roles
- geerlingguy.java, 2.5.0
# /etc/ansible/roles
site.yaml
---
- name: Update web servers
hosts: web
roles:
-webserver
-geerlingguy.javaRun ansible playbook
ansible-playbook -i inventory /home/jami/site.yaml -u jami -k -b
As am running on remote server on various server so using inventory in above command
