Tech Tutorial: Use Roles and Ansible Content Collections #

In this tutorial, we’ll delve into how to manage and utilize Ansible roles and content collections, essential tools for any Red Hat Certified Engineer (RHCE) looking to streamline their automation strategies using Ansible. We’ll specifically focus on how to install and use these roles within playbooks on a system running Red Hat Enterprise Linux (RHEL).

Introduction #

What are Ansible Roles? #

Ansible roles are units of organization in Ansible, which allow you to abstract and encapsulate configurations for reuse and simplification. They make playbook writing easier and more manageable by grouping related tasks, handlers, files, templates, and variables into a standalone, reusable structure.

What are Ansible Content Collections? #

Ansible Collections are a distribution format for Ansible content that can include playbooks, roles, modules, and plugins. Collections allow you to package and distribute all your automation jobs, making it easier to share and reuse Ansible content across projects and teams.

Step-by-Step Guide #

1. Setting Up Your Environment #

Before you begin, ensure you have Ansible installed on your RHEL system. You can install Ansible using the following command with the RHEL package manager:

sudo dnf install ansible

2. Installing Ansible Roles #

Ansible Galaxy is a hub for finding and sharing Ansible content. To install a role from Ansible Galaxy, you can use the ansible-galaxy command. For instance, to install a role called nginx, run:

ansible-galaxy install nginx

This command downloads the nginx role to your default roles directory (typically ~/.ansible/roles).

3. Using Roles in Playbooks #

To utilize an installed role in your playbook, you need to incorporate it within your playbook YAML file. Here is an example of how to include the nginx role in a playbook:

---
- hosts: web_servers
  become: yes
  roles:
    - nginx

This playbook applies the nginx role to hosts in the web_servers group.

4. Installing Ansible Collections #

You can also install collections from Ansible Galaxy. For example, to install a collection named ansible.builtin, you would use:

ansible-galaxy collection install ansible.builtin

5. Using Collections in Playbooks #

After installing a collection, you can use the modules contained within it in your playbooks. Here’s how you might use a module from the ansible.builtin collection:

---
- hosts: all
  tasks:
    - name: Ensure a file is present using the 'file' module from the 'ansible.builtin' collection
      ansible.builtin.file:
        path: /tmp/testfile
        state: touch

This task uses the file module from the ansible.builtin collection to ensure a file exists.

Detailed Code Examples #

Let’s create a more complex playbook that uses both a role and a collection. Suppose we want to deploy a WordPress site on a RHEL server using the nginx role from Galaxy and the mysql module from the community.mysql collection.

First, install the necessary role and collection:

ansible-galaxy install nginx
ansible-galaxy collection install community.mysql

Next, create a playbook like this:

---
- hosts: web_servers
  become: yes
  roles:
    - role: nginx
  tasks:
    - name: Create a database for WordPress
      community.mysql.mysql_db:
        name: wordpress
        state: present

This playbook first applies the nginx role to set up Nginx and then creates a MySQL database named wordpress using a module from the community.mysql collection.

Conclusion #

Using Ansible roles and collections can significantly simplify the management and deployment of configurations across your infrastructure. By encapsulating configurations into roles and organizing various modules and plugins into collections, you can create cleaner, more maintainable Ansible playbooks. Whether you’re automating tasks for a few servers or an entire data center, mastering roles and collections is a crucial skill for any RHCE.

Hopefully, this tutorial provides you with a solid foundation for using Ansible roles and collections effectively in your RHEL environment. Remember, practice is key to mastering these tools, so continue experimenting with different configurations and scenarios to enhance your automation skills.