Molecule Testing for Ansible

1. Introduction

Molecule is a testing framework for Ansible roles. It provides a way to test your roles in isolation using various drivers (like Docker, Vagrant, etc.) and testing frameworks (like Testinfra, Goss, etc.). This lesson will guide you through the process of using Molecule to ensure your Ansible roles work as intended.

2. What is Molecule?

Molecule is designed to aid the development and testing of Ansible roles. It allows you to create testing scenarios, manage instances, and validate the configuration of your systems. Key features include:

• Supports multiple cloud providers and virtualization technologies.
• Integrates with various testing frameworks.
• Allows for the creation of reusable scenarios.

3. Installation

Before using Molecule, ensure you have Python and Ansible installed. You can install Molecule using pip:

pip install molecule

Depending on the driver you want to use (e.g., Docker), you may need to install additional dependencies. For Docker, install the following:

pip install molecule[docker]

4. Creating a Molecule Scenario

To create a new Molecule scenario, navigate to your Ansible role directory and run:

molecule init scenario --driver-name docker

This command creates a new directory structure for your scenario, including configuration files and a default test suite.

5. Testing Your Role

To test your role, use the following command:

molecule test

This command will run through the following lifecycle:

            graph TD;
                A[Start] --> B[Create Instance]
                B --> C[Converge]
                C --> D[Verify]
                D --> E[Destroy Instance]
                E --> F[Finish]
        

6. Best Practices

Follow these best practices to make the most of Molecule testing:

• Use version control for your Molecule scenarios.
• Keep your tests isolated and focused on specific functionality.
• Regularly update your Molecule and Ansible versions to leverage improvements.

7. FAQ