Introduction
Molecule, the testing framework for Ansible roles and playbooks, introduces powerful functionality through its concept of scenarios. Think of a scenario as a test suite for roles or playbooks within an Ansible collection. This article delves into Molecule scenarios, their layout, and how to harness their capabilities for efficient testing and development.
Ansible Collection
Adding Molecule to your Ansible collection is a straightforward process that enhances your development and testing workflow. Start by creating a new directory within your collection named "extensions." Navigate to this newly created directory using the command line and then initialize a new default Molecule scenario with the following:
``bash
cd <path to your collection>/extensions/
molecule init scenario
`
This step sets the foundation for incorporating Molecule into your collection, allowing you to seamlessly integrate testing and development practices. The newly created scenario within the "extensions" directory becomes a pivotal component in orchestrating Molecule's testing lifecycle for your Ansible roles and playbooks.
Understanding the Scenario Layout
The scenario layout is crucial for organizing Molecule's testing components. Within the molecule/default folder, several key files play distinct roles:
- create.yml
: This playbook file creates instances and stores data in the instance-config.
- destroy.yml
: Contains Ansible code for destroying instances and removing them from the instance-config.
- molecule.yml
: The central configuration entry point for Molecule per scenario, allowing configuration of each tool for testing roles.
- converge.yml
: A playbook file invoking your role. Molecule uses this file withansible-playbookto run against an instance created by the driver.
Inspecting the molecule.yml Configuration
The molecule.yml` file is pivotal for configuring Molecule. It's a YAML file with keys representing high-level components:
1. Dependency Manager: Molecule defaults to using the Galaxy development guide to resolve role dependencies.
2. Platforms Definitions: Specifies instances to create, their names, and group assignments. Useful for testing roles against multiple distributions.
3. Provisioner: Molecule's Ansible provisioner manages instance lifecycles based on this configuration.
4. Scenario Definition: Controls the sequence order of scenarios.
5. Verifier Framework: Defaults to using Ansible, pr