Ansible Development: Write Custom Modules, Plugins & Collections
By Luca Berton · Published 2024-01-01 · Category: installation
Guide to Ansible development. Create custom modules, action plugins, filter plugins, and collections. Set up dev environments and testing with examples.
Ansible Development: A Comprehensive Guide
Ansible is an open-source automation tool developed by Red Hat that enables IT professionals to automate tasks such as configuration management, application deployment, and task automation. This article delves into the essential aspects of Ansible development, covering its architecture, core concepts, and practical applications.
Understanding Ansible Architecture
Ansible's architecture comprises the following key components: Ansible Engine: This is the core component that executes the automation tasks defined in Ansible playbooks. Ansible Playbooks: Written in YAML, playbooks describe the desired state of the system and define the tasks to be executed. Ansible Inventory: This is a file that lists the hosts and groups of hosts that Ansible will manage. Modules: These are the units of work that Ansible executes. They can be anything from installing software to managing services. Plugins: These extend Ansible’s core functionalities, including action plugins, cache plugins, and callback plugins.
Ansible operates on a push model, where tasks are executed from a central control node to the managed nodes over SSH or WinRM, eliminating the need for agent software on the managed nodes.
Getting Started with Ansible
Ansible is favored for its simplicity and ease of use. Here’s how you can get started with Ansible: Installation: Ansible can be installed on any Unix-like system, including macOS and Linux. It can also be run on Windows under the Windows Subsystem for Linux (WSL). Setting Up an Inventory: The inventory file defines the hosts and groups of hosts to manage. Writing Your First Playbook: Ansible playbooks are written in YAML. Here’s a simple example that installs Nginx on web servers. Executing Playbooks: Run your playbook with the ansible-playbook command.
Core Ansible Concepts Roles: Roles provide a way to organize playbooks and related files to be easily shared and reused. Variables: Variables allow you to store values that can be reused and overridden as needed. Handlers: Handlers are tasks that are run when notified by other tasks. Templates: Templates in Ansible are used to fill configuration files with variables.
Advanced Ansible Usage Ansible Tower: Ansible Tower is a web-based solution that makes Ansible even more powerful by providing role-based access control, job scheduling, and graphical inventory management. Dynamic Inventory: This is used to manage and interact with hosts that are not statically defined in the inventory file, such as cloud environments. Custom Modules and Plugins: While Ansible comes with many built-in modules, custom modules can be written to extend its functionality using any programming language, although Python is most common.
Integrating Ansible with Kubernetes
Ansible can manage Kubernetes clusters, automating tasks such as cluster provisioning, application deployment, and configuration management. The k8s module allows you to interact with Kubernetes resources directly from Ansible playbooks.
Conclusion
Ansible is a powerful tool for automating a wide range of IT tasks. Its simple, agentless architecture and human-readable automation language make it accessible to both beginners and seasoned professionals. Whether you are managing traditional infrastructure, containerized environments, or cloud services, Ansible provides the tools you need to automate and orchestrate your IT operations efficiently.
For more detailed guidance and advanced topics, refer to the comprehensive resources available in Red Hat’s documentation and the community-contributed materials on platforms like GitHub and Ansible Galaxy.
Custom Module (Basic)
Module with API Calls
Custom Filter Plugin
Custom Lookup Plugin
Collection Structure
Testing Modules
Development Environment
FAQ
Where do I put custom modules?
In library/ next to your playbook, or in a roles/
Do modules need to be Python?
Modules can be any language — Ansible sends JSON input and expects JSON output. Python is most common due to AnsibleModule helper.
How do I publish a collection?
Custom Module (Python)
Custom Filter Plugin
Custom Lookup Plugin
Development Environment
Collection Development
Testing Modules
FAQ
Where to put custom modules?
In library/ next to your playbook, in a role's library/, or in a collection's plugins/modules/.
How to debug modules?
Set ANSIBLE_KEEP_REMOTE_FILES=1 — Ansible leaves the module on the remote host. SSH in and run with Python directly.
Module vs Plugin?
Modules run on remote hosts (tasks). Plugins run on the controller (filters, lookups, callbacks, connection types).
Related Articles • Ansible Galaxy Guide • Ansible Template Guide • Ansible Handlers Guide • Ansible for Windows Guide • Ansible Become Guide
Category: installation