Unleashing the Power of Plugins: Building Custom Features in Ansible


The Importance of Ansible in Automation

Ansible is a powerful, open-source automation tool designed for managing and configuring multiple systems. It allows users to automate repetitive tasks, manage complex environments, and streamline their IT infrastructure.

Ansible is known for its simplicity and ease of use, making it an ideal solution for beginners or advanced users alike. Ansible’s popularity has skyrocketed in recent years due to its exceptional capabilities.

It enables IT professionals to reduce manual workload, increase efficiency, and reduce errors significantly. With Ansible, sysadmins can automate repetitive tasks like software installations, system updates, backups, and much more.

The benefits mentioned above make Ansible the go-to automation tool for businesses in various industries worldwide. Its growing popularity also leads to high demand and an increasing number of developers expanding its functionality.

Overview of Plugins and Their Role in Ansible Customization

Plugins are an essential component in Ansible that allow users to extend its functionality beyond what comes out-of-the-box. They are pieces of code that modify or add new features to the core functions of the tool.

Plugins come with different types that include modules (task-oriented), inventory (source data), callbacks (triggered by events), filters (modify data), dynamic inventory (generate inventory on-the-fly). In addition to these pre-built plugins types that come with the installation package one can create custom plugins as well.

Plugins play a critical role in facilitating customization with Ansible because they allow users to tailor the tool according to their specific needs without tinkering with core source code. In this article we will delve deeper into how plugins work within the context of Ansible while exploring how they can be leveraged effectively for building customized features with ease.

Understanding Plugins

Plugins are an essential part of the Ansible ecosystem, providing a way to extend its functionalities beyond what is already built-in. A plugin can be defined as a self-contained piece of code that adds a specific feature or functionality to Ansible. There are five types of plugins in Ansible:

1. Modules: These plugins define the basic building blocks of any Ansible playbook. Modules provide actions such as copying files, creating users, and installing packages.

2. Inventory: These plugins allow Ansible to obtain inventory data, including hostnames and IP addresses. 3. Connection: These plugins define how Ansible connects to remote machines for execution.

4. Lookup: These plugins provide a way of retrieving information from sources outside your playbook. 5. Callbacks: These plugins enable you to handle or respond to events that occur during playbook execution on remote machines.

Importance of Plugins in Extending Ansible Functionality

Ansible is an open-source automation tool, and its developers have designed it with flexibility and extensibility in mind. Plugins play a crucial role in extending the functionality of Ansible by providing additional actions and features that can be used by developers and sysadmins alike. With the help of custom modules, you can automate complex tasks that are not possible with the built-in modules available out-of-the-box with Ansible.

By writing custom inventory or connection plugins, you can configure connections to various types of systems using different protocols or access methods depending on your infrastructure’s unique requirements. Custom callbacks make it possible for you to perform specific actions when events occur during playbook execution remotely.

Examples Of Popular Plugins Used In Ansible

There are several popular third-party plugin libraries available for use with Ansible, each offering unique features that enhance the overall functionality and experience while working with it. The most widely used external plugin library is “ansible-galaxy,” which contains hundreds of custom plugins, modules, and playbooks contributed by Ansible users worldwide.

Other popular Ansible plugins include the “docker-py” plugin for interacting with Docker containers, “openshift-ansible” for deploying OpenShift clusters, and the “ec2.py” inventory plugin for AWS cloud environments. Custom callback plugins are also widely used in various organizations to send notifications to IT teams via chat or email when specific events occur during playbook execution.

Understanding the different types of plugins in Ansible is essential for harnessing their power to extend its functionality and automate almost anything. By leveraging pre-built third-party plugins or creating your own from scratch, you can customize and adapt Ansible to meet your unique infrastructure’s needs.

Building Custom Features with Plugins

Identifying the Need for a Custom Feature

Before building a custom feature using plugins, it’s important to identify whether it is necessary. This involves determining what specific functionality is required that isn’t already available in Ansible’s standard modules.

Identifying the need for a custom feature involves analyzing the infrastructure being managed and identifying any gaps or limitations in Ansible’s current capabilities. For instance, suppose your organization needs to migrate data from one platform to another.

You can use Ansible’s existing modules to automate the process, but you may need to enhance them with additional features such as error handling or progress tracking. In this example, you would identify the need for a custom plugin that would provide these additional functionalities.

Choosing the Appropriate Plugin Type

Once you’ve identified the need for a custom feature, you must determine which type of plugin should be used. There are several types of plugins available in Ansible: action, filter, inventory, lookup and module plugins.

Each type serves a different purpose and has its own set of requirements. Action plugins are used to define new actions that can be executed on target hosts as part of playbooks.

Filter plugins are used to manipulate data within playbooks by performing operations on variables or other values. Lookup plugins retrieve information from external sources such as files or APIs and manipulate them based on defined rules.

Inventory plugins allow dynamic inventory sources that can update an inventory during runtime based on variables like IP addresses or hostnames. Module plugins provide functionality similar to core modules but customized for specific use-cases.

Writing the Plugin Code

Once you have determined which type of plugin will be suitable for your requirements, it’s time to start writing code for it. Writing code requires knowledge of programming languages such as Python and YAML for configuration files.

The actual implementation varies depending on the type of plugin chosen. For instance, if you’re creating an action plugin, you need to define the behavior that will be executed on target hosts.

Similarly, a filter plugin requires defining how data is manipulated in playbooks. Writing code involves following best practices such as well-defined naming conventions, commenting and documenting code for better understanding.

Testing and Validating the Plugin

After writing code, it’s essential to test and validate your custom plugin. Testing helps ensure that functionality works as expected without breaking other parts of your infrastructure or automation workflows. You can use frameworks like Molecule to test plugins in a Docker container with multiple operating systems.

Validating is another important step that involves verifying if coding guidelines were followed correctly. It also checks if the custom feature has met the specified requirements and doesn’t conflict with existing modules or plugins.

Real-World Examples of Custom Features Built Using Plugins

Custom features built using plugins have widespread use-cases from automating compliance tasks to automating application deployments. For instance, “Jenkins” is a popular automation tool used in DevOps workflows.

A custom inventory plugin can populate host information during runtime from Jenkins API calls instead of static inventory files. Another example is “HashiCorp Vault”, which provides API access for secrets management across different platforms.

Instead of manually configuring access tokens between Ansible and Vault for every playbook run, a custom lookup plugin can retrieve secrets directly from HashiCorp Vault during playbook execution. Building custom features with plugins in Ansible enhances automation workflows by providing new functionalities specific to an organization’s needs while maintaining compatibility with existing modules and plays an essential role in successful infrastructure management.

Exploring Advanced Plugin Development Techniques

Using Dynamic Inventory Sources with Plugins

Dynamic inventory sources can be used to configure and manage hosts automatically, making it easier to manage large infrastructures. Plugins can be used to create these dynamic inventory sources, allowing for more efficient and effective management of systems. One way to use dynamic inventory sources with plugins is by creating a custom cache plugin that stores information about the hosts in a specific format.

This plugin can then be used as an inventory source for Ansible, allowing users to easily manage hosts across different systems. Additionally, plugins like the OpenStack Dynamic Inventory plugin provide easy integration with cloud-based systems, making it simple for users to automate tasks on cloud infrastructure.

Creating Complex Data Structures with Filters and Callbacks

Filters and callbacks are powerful tools that can be used in conjunction with plugins to create complex data structures. Filters are functions that are applied during playbook execution and modify the data passed through them.

Callbacks are functions that are executed after each task has been completed and return information about the state of the system. A common example of using filters and callbacks is when creating custom modules for specific platforms or systems.

These modules can use filters to transform data into a format that is usable by Ansible, allowing for more efficient automation of tasks. Callbacks can also provide useful information about the state of the system after a task has been completed, helping users monitor their infrastructure more effectively.

Building Custom Modules to Work with Specific Systems or Platforms

Building custom modules allows users to extend Ansible’s functionality beyond what is provided out-of-the-box. Custom modules can be created using Python, making it possible for developers to integrate complex logic into their automation workflows. Custom modules can be created for specific platforms or systems by leveraging existing APIs or writing code from scratch.

For example, a custom module could be created to manage Docker containers using the Docker API, allowing for more efficient deployment and management of containerized applications. Another example is building a custom module that leverages the AWS API to manage EC2 instances or S3 buckets.

Examples Showcasing Advanced Plugin Development Techniques

To showcase how advanced plugin development techniques can be used in real-world scenarios, here are some examples of plugins that have been developed by the Ansible community: – The HashiCorp Vault plugin provides integration with Vault, a popular tool for managing secrets and sensitive data.

– The ACI plugin provides integration with Cisco’s Application Centric Infrastructure (ACI), allowing users to automate tasks related to their network infrastructure. – The VMware NSX-T plugin provides integration with VMware’s NSX-T networking platform, allowing users to automate tasks related to their virtualized infrastructure.

These plugins demonstrate the versatility of Ansible in integrating with different systems and platforms. By leveraging advanced plugin development techniques, users can extend Ansible’s functionality beyond what is provided out-of-the-box, making it a powerful tool for automating tasks across complex infrastructures.

Rarely Known Small Details: Tips and Tricks for Efficient Plugin Development

The Art of Writing Efficient, Reusable, and Maintainable Plugins

Writing efficient, reusable, and maintainable plugins is an art that requires practice and attention to detail. Here are some tips and tricks that will help to make your plugins more efficient: 1. Use caching: Caching is a technique used to store frequently accessed data in memory to reduce processing time.

In Ansible, you can use the cache plugin to cache data generated by your custom plugins. 2. Write concise code: Writing concise code helps to reduce complexity, making it easier to read and understand.

Avoid duplicating code in multiple places; instead, write a separate module or function that can be reused across your entire playbook. 3. Follow best practices: Following best practices such as using proper naming conventions, using descriptive comments, separating concerns into different modules or functions, etc., makes your code more readable and maintainable.

Testing Your Plugins

Testing is essential when it comes to developing software of any kind. Ansible provides a testing framework called testinfra which allows you to write tests for your custom plugins.

Here are some tips on how you can test your plugins: 1. Write functional tests: Functional tests ensure that the plugin works as expected in real-world scenarios.

2. Use unit tests: Unit tests ensure that each function within the plugin works correctly under different conditions. 3. Test edge cases: Testing edge cases (i.e., inputs that lie on the boundary of valid/invalid inputs) helps identify potential issues with the plugin’s functionality.


Plugins play a crucial role in extending Ansible’s functionality by allowing developers to customize their automation workflows easily. Customization through plugins requires knowledge of writing efficient code and familiarity with testing techniques such as functional and unit testing. By following the tips and tricks outlined above, developers can create efficient, reusable, and maintainable plugins that solve specific automation challenges.

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