Introduction

Dynamic inventory plugins are a built-in feature of Ansible that allows users to generate inventory dynamically by querying external sources such as cloud providers, virtualization platforms, or configuration management databases. These plugins leverage Ansible's plugin architecture to extend its functionality and seamlessly integrate dynamic inventory generation into automation workflows. In this article, we'll explore how to use dynamic inventory plugins in Ansible and the benefits they provide.

Using Built-in Dynamic Inventory Plugins

Ansible provides several built-in dynamic inventory plugins that can be used out of the box to generate inventory dynamically. These plugins are categorized based on the source they query, such as cloud providers (e.g., AWS, Azure), virtualization platforms (e.g., VMware, OpenStack), or configuration management databases (e.g., LDAP, Consul).

Example:

# Using AWS dynamic inventory plugin
plugin: aws_ec2
regions:
  - us-west-1

In this example, the aws_ec2 dynamic inventory plugin is used to generate inventory dynamically from Amazon EC2 instances in the us-west-1 region.

Creating Custom Dynamic Inventory Plugins

In addition to built-in plugins, Ansible allows users to create custom dynamic inventory plugins to query external sources not covered by the built-in plugins. Custom plugins are written in Python and leverage Ansible's plugin architecture to extend its functionality.

Example:

from ansible.plugins.inventory import BaseInventoryPlugin

class MyCustomInventoryPlugin(BaseInventoryPlugin):
    def parse(self, inventory, loader, path, cache):
        # Custom logic to query external source and generate inventory dynamically
        # Populate 'inventory' object with hosts and groups
        pass

Benefits of Dynamic Inventory Plugins

1. Ease of Use: Dynamic inventory plugins provide a seamless way to generate inventory dynamically without the need for external scripts or manual intervention.

2. Flexibility: Custom dynamic inventory plugins offer flexibility in querying external sources and generating inventory tailored to specific infrastructure environments.

3. Integration: Dynamic inventory plugins seamlessly integrate with Ansible playbooks and automation workflows, allowing for dynamic targeting of hosts based on their attributes or tags.

Conclusion

Dynamic inventory plugins are a powerful feature of Ansible that enable users to generate inventory dynamically from external sources. Whether using built-in plugins or creating custom plugins, dynamic inventory plugins streamline automation workflows, enhance flexibility, and ensure real-time updates, ultimately leading to more efficient and reliable infrastructure management.