Inventory Plugins in Ansible

1. Introduction

Inventory plugins in Ansible are critical for defining the hosts and groups of hosts that Ansible will manage. They allow you to dynamically gather inventory from various sources, making it easier to work with different environments.

2. Key Concepts

• **Static Inventory**: A simple text file listing hosts and groups.
• **Dynamic Inventory**: Automatically generates inventory from external sources (e.g., cloud providers).
• **Inventory Plugin**: A Python script that provides a method to gather hosts dynamically.

3. Types of Inventory Plugins

Ansible provides several built-in inventory plugins. Below are some common types:

1. **Script**: Executes a script to obtain inventory.
2. **YAML**: Uses YAML files for static inventory definition.
3. **INI**: Classic INI format for defining static inventory.
4. **AWS EC2**: Dynamic inventory for AWS EC2 instances.
5. **GCP**: Dynamic inventory for Google Cloud Platform.

4. Configuration

To configure an inventory plugin, you typically define it in your Ansible configuration file. Here’s an example using the AWS EC2 inventory plugin:

                # ansible.cfg
                [defaults]
                inventory = ./inventory/aws_ec2.yaml
                

                # inventory/aws_ec2.yaml
                plugin: aws_ec2
                regions:
                  - us-east-1
                filters:
                  instance-state-name: running
                

5. Best Practices

• Use dynamic inventory plugins for cloud environments to minimize manual updates.
• Organize hosts into groups for better management and targeting.
• Document your inventory setup to facilitate onboarding of new team members.

6. FAQ