AWS Dynamic Inventory in Ansible

1. Introduction

AWS Dynamic Inventory allows Ansible to dynamically fetch the inventory of EC2 instances from AWS. This is useful for managing cloud resources where instances may come and go frequently.

2. Key Concepts

**Dynamic Inventory**: A method of using scripts or plugins to generate inventory on-the-fly.
**AWS EC2**: Amazon's Elastic Compute Cloud service allowing scalable virtual servers.
**Ansible**: An open-source automation tool used for configuration management, application deployment, and task automation.

3. Setup

To use AWS Dynamic Inventory, ensure you have the following prerequisites:

Install Ansible: pip install ansible
Install Boto3: pip install boto3
Configure AWS credentials using aws configure.

4. Configuration

To configure dynamic inventory, create a file called aws_ec2.yml:

plugin: aws_ec2
regions:
  - us-east-1
filters:
  instance-state-name: running
keyed_groups:
  - key: tags
    prefix: tag
    separator: '_'

Place this file in the inventory directory of your Ansible project.

5. Usage

To utilize the dynamic inventory, run your Ansible playbooks as follows:

ansible-inventory -i inventory/aws_ec2.yml --graph

This command will display the dynamically generated inventory structure.

6. Best Practices

Always use IAM roles for security when accessing AWS resources.
Limit the number of AWS regions in your configuration to enhance performance.
Regularly update your Ansible and Boto3 versions for compatibility.

7. FAQ

What is dynamic inventory?

Dynamic inventory allows Ansible to retrieve actual server instances from cloud providers instead of using a static list.

Do I need to install any additional plugins for AWS?

No, the AWS EC2 dynamic inventory is included with Ansible, but you need Boto3 installed for AWS API calls.

How do I filter instances in my inventory?

You can apply filters in your inventory configuration file to limit the instances fetched based on tags, states, etc.