Idempotency in amazon..aws.ec2

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1

Hi ansible squad!

I’ve been using amazon.aws.ec2 (or community.aws.ec2_instance - ive been switching back and forth) to ensure there is an ec2 instance created for each {{ inventory_hostname }} by using tags. It doesn’t seem to work.

Every time I run the playbook with the below play, it just creates a new ec2 instance? How can I make it more idempotent? If the instance already exists, dont create a new one?

Preferably without other plays?

  • name: Ensure EC2 instance exists
    amazon.aws.ec2:
    aws_access_key: ‘{{ aws_access_key }}’
    aws_secret_key: ‘{{ aws_secret_key }}’
    region: ‘{{ aws_region }}’
    image: ‘{{ aws_ec2_ami }}’
    instance_type: ‘{{ aws_instance_type_web }}’
    vpc_subnet_id: ‘{{ aws_subnet_id }}’
    group: ‘SG-{{ environment_designator }}’
    key_name: ‘Keypair-{{ environment_designator }}’
    instance_tags:
    Mytag.MyEnvironment: “”
    Mytag.MyEnvironment.Environment: ‘{{ environment_designator }}’
    Mytag.MyEnvironment.Roles: web1
    Mytag.MyEnvironment.Hostname: ‘{{ inventory_hostname }}’
    wait: yes
    assign_public_ip: no
    register: ec2_instances
    delegate_to: localhost
2

You should supply an ‘id’ parameter:

https://docs.ansible.com/ansible/latest/collections/amazon/aws/ec2_module.html#parameter-id

3

That… makes sense. I should have ctrl-f ‘idempotency’ on the module documentation. I’ll give it a try, thanks for the help!