Medium : Ansible and the AWS CLI : idempotency example https://medium.com/@tomwwright/ansible-and-the-aws-cli-no-module-no-problem-27580d36ef2d

idempotency.yml

- hosts: localhost
  tasks:

    - name: create an S3 bucket -- we'll see this one is 'changed'
      s3_bucket:
        name: mysupercoolexamplebucket
        region: ap-southeast-2
        state: present


    - name: try and create the S3 bucket again -- we'll see this one is 'ok' because Ansible works out it already exists!
      s3_bucket:
        name: mysupercoolexamplebucket
        region: ap-southeast-2
        state: present