Run 'docker volume create' with Ansible?

Question

I have a Rails app I am deploying in Docker containers via Ansible. My app includes three containers so far:

• A Docker volume container (created with docker volume create --name dbdata)
• A Postgres container (with volumes_from dbdata)
• The Rails app container (which links to the postgres container)

My deploy playbook is working, but I had to run the docker volume create command on the server via SSH. I'd love to do that via Ansible, so I could deploy a fresh instance of the app onto an empty container.

Is there a way to run docker volume create via Ansible, or is there some other way to do it? I checked the docs for the Ansible Docker module but it doesn't look like they support volume create yet. Unless I'm missing something?

Answer 1

Here's one option, using the command module.

- hosts: localhost
  tasks:
    - name: check if myvolume exists
      command: docker volume inspect myvolume
      register: myvolume_exists
      failed_when: false

    - name: create myvolume
      command: docker volume create --name myvolume
      when: myvolume_exists|failed

We first check if the volume exists by using docker volume inspect. We save the result of that task in the variable myvolume_exists, and then we only create the volume if the inspect task failed.