In my previous article, I discussed the utility Ansible and other similar tools provides developers. For this post, I’ll be covering the command modules I used to create an Ansible playbook that provisions a Docker container to run a test application. I’ll also add a few other modules that I find very useful for playbook writing.

Using Proper Ansible Modules

Note: I’ll be using a Docker container running Ubuntu 18.04 but this playbook is compatible with local systems or cloud computing instances running Ubuntu. Just ensure that localhost and any other proper ports are accessible.

Aside from understanding the finicky nature of Ansible’s syntax, you’ll want to start by understanding the modules. For this example, we’ll be using a module that runs the test application on localhost.

In the image above, you’ll notice a parameter hosts:. It’s important to understand that when you run an Ansible playbook you must choose which managed nodes or groups you want to execute against. You can set a list of hosts in an inventory. The default location for inventory is in a file called /etc/ansible/hosts but you can pull sources of inventory from other sources whether it’d be from the cloud or a hosts.ini file. We won’t be declaring our hosts in a hosts.ini file but it’s good to utilize when creating a playbook that will run in multiple webservers.

Moving on, we’ll set the hosts: parameter as localhost as we want our playbook to execute against localhost. We don’t have to define localhost in our inventory, as Ansible will create an implicit one automatically.