Ansible provision Docker image using Ansible Container which is a package that handles the process of running roles on a Docker container.

Here at Bobcares, we have seen several such Docker related queries as part of our Docker Hosting Support for Docker users, web hosts, and online service providers.

Today we’ll take a look at how to provision docker images using Ansible.

How does Ansible provision Docker container?

Ansible uses “Ansible Container”. It is a package that handles the process of running roles on a Docker container.

In other words, it launches a container called “Conductor“. Also, all the required packages are present in this container. The conductor then connects to the target container and runs the roles. Once, an image is created we can upload it to the Docker hub or any other registry.

Now let’s take a look at how our Support Engineers build Docker Containers using Ansible.

Installing Ansible-Container

To build Docker images, we need to install “Ansible-Container”. By default, it does not ship with Ansible.

1. First, we install Ansible-Container in order to build the Docker images.

pip install ansible-container[docker]

2. Next, we run the command below to verify that it has successfully installed.

ansible-container

It should work without any errors.

After the installation of the Ansible Container, we create our project directory by executing the below commands.

mkdir ansible-container-demo
cd ansible-container-demo
ansible-container init

As a result, the Ansible container will create the below files:

ansible.cfg # override Ansible configs here
ansible-requirements.txt #list python requirements here
container.yml # this is the file which we will use!
meta.yml
requirements.yml
.dockerignore # you know this -.-

Then we will create a directory to hold our roles.

mkdir roles
cd roles
ansible-galaxy init optimize-nginx

Let’s consider “container.yml” as the Docker Compose file. In this file, we will list the roles that we would like to run on our Container.

version: "2"
settings:
conductor:
base: alpine:3.5
project_name: infinitypp
services:
web:
from: nginx:alpine
container_name: nginx-custom
ports:
- "80:80"
roles:
- optimize-nginx
command: ["/usr/sbin/nginx", "-g", "daemon off;"]
dev_overrides:
environment:
- "DEBUG=1"
registries:
docker:
url: https://index.docker.io/v1/
namespace: infinitypp
repository_prefix: ''

This syntax is quite similar to the Docker compose file. We declare our conductor image at the top and then under services, we declare the services. Also, we can have multiple services. However, the most important part is the roles section.

Building the Container

In order to build a container, we need to use:

ansible-container build

This will launch the “conductor” container. After being ready, it will run the Ansible roles to the target container.

Now, that we have our roles executed on the target conductor.

Finally, we run the service:

ansible-container run

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Conclusion

Today, we saw how our Support Engineers provision docker containers using Ansible.