How To Install Docker Using Ansible

In this post, we will explore how to install Ansible on a macOS and use it to install Docker. Ansible is a powerful automation tool that allows for managing server and application configuration in an organized and repeatable manner.

Step 1: Installing Ansible on macOS
The simplest way to install Ansible on macOS is using Homebrew, the package manager for macOS. Open your terminal and type:

brew install ansible

# or use docker image to run playbook, example:
docker run --rm -it -v $PWD:/app -v ~/.ssh/id_rsa:/root/.ssh/id_rsa alpinelinux/ansible ansible-playbook -i app/inventory.ini app/playbooks/docker.yml

Step 2: Configuring Ansible
Prepare an inventory.ini file, which will contain the IP addresses of the machines where you want to execute Ansible tasks. Here’s a sample content for the file:

[all]
# In this case, node1 is the hostname with 192.168.18.131 IP address and garis is sudo user.
node1 ansible_host=192.168.18.131 ansible_user=garis ansible_ssh_common_args='-o StrictHostKeyChecking=no'

Step 3: Creating the Ansible Playbook for Docker Installation
Next, create a playbook named docker.yml under a directory named playbooks. This playbook will contain all the necessary tasks to install Docker on a remote Ubuntu server. The playbook looks like this:

---
- name: Install Docker on Ubuntu
  hosts: all
  remote_user: garis  # Change remote user to your sudo user!
  become: true
  vars:
    arch_mapping:  # Map ansible architecture {{ ansible_architecture }} names to Docker's architecture names
      x86_64: amd64
      aarch64: arm64

  tasks:
    - name: Update and upgrade all packages to the latest version
      ansible.builtin.apt:
        update_cache: true
        upgrade: dist
        cache_valid_time: 3600

    - name: Install required packages
      ansible.builtin.apt:
        pkg:
          - apt-transport-https
          - ca-certificates
          - curl
          - gnupg
          - software-properties-common

    - name: Create directory for Docker's GPG key
      ansible.builtin.file:
        path: /etc/apt/keyrings
        state: directory
        mode: '0755'

    - name: Add Docker's official GPG key
      ansible.builtin.apt_key:
        url: https://download.docker.com/linux/ubuntu/gpg
        keyring: /etc/apt/keyrings/docker.gpg
        state: present

    - name: Print architecture variables
      ansible.builtin.debug:
        msg: "Architecture: {{ ansible_architecture }}, Codename: {{ ansible_lsb.codename }}"

    - name: Add Docker repository
      ansible.builtin.apt_repository:
        repo: >-
          deb [arch={{ arch_mapping[ansible_architecture] | default(ansible_architecture) }}
          signed-by=/etc/apt/keyrings/docker.gpg]
          https://download.docker.com/linux/ubuntu {{ ansible_lsb.codename }} stable
        filename: docker
        state: present

    - name: Install Docker and related packages
      ansible.builtin.apt:
        name: "{{ item }}"
        state: present
        update_cache: true
      loop:
        - docker-ce
        - docker-ce-cli
        - containerd.io
        - docker-buildx-plugin
        - docker-compose-plugin

    - name: Add Docker group
      ansible.builtin.group:
        name: docker
        state: present

    - name: Add user to Docker group
      ansible.builtin.user:
        name: "{{ ansible_user }}"
        groups: docker
        append: true

    - name: Enable and start Docker services
      ansible.builtin.systemd:
        name: "{{ item }}"
        enabled: true
        state: started
      loop:
        - docker.service
        - containerd.service

This playbook includes various tasks such as updating packages, installing required dependencies, adding Docker’s GPG key, setting up the Docker repository, installing Docker and related packages, adding a Docker group, and ensuring the Docker service is enabled and running.

Step 4: Running the Playbook
Finally, you can run the playbook using the following command:

ansible-playbook -i inventory.ini playbooks/docker.yml

# or use docker
docker run --rm -it -v $PWD:/app -v ~/.ssh/id_rsa:/root/.ssh/id_rsa alpinelinux/ansible ansible-playbook -i app/inventory.ini app/playbooks/docker.yml

This command will execute the playbook on the hosts specified in your inventory.ini file, effectively installing Docker on them.

Conclusion
By following these steps, you’ve successfully installed Ansible on your macOS laptop and used it to automate the installation of Docker on a remote server. This showcases the power and simplicity of Ansible for automating tasks across different systems.