Docker Setup through Ansible Using Role in 6 Easy Steps

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Table of Contents

Introduction

Docker setup through Ansible using roles is an efficient method to configure Docker environments using Ansible roles. This guide simplifies the intricate process of deploying and managing Docker by leveraging Ansible’s role-based automation. By breaking down complex tasks into modular roles, this approach ensures a structured and streamlined Docker setup across multiple hosts.

The guide elucidates step-by-step procedures, illustrating the creation and utilization of Ansible roles to seamlessly install Docker, manage containers, set configurations, and maintain consistency. Through this comprehensive yet straightforward guide, users gain insight into orchestrating Docker environments efficiently with Ansible’s versatile role-based automation.

Prerequisites:

Learn the role in Ansible in more depth from my post
Learn Docker.

Please follow the below steps for Docker setup through Ansible Using roles

Step 1 – Init docker-setup role

Use the script below to initialize the docker-setup role

# Go to Ansible root directory
cd /path/to/ansible

# Go inside roles directory
cd roles

# Create docker setup role
ansible-galaxy role init docker-setup

Step 2 – Remove unnecessary default files and directories

Use the below command to remove unused default files and directories

rm -rf README.md files meta templates tests vars

Step 3 – Add the below content into tasks/main.yml and handlers.yml

Overwrite tasks/main.yml with below content

# tasks file for docker

- name: Install dependencies
  apt:
    name:
      - apt-transport-https
      - ca-certificates
      - curl
      - software-properties-common
    update_cache: yes

- name: Add Docker GPG key
  apt_key:
    url: https://download.docker.com/linux/ubuntu/gpg

- name: Add Docker APT repository
  apt_repository:
    repo: 'deb [arch=amd64] https://download.docker.com/linux/ubuntu {{ ansible_distribution_release }} stable'
    state: present

- name: Install Docker
  apt:
    name: docker-ce
    state: present
    update_cache: yes
  notify: Restart Docker service

- name: Add {{user}} user to docker group to enable this user can run docker commands without sudo
  user:
    name: '{{user}}'
    groups: docker
    append: yes

Overwrite handlers/main.yml with below content

# handlers file for docker
- name: Restart Docker service
  service:
    name: docker
    state: restarted

Step 4 – Create docker-setup.yml playbook with the below contents

- name: Docker setup
  hosts: docker_servers
  become: yes
  roles:
    - roles/docker-setup

Please add other roles also as per your need

Step 5 – Add docker_servers group(optional) in inventory file

Let us assume you have inventory file inventories/backend_servers.yml

# backend_servers.yml
all:
  children:
    docker_servers:
      hosts:
        prod-docker-01:
        prod-docker-02:
  vars:
    system_user: ubuntu
    user: {{system_user}} # user is a dynamic variable whose value is assignd to the value of system_user

Please make sure prod-docker-01 is accessible through SSH.

Step 6 – Execute docker-setup.yml playbook

# First execute docker-setup playbook in check mode to identify and resolve any issues (e.g syntax issue, undefined variable issues)
ansible-playbook docker-setup.yml -i inventories/backend_servers.yml -l prod-docker-01 --check

# After identifying and fixing issues in the above step, we should execute it first on one host
ansible-playbook docker-setup.yml -i inventories/backend_servers.yml -l prod-docker-01 -v

# If playbook executes successfully on one host then we should execute it on all hosts
ansible-playbook docker-setup.yml -i inventories/backend_servers.yml -vv

Note: Increase verbosity in the above command with –vv or –vvv in case you run into any issues.

Key Takeaways from this post

How to develop a docker-setup role in Ansible.
How to create a docket-setup playbook and its inventory file
How to execute a playbook

Frequently Asked Questions

Q1 – Where should I add default variables related to the docker-setup role?

Answer – Ansible creates a defaults/main.yml file when we create a role. This file is meant for putting default variables (e.g. docker_version).

Conclusion

In conclusion, utilizing Ansible’s roles for Docker setup streamlines the deployment, configuration, and maintenance processes with remarkable efficiency. This approach, outlined in the guide, simplifies complex tasks by organizing them into modular roles, ensuring consistency and scalability across diverse environments.

By employing Ansible’s role-based automation, users achieve a structured and reproducible Docker setup, enabling swift provisioning and management of containers. The guide’s step-by-step instructions empower users to orchestrate Docker environments seamlessly, from initial installation to configuration and ongoing maintenance.

Embracing Ansible roles for Docker not only enhances productivity but also promotes standardization and reliability, making it an invaluable tool for orchestrating containerized applications and infrastructure with ease.

Enjoy the post!!

Editorial Team

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