Automating Docker Installation and Container Deployment

This project uses Ansible to automate the installation of Docker on a group of servers and deploy a simple Docker container.

Prerequisites

1. Ansible Installed: Ensure Ansible is installed on your control node (the machine from which you'll run Ansible).

   To Install Ansible on a Red Hat-based system:

   sudo yum install epel-release -y
   sudo yum install ansible -y

2. SSH Access: Ensure you have SSH access to all target servers where Docker will be installed. Setting up SSH keys for passwordless access is recommended.

Project Setup

Step 1: Set Up Your Ansible Environment

1. Verify Ansible Installation:

   ansible --version

2. Set Up SSH Access:

   • Make sure you have SSH access to the target servers. You might need to configure SSH keys for passwordless login.

Step 2: Create Your Inventory File

1. Create an Inventory File:
   • Create a file named hosts in your project directory with the following content:

   [docker_hosts]
   server1.example.com
   server2.example.com

   • Replace server1.example.com and server2.example.com with the actual hostnames or IP addresses of your target servers.

Step 3: Write the Ansible Playbook

1. Create a Playbook File:

   • Create a file named setup_docker.yml in your project directory with the following content:

   ---
   - name: Install Docker and run a container
     hosts: docker_hosts
     become: yes
   
     tasks:
       - name: Install required system packages
         yum:
           name: "{{ item }}"
           state: present
         loop:
           - yum-utils
           - device-mapper-persistent-data
           - lvm2
   
       - name: Add Docker repository
         command: >
           yum-config-manager --add-repo
           https://download.docker.com/linux/centos/docker-ce.repo
         args:
           creates: /etc/yum.repos.d/docker-ce.repo
   
       - name: Install Docker
         yum:
           name: docker-ce
           state: present
           enablerepo: docker-ce-stable
   
       - name: Start and enable Docker
         service:
           name: docker
           state: started
           enabled: yes
   
       - name: Run a simple Docker container (Hello World)
         docker_container:
           name: hello-world
           image: hello-world
           state: started

   Explanation of Playbook:

   • Install Required Packages: Installs necessary system packages for Docker.
   • Add Docker Repository: Adds the official Docker repository to the system so that Docker can be installed.
   • Install Docker: Installs Docker from the added repository.
   • Start and Enable Docker: Starts Docker service and ensures it starts on boot.
   • Run a Docker Container: Pulls the hello-world Docker image and runs it to test Docker installation.

Step 4: Run Your Ansible Playbook

1. Execute the Playbook:

   • Run the playbook using the following command:

   ansible-playbook -i hosts setup_docker.yml

   • This command tells Ansible to use the hosts inventory file and run the tasks defined in the setup_docker.yml playbook on the servers listed under the [docker_hosts] group.

2. Verify Docker Installation and Container Execution:

   • SSH into one of your servers and check if Docker is running:

   systemctl status docker

   • To verify that the hello-world container ran successfully, use:

   docker ps -a

Step 5: Customize and Extend Your Ansible Project

• Deploy Different Docker Containers: Modify the playbook to deploy different Docker containers or services as needed.
• Create Docker Networks: Use Ansible to create Docker networks if your containers need to communicate with each other.
• Use Docker Compose: Extend the playbook to install Docker Compose and deploy multi-container applications using Compose files.

Conclusion

This project demonstrates how to automate the installation of Docker and the deployment of a simple Docker container using Ansible. Feel free to extend this project to suit your needs for managing Docker across multiple servers.