Docker and ansible

Docker with Ansible 

Docker is a popular platform for building, shipping, and running distributed applications. Ansible, on the other hand, is a powerful automation tool that can be used to manage infrastructure and application deployments. Together, Docker and Ansible provide a powerful combination for managing and automating container-based deployments.

One way to use Ansible with Docker is by using the Docker modules provided by Ansible. These modules allow you to manage Docker containers, images, and networks from within your Ansible playbooks. For example, you can use the docker_container module to create, start, stop, or delete Docker containers, and the docker_image module to build or push Docker images.

Another way to use Ansible with Docker is by using Ansible roles specifically designed for Docker deployments. These roles provide a set of pre-defined tasks and variables for common Docker-related operations, such as creating a Docker swarm, deploying a Docker stack, or managing Docker secrets.

Examples on using Ansible with Docker:

1. Installing Docker with Ansible: You can use Ansible to install Docker on your target hosts. Ansible provides the docker_installation module that can install Docker and its dependencies on various Linux distributions.
2. Managing Docker containers: With Ansible's docker_container module, you can manage Docker containers from within your Ansible playbooks. You can create, start, stop, or remove containers, as well as specify container configurations like environment variables, volumes, and network settings.
3. Building Docker images: Ansible's docker_image module allows you to build Docker images from source code or Dockerfiles. You can also push images to Docker registries using the docker_login and docker_push modules.
4. Managing Docker networks: You can create and manage Docker networks using Ansible's docker_network module. This module allows you to create overlay networks for Docker swarm mode, as well as configure network drivers, subnets, and gateway addresses.
5. Using Ansible roles: Ansible provides a collection of community-maintained roles that can help you manage Docker deployments more easily. These roles provide pre-defined tasks, templates, and variables for common Docker operations. For example, the geerlingguy.docker role can install and configure Docker on a host, while the angstwad.docker_ubuntu role can create Docker containers and images on Ubuntu.
6. Using Docker with Ansible Tower: Ansible Tower is the web-based interface for managing Ansible playbooks, inventories, and job runs. Tower can also integrate with Docker, allowing you to provision and manage Docker containers using Tower workflows and inventory sources. For example, you can use Tower to orchestrate the deployment of Docker containers across multiple hosts, or to perform rolling updates of a Docker service.

Few Examples of using ansible for docker

 Creating a Docker container:

- name: Create a Docker container

  hosts: all

  become: true

  vars:

    container_name: mycontainer

    image_name: ubuntu:latest

  tasks:

    - name: Pull Docker image

      docker_image:

        name: "{{ image_name }}"

        state: present

    - name: Create Docker container

      docker_container:

        name: "{{ container_name }}"

        image: "{{ image_name }}"

        state: started

 This playbook creates a Docker container named mycontainer based on the ubuntu:latest image. It pulls the image if it doesn't exist and starts the container.

2.      Building a Docker image:

- name: Build a Docker image

  hosts: all

  become: true

  vars:

    image_name: myimage

    dockerfile_path: /path/to/Dockerfile

  tasks:

    - name: Build Docker image

      docker_image:

        build:

          path: "{{ dockerfile_path }}"

          tag: "{{ image_name }}"

 

This playbook builds a Docker image using the Dockerfile located at /path/to/Dockerfile, and tags it as myimage.

 

3.      Managing Docker networks:

- name: Create a Docker network

  hosts: all

  become: true

  vars:

    network_name: mynetwork

  tasks:

    - name: Create Docker network

      docker_network:

        name: "{{ network_name }}"

        state: present

 

This playbook creates a Docker network named mynetwork using the docker_network module.

4.      Using Ansible roles:

- name: Deploy a Docker stack

  hosts: swarm

  become: true

  roles:

    - geerlingguy.docker

  vars:

    stack_name: myapp

    stack_file: /path/to/docker-compose.yml

  tasks:

    - name: Deploy Docker stack

      docker_stack:

        name: "{{ stack_name }}"

        compose_file: "{{ stack_file }}"

 

This playbook deploys a Docker stack named myapp using the geerlingguy.docker role. It specifies the location of the docker-compose.yml file and deploys the stack to a Docker swarm cluster.

5.      Using Docker with Ansible Tower:

In Ansible Tower, you can create a workflow that provisions and manages Docker containers. For example, you can create a workflow that:

• Launches a Docker container on a host
• Performs a health check on the container
• Configures the container with environment variables, volumes, and network settings
• Monitors the container for resource utilization and errors

We can also create inventory sources in Ansible Tower that discover Docker containers and services across your infrastructure. This allows to manage your Docker deployments from a single interface and automate common operations, such as rolling updates and scaling.

Overall, using Ansible with Docker provides a powerful combination for managing container-based deployments. Whether deploying a single container or a complex Dockerized application, Ansible can help streamline the deployment processes, achieve greater consistency, and reliability in  infrastructure management.