Automate Docker With Ansible for launching WebServer

Task Description:

Write an Ansible PlayBook that does the following operations in the managed nodes:

• Configure Docker.
• Start and enable Docker services.
• Pull the Httpd server image from the Docker Hub.
• Run the Httpd container and expose it to the public.
• Copy the HTML code in /var/www/html directory and start the webserver.

Variables:

These are the variables which we use in our playbook.

vars:
    - image_name: httpd
    - file: home.html
    - docker_volume: /webpage/
    - docker_host_port: 8080
    - docker_container_port: 80

• Configure Docker:

For this, we need to Configure Docker Repo First…

- name: Add Yum Repo
      yum_repository:
        name: docker
        description: Docker Yum Repo
        baseurl: https://download.docker.com/linux/centos/7/x86_64/stable/
        gpgcheck: no

Install Docker Task…

Redhat by default don’t provide Docker Software now. So we need — nobest option in command for installing Docker.

In ansible, Yum module in Ansible doesn’t have this argument till yet, so I use the command module for doing the installation.

- name: Install Docker-CE
      command: yum install -y  docker-ce --nobest

nstall Docker Requirement on hosts…

We need docker-py module to run docker from ansible tool.

- name: Install Docker Requirement On Host
      command: pip3 install docker-py

• Start and Enable Docker service:

This task start and enable the Docker Service in hosts.

- name: start docker services
      service:
        name: "docker"
        state: started
        enabled: yes

• Pull the Httpd Image from Docker Hub:

This task pulls the docker image to launch the Container.

- name: pull an image
      docker_image:
        name: "{{ image_name }}"
        source: pull

• Task for Copy Html code from controller node to managed Node:

- name: Copy HTML code to Hosts
      template:
        src: "{{ file }}"
        dest: "{{ docker_volume }}"

This code copy the HTML file to the managed Node.

• Launch the Container and exposed it to outer world:

- name: Run docker container
      docker_container:
        name: webserver
        image: "{{ image_name }}"
        interactive: yes
        volumes: 
          - "{{ docker_volume }}:/usr/local/apache2/htdocs"
        ports:
          - "{{ docker_host_port }}:{{ docker_container_port }}"
        command: httpd -D FOREGROUND

Final PlayBook:

When put the above code in one file…

- hosts: web
  vars:
    - image_name: httpd
    - file: home.html
    - docker_volume: /webpage/
    - docker_host_port: 8080
    - docker_container_port: 80
  tasks:
    - name: Add Yum Repo
      yum_repository:
        name: docker
        description: Docker Yum Repo
        baseurl: https://download.docker.com/linux/centos/7/x86_64/stable/
        gpgcheck: no
    - name: Install Docker-CE
      command: yum install -y  docker-ce --nobest
    - name: start docker services
      service:
        name: "docker"
        state: started
        enabled: yes
    - name: Install Docker Requirement On Host
      command: pip3 install docker-py
    - name: pull an image
      docker_image:
        name: "{{ image_name }}"
        source: pull
    - name: Copy HTML code to Hosts
      template:
        src: "{{ file }}"
        dest: "{{ docker_volume }}"
    - name: Run docker container
      docker_container:
        name: webserver
        image: "{{ image_name }}"
        interactive: yes
        volumes: 
          - "{{ docker_volume }}:/usr/local/apache2/htdocs"
        ports:
          - "{{ docker_host_port }}:{{ docker_container_port }}"
        command: httpd -D FOREGROUND

Running the PlayBook:

Command for run playbook…

ansible-playbook webserver.yaml