Automating Docker Deployment with Ansible: A Step-by-Step Guide

So our Agenda here is like this

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

🔹 Copy the html code in /var/www/html directory and start the web server

🔹 Run the docker container and expose it to the public

Before writing the ansible playbook let’s configure the ansible configuration file and the inventory file -

• So, at first we have to setup the ansible configuration file which is /etc/ansible/ansible.cfg

$ vim /etc/ansible/ansible.cfg

we simply have to put the location of the inventory file in this ansible.cfg like this

• Now we will update the ip in the inventory file.

$ vim /root/ip.txt

• We can check the host is configured or not by listing the hosts, using this command:

$ ansible all --list-hosts

• Now we can check the connectivity of the worker node using this command:

$ ansible all -m ping

So the setup is ready, now we can write the ansible playbook.

- name: "configuring httpd on docker"
  hosts: web
  
  tasks:
     # from here we will write all the modules as per our requirement

• For the docker configuration first we have to configure the yum

- name: "Yum configuration of Docker"
    yum_repository:
 
      name: docker
      description: "docker repository"
      baseurl: https://download.docker.com/linux/centos/7/x86_64/stable/
      gpgcheck: no

• for installing docker-ce

- name: "Installing docker"

command: “yum install docker-ce — nobest -y”

• Start and enable Docker services

- name: "Docker service start and enable"
      service:
        name: docker
        state: started
        enabled: yes

• Install docker library

- pip:
        name: "docker"
  
        state: latest

• Pull the httpd server image from the Docker Hub

- name: "Pulling httpd image from docker hub"
      docker_image:
        name: httpd
        source: pull

state: present

• Creating a folder in the controller node named /var/www/html

- name: "Creation of a directory"
     file:
        path: "/var/www/html"

state: directory

• Copying the html file to that location (create a index.html file to the same directory where you are creating this ansible playbook) for

- name: "copping html file"
     copy:
        src: "index.html"

dest: "/var/www/html/index.html"

• Enabeling the firewalld

- name: "firewall for port 80"
      firewalld:
        port: "80/tcp"
        state: enabled
        permanent: yes

immediate: yes

• Running the docker container

- name: "Launching docker container"
      docker_container:
        name: webserver
        image: httpd
        state: started
        ports: "8081:80"
        volumes: /var/www/html/index.html:/usr/local/apache2/htdocs/index.html

detach: true

That’s all! Now we have to run the playbook

$ ansible-playbook docker-httpd.yml

we can see the apache httpd webserver is conigured:

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