Automate dockerization of webserver using Ansible

Ansible — Configuration Management Tool
Docker — Container Management Tool
Let’s integrate these two to come-up with a wonderful use-case!

What is Docker?

Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers. Containers are isolated from one another and bundle their own software, libraries and configuration files; they can communicate with each other through well-defined channels. While containers as a concept have been around for some time, Docker, an open source project launched in 2013, helped popularize the technology, and has helped drive the trend towards containerization and microservices in software development that has come to be known as cloud-native development.

Docker

Why Docker?

Developing apps today requires so much more than writing code. Multiple languages, frameworks, architectures, and discontinuous interfaces between tools for each lifecycle stage creates enormous complexity. Docker simplifies and accelerates your workflow, while giving developers the freedom to innovate with their choice of tools, application stacks, and deployment environments for each project. Docker enables developers to easily pack, ship, and run any application as a lightweight, portable, self-sufficient container, which can run virtually anywhere. As Bottomley told me, “Containers gives you instant application portability.” In addition, Docker containers are easy to deploy in a cloud.

So, What are we going to deploy here?

We are going to write a playbook that’s gonna perform the following tasks:-

🔅 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 web server

First, let us configure Ansible in the controller node for workability.

• Setup ansible.cfg file

[defaults]
inventory=inventory
host_key_checking=False
command_warnings=False

• Create the inventory containing the IP of the managed node in the same directory as of ansible.cfg file.

<IP of managed node> ansible_ssh_user=root ansible_ssh_pass=redhat

Do check whether Ansible has been configured or not using the command —

ansible --version

Once Ansible is successfully configured, we can go on with creating the ansible playbook: —

---
- name: Setup docker on managed node
  hosts: all
  tasks:
  - name: Configure docker repo
    yum_repository:
      name: docker
      description: Yum repo for docker
      baseurl: https://download.docker.com/linux/centos/7/x86_64/stable/
      gpgcheck: no
- name: Install docker
    command: yum install docker-ce --nobest -y
    ignore_errors: yes
- name: Install python3
    package:
      name: python3
      state: present
- name: Install docker SDK
    pip:
      name: docker-py
- name: Start and enable docker service
    service:
      name: docker
      state: started
      enabled: yes
- name: Pull docker image
    docker_image:
      name: httpd
      source: pull
- name: Create workspace directory
    file:
      path: /root/ansible-task-1
      state: directory
- name: Copy webpage content
    copy:
      content: "This webpage is configured inside a docker container deployed using Ansible."
      dest: /root/ansible-task-1/index.html
- name: Stop firewall services
    service:
      name: firewalld
      state: stopped
- name: Run a docker container
    docker_container:
      name: webos
      image: httpd
      state: present
      exposed_ports:
      - 80/tcp
      - 80/udp
      published_ports:
      - 0.0.0.0:8081:80/tcp
      - 0.0.0.0:8081:80/udp
      volumes:
      - /root/ansible-task-1/:/usr/local/apache2/htdocs/

Seems good to go :)

• Let’s deploy the playbook now —

ansible-playbook <playbook_name>.yml

Playbook run

From the playbook, its evident that we have exposed our docker container to port number 8081. So, let’s check whether the webserver has been containerized or not —

http://<IP of managed node>:8081

Voila! Deployment successful :D

That’s all for this practical guys, than you for a read!