Ansible Task 1 (configuring Docker)

Task Overview

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 web server

Pre-requisites

• set up one manager node and one managed node
• install ansible in managed node by pip3 install ansible
• configure the ip managed node in a txt file and add that file to ansible config file at /etc/ansible/ansible.cfg
• check if all the managed nodes are pingable by
  ansible all -m ping

File and their explation

Hosts File

• In this file we write all our ip addresses of managed nodes.
  ansible_user: The user name to use when connecting to the host.
  ansible_ssh_pass: managed node password for ssh connection.
• file: myhosts.txt
  location: /etc/myhosts.txt

[test]
192.168.43.89 ansible_user=root ansible_ssh_pass=redhat

[cli]
192.168.43.117 ansible_user=root ansible_ssh_pass=redhat

[gui]
192.168.43.101 ansible_user=root ansible_ssh_pass=redhat

Configuration file

• inventory: where all are host ips are stored
  host_key_checking: it auto saves the ssh key for first time connection.
• File: ansible.cfg
  Location: /etc/ansible/ansible.cfg

[defaults]
inventory=/etc/myhosts.txt
host_key_checking = False

Main code File ( docker.yml )

• Step 1: we define on which set of hosts we want to run the ansible playbook.
• we have set a variable docker for docker full name with version which we will install on our manged node

• Step 2 : adding a yum repo of docker-ce and installing docker
  Note: we have to write full name of docker with version for community edition.
• Installing docker and printing std output

• Step 3: installing python so that we can use pip3 module from python.
  Installing python module of docker from pip3. it is necessary for proper functioning of docker.
• Starting the docker service permanently
• Stoping and disabling the firewalld of rhel
• copying our webapp code from managed node to managed node.

• Step 4 : pulling a docker image from docker hub
• launching a docker container named “httpd_webserver”
• mounting /var/www/html/ from host to container
• exposing port 81 for outside connectivity
• port forwarding port 81 -> 80
• finally printing full details of container just like (docker inspect httpd_webserver)

This is the final output
container is launched and and we can see our webpage.

While making the i faced some some errors of iptables so i m also sharing how i solved those errors.

Thank You