DevOps Classroom notes 26/Feb/2025

Ansible

• Ansible deals with two types of nodes
  • Control Node:
    • This is where we install ansible. This has to be a linux instance
  • Node:
    • This is where we want to deploy applications, This can be any os or even networking devices
      
• We have three inputs that we need to provide to ansible
  • inventory:
    • list of nodes (ip addresses/name)
    • This is mostly static
  • credentials:
    • credential for ansible to login into node and execute configuraions
    • This is also mostly static
  • desired state:
    • What we want
    • This changes from application to application and also across releases in the same application
    • Ways to express desired state:
      • command: This option expects you to express desired state in command line form
      • yaml: This is referred as playbook, where we create a yaml file which is version controlled
• Ansible Product lines:
  • Ansible core: This is free opensource tool
  • Ansible Automation Platform (Paid):
    • Ansible
    • Ansible Tower
      • User Management
      • RBAC
      • Automation Mesh
  • AWX (free ansible tower equivelent): No Redhat support

Ansible Components

• Inventory
• Playbook: Desired state in yaml form
• Module
• Role
• Collection
• Plugin
• Vault
• galaxy

Find me steps to install lamp stack on ubuntu 24.04

• Steps

sudo apt update -y
sudo apt install apache2 -y
sudo systemctl start apache2
sudo systemctl enable apache2
sudo apt install php libapache2-mod-php php-mysql -y
# create a file
echo "<?php phpinfo(); ?>" > /var/www/html/info.php

• Now access http://<ip>/info.php
• Ansible playbook (rough)

---
- name: install lamp
  hosts: all
  become: yes
  tasks:
    - name: install apache
      ansible.builtin.apt:
        name: apache2
        update_cache: yes
        state: present
    - name: enable and start apache
      ansible.builtin.systemd:
        name: apache2
        enabled: yes
        state: started
    - name: create a sample page
      ansible.builtin.copy:
        src: info.php
        dest: /var/www/html/info.php

Ways of Working

• Get the manual commands for doing the configuration and ensure they are working
• For each command try to find how to express desired state
• Now create a inventory, configure credentials, and execute using ansible.

What we need to have

• Cloud Accounts
  • AWS
  • Azure
• Softwares:
  • ssh
  • visual studio code