Module 1: Ansible Fundamentals - Understanding the Basics

• What is Ansible?

  • Explanation of Ansible as a powerful open-source automation engine that helps you with configuration management, application deployment, task automation, and IT orchestration.
  • Emphasis on its simplicity, human-readable syntax (YAML), and power.

• Agentless Architecture:

  • Detailed explanation of Ansible's agentless nature. It connects to your managed nodes (hosts) via SSH (for Linux/Unix) or WinRM (for Windows) and executes tasks without requiring any software to be installed on the managed nodes beforehand. This simplifies setup and maintenance.

• YAML Syntax:

  • Introduction to YAML (YAML Ain't Markup Language) as the human-friendly data serialization standard used by Ansible for defining playbooks, variables, and inventory.

  • Explanation of basic YAML syntax: key-value pairs, lists, indentation (spaces are crucial!), comments.

  • Example YAML:

    ---
    - name: Sample Playbook
      hosts: webservers
      tasks:
        - name: Ensure Nginx is installed
          apt:
            name: nginx
            state: present
    
    

• Inventory Files:

  • Explanation of the Ansible inventory file, which lists the managed hosts.

  • Basic inventory file structure: specifying hostnames or IP addresses.

  • Example Inventory (/etc/ansible/hosts or a custom file):

    [webservers]
    webserver01.example.com
    webserver02.example.com
    
    [dbservers]
    dbserver01.example.com ansible_host=192.168.1.10
    
    [all:vars]
    ansible_user=ubuntu
    ansible_private_key_file=~/.ssh/id_rsa
    
    

  • Explanation of host-specific variables (e.g., ansible_host for specifying a different connection address, ansible_user for the SSH user).

• Hosts Configuration:

  • How Ansible uses the inventory to target specific hosts or groups of hosts.
  • Understanding the all group and custom-defined groups.

• Command-Line Usage:

  • Introduction to the ansible command for running ad-hoc tasks and the ansible-playbook command for executing playbooks.
  • Basic options for the ansible command: i (inventory file), m (module), a (arguments), u (remote user), k (prompt for SSH password).

• Hands-on Lab:

  1. Install Ansible on your control node (your local machine or a dedicated server).
  2. Create a simple inventory file with a few target hosts (you can use Vagrant or cloud instances for this).
  3. Configure SSH access to your target hosts from the control node using SSH keys.
  4. Run basic ad-hoc commands (covered in the next module) to verify connectivity.

Module 2: Running Ad-Hoc Commands - Quick Automation Tasks

• Targeting Specific Hosts:

  • Using the i flag to specify your inventory file.
  • Using host patterns to target specific hosts or groups (e.g., webservers, dbservers, web*, !webserver02.example.com).

• Module Usage:

  • Introduction to Ansible modules as reusable units of code that perform specific tasks.
  • Using the m flag to specify the module to use.
  • Passing arguments to modules using the a flag (key=value pairs).

• Common Ad-Hoc Modules:

  • ping: Verifies connectivity to the target hosts.

    ansible all -i inventory.ini -m ping
    
    

  • copy: Copies files from the control node to the target hosts.

    ansible webservers -i inventory.ini -m copy -a "src=/path/to/local/file dest=/path/on/remote/host"
    
    

  • apt (for Debian/Ubuntu) / yum (for CentOS/RHEL): Manages packages on the target hosts.

    ansible webservers -i inventory.ini -m apt -a "name=nginx state=present"
    ansible dbservers -i inventory.ini -m yum -a "name=mariadb-server state=installed"
    
    

  • user: Manages user accounts on the target hosts.

    ansible all -i inventory.ini -m user -a "name=deploy useradd=yes state=present"
    
    

  • command: Executes arbitrary commands on the target hosts. Use with caution, as it doesn't guarantee idempotence.

    ansible webservers -i inventory.ini -m command -a "ls -l /var/www/html"
    
    

  • file: Manages files and directories (creation, deletion, permissions).

    ansible all -i inventory.ini -m file -a "path=/tmp/my_directory state=directory owner=deploy group=deploy mode=0755"
    
    

• Command-Line Usage: Emphasize the flexibility of ad-hoc commands for quick tasks and troubleshooting.

• Hands-on Lab:

  1. Use ad-hoc commands to ping your target hosts.
  2. Copy a simple text file to your target hosts.
  3. Install a package (e.g., htop) on your target hosts using the appropriate package manager module.
  4. Create a new user on your target hosts.
  5. List the contents of a directory on your target hosts.

Module 3: Writing Playbooks - Orchestrating Automation

• Structure of Tasks:
  • Explanation of tasks as the building blocks of playbooks. Each task calls a specific Ansible module.
  • Basic task structure: name (description), module: arguments.
• Handlers:
  • Special tasks that are executed only when explicitly notified by another task (using the notify keyword). Useful for triggering service restarts after configuration changes.
• Variables:
  • Defining and using variables within playbooks to make them more dynamic and reusable.
  • Variable sources: playbook-level, host vars, group vars.
• Conditional Execution:
  • Using the when keyword to execute tasks only if a specific condition is met (based on facts or variables).
• Loops:
  • Iterating over lists of items using the loop keyword to perform the same task multiple times with different parameters.