What is Ansible?

Ansible is an open-source, easy-to-use tool for automating IT infrastructure. It is used for configuring servers, deploying applications, and orchestrating tasks.

Key features:

• Agentless: Does not require installation of agents on managed nodes. Uses SSH (or WinRM for Windows).
• Idempotent: Operations can be repeated multiple times without changing the final state if it is already achieved.
• Simplicity: Uses YAML for writing playbooks, making it readable and understandable.
• Modules: Comes with a large number of modules for performing various tasks (installing packages, copying files, managing services, etc.).
• Extensibility: Easily create your own modules and plugins.

Main components:

• Control Node: The server from which Ansible commands and playbooks are run. Usually Linux.
• Managed Nodes: Servers or devices that you manage with Ansible.
• Inventory: A file describing your managed nodes (IP addresses, hostnames, groups).

  [webservers]
  web1.example.com
  web2.example.com
  
  [databases]
  db1.example.com
  

• Modules: Modules are actual units of code that perform specific tasks on managed nodes.

  - name: Install Nginx
    ansible.builtin.apt:
      name: nginx
      state: present
  

• Tasks: A task is a call to a module with specific parameters. Tasks are executed sequentially.
• Playbooks: Playbooks are YAML files containing a set of tasks to achieve a specific goal. They describe the desired state of the system.

  ---
  - name: Configure production web servers
    hosts: webservers
    become: yes  # Run tasks with sudo rights
    tasks:
      - name: Install latest version of Apache
        ansible.builtin.yum:
          name: httpd
          state: latest
      - name: Ensure Apache is running and enabled on boot
        ansible.builtin.service:
          name: httpd
          state: started
          enabled: yes
  

• Roles: Roles gather tasks, variables, and templates into reusable structures.

Applications:

• Configuration management.
• Application deployment.
• Infrastructure provisioning (e.g., configuring virtual machines after creation).
• Task orchestration (sequential execution of actions on different nodes).
• Automation of routine operations.