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Notes about Ansible

Table of Contents

Basic Concepts and Terms

  • Host: A remote machine managed by Ansible.

  • Group: Several hosts grouped together that share a common attribute.

  • Inventory: A collection of all the hosts and groups that Ansible manages.

    • Usually stored as inventory.yml
    • Could be a static file in the simple cases or we can pull the inventory
      from remote sources, such as cloud providers.

  • YAML: The file format used for Ansible inventories and playbooks.

  • Roles: Redistributable units of organization that allow users to share automation code easier.

    • Roles are similar to classes in OOP languages. They have the same tasks, variables, and handlers.
  • Playbooks: An ordered list of tasks along with its necessary parameters that define a recipe to configure a system.
  • Modules: Units of code that Ansible sends to the remote nodes for execution.
  • Tasks: Units of action that combine a module and its arguments along with some other parameters.

Most Common Ansible Tools

  • ansible: Run ad-hoc commands on hosts.
  • ansible-playbook: Execute structured automation workflows via YAML playbooks.
  • ansible-doc: Look up documentation for modules and plugins.
  • ansible-vault: Manage secrets securely.
  • ansible-inventory: Work with inventories dynamically.
  • ansible-galaxy: Handle roles and collections for modular automation.
  • ansible-console: Experiment and debug interactively.

Different Ansible CLI Tools

ansible 
ansible-console     # REPL console for executing Ansible tasks (interactive prompt).
ansible-inventory   # View or manipulate inventory data (i.e., listing all hosts or their variables)
ansible-config      # View, list, or validate Anxible config files and settings
ansible-doc         # Plugin documentation tool. Displays module docs, inventory plugins, etc.
ansible-playbook    # Runs ansible playbooks.  
ansible-vault       # Encryption/decryption utility for Ansible data files
ansible-galaxy      # Manage roles and collections (install, list, remove, or create)
ansible-pull        # Pull and execute playbooks from remote SCM repositories (like Git)
ansible-connection  # Internal tool for managing remote connections (primarily for devs)
ansible-test        # Internal testing tool for validating changes to ansible itself (for contributors)

Requirements for Ansible

Control Node Requirements

Your "Control Node" (the machine running Ansible) can be any Linux/Unix
machine with Python 3.8 or newer installed.
* Your Control Node cannot be a Windows machine.

Managed Nodes Requirements

For the "Managed Nodes" (the machines being managed by Ansible), Ansible
needs to communicate with them over SSH and SFTP (can be switched to SCP in
the ansible.cfg file), or WinRM (Windows Remote Management) for Windows hosts.

The Managed Nodes also need Python 2.6 or later, or Python 3.5 or later.

For Windows nodes, you need PowerShell 3.0 or later, and at least .NET 4.0 installed.

So, to summarize, managed nodes need:
SSH/SFTP (or SCP) access to the Managed Nodes * Python 2.6 or later, or* Python 3.5 or later.

Or, managed nodes on windows: * WinRM access for Windows.
* PowerShell 3.0+ and .NET 4.0+ for Windows.