Ansible

Description:

• Configuration management

• Agentless: dont have to install anything on the target system, use SSH

  • except Python

• Use cases:

  • Eliminate repetition and simplify workflows
  • Manage and maintain system configuration
  • Continuously deploy complex software
  • Perform zero-downtime rolling updates

• 

• 1 control node and many managemed nodes

  • managed node: run the instruction sent from control

• Ansible Inventory:

  • contain informatin about the managed nodes
    • in .init or .yaml
  • nodes can be grouped into groups, groups can be grouped into meta group
  • host variables ar defined as key-value pairs

• Idempotency:

  • Idempotency means one action executing once or many times yield the same result
  • Most ansible modules are idempotent
  • Module idempotency is the key component for Ansible to implement the declarative approach of IaC

Google Namespace in Ansible

Getting started:

Basic:

Installation:

• pip install ansible

Concepts:

• Control node
  • run ansible commands
  • sends tasks to managed node via SSH
  • Node infor is stored in the inventory file
• Managed node
  • must have a file to list all the ip or FQDN of host
• Ansible Inventory
• Ansible Playbook
• Ansible Module
• Ansible Plugin
• Ansible Collection

Installation:

Using Ansible:

Building Inventories

s

Commands:

• ansible - Define and run a single task ‘playbook’ against a set of hosts.
• ansible-config - View ansible configuration.
• ansible-console - REPL console for executing Ansible tasks.
• ansible-doc - Plugin documentation tool.
• ansible-galaxy - Collection and role operations
• ansible-inventory - Show inventory informations
• ansible-playbook - Runs Ansible playbooks, executing the defined tasks on the targeted hosts.
• ansible-pull - Pulls playbooks from a VCS repo and executes them for the local host
• ansible-vault - Encryption/decryption utility for Ansible data files