Ansible // TLDR

Basic Concepts

Playbooks: YAML files that define automation tasks.
Modules: Reusable units of automation that perform specific tasks.
Tasks: Instructions within a playbook that execute modules.
Hosts: The target systems to be managed.
Inventory: A file or directory that defines the hosts to be managed.

Playbook Structure

YAML

- name: My Playbook
  hosts: all
  tasks:
    - name: Install a package
      apt:
        name: httpd
        state: present

Common Modules

apt: Manage Debian/Ubuntu packages
yum: Manage RPM-based packages
service: Manage system services
user: Manage system users
file: Manage files and directories
template: Render templates from Jinja2 templates
script: Execute scripts on remote hosts
copy: Copy files to remote hosts
fetch: Fetch files from remote hosts

Ad-hoc Commands

Bash

ansible all -m ping
ansible webservers -m shell -a 'ls -la /var/www'
ansible dbservers -m user -a "name=dbuser state=present"

Variables

Inline:
YAML
```
vars:
  http_port: 80
```
Vars files:
YAML
```
vars_files:
  - vars/main.yml
```

Templates

YAML

- name: Configure a web server
  template:
    src: templates/httpd.conf.j2
    dest: /etc/httpd/conf/httpd.conf

Conditionals

YAML

- name: Install a package (conditional)
  apt:
    name: httpd
    state: present
  when: ansible_distribution == "Ubuntu"

Loops

YAML

- name: Create users
  user:
    name: "{{ item }}"
    state: present
  with_items:
    - user1
    - user2
    - user3

Handlers

YAML

handlers:
  - name: Restart Apache
    service:
      name: httpd
      state: restarted

tasks:
  - name: Update the configuration
    template:
      src: templates/httpd.conf.j2
      dest: /etc/httpd/conf/httpd.conf
    notify: Restart Apache

Roles

Organize playbooks into reusable units.
Structure: roles/role_name/tasks/main.yml, templates, handlers, etc.

Ansible-Vault

Encrypt sensitive data.
Use ansible-vault encrypt_file and ansible-vault decrypt_file.

Additional Tips

Use ansible-playbook -i inventory/production.yml -v my_playbook.yml for verbose output.
Leverage Ansible Galaxy to find and install roles.
Use Ansible Tower for centralized management and scheduling.
Write clear and concise playbooks.
Test your playbooks thoroughly.

Core Concepts:

Playbook: A YAML file that defines a series of tasks to be executed on one or more hosts.
Task: A specific action to be performed, such as installing a package, copying a file, or executing a command.
Module: Reusable pieces of code that perform specific tasks, like handling files, packages, services, and more.
Inventory: A list of hosts that Ansible can manage, often organized into groups.
Variable: A named value that can be used within playbooks and templates.
Template: A file that uses Jinja2 templating language to dynamically generate configuration files.

Additional Terms:

Control Node: The machine where Ansible is installed and executed.
Remote Node: The target machine(s) that Ansible manages.
SSH: The protocol used to securely connect to remote nodes.
Handlers: Tasks that are triggered by changes made by other tasks.
Roles: A way to organize playbooks into reusable units, often based on functionality.
Ansible Galaxy: A repository of shared Ansible roles and modules.

For more in-depth information, refer to the official Ansible documentation: https://docs.ansible.com/