Ansible Variables, Handlers, and Templates

Understanding Variables

Variables make playbooks reusable across environments. They can be defined in playbooks, inventories, command-line arguments, and roles

Variable Example

---
- hosts: webservers

  vars:
    web_package: nginx

  tasks:
    - name: Install package
      apt:
        name: "{{ web_package }}"
        state: present

Handlers

Handlers run only when notified by a changed task.

Example:

tasks:
  - name: Update nginx config
    template:
      src: nginx.conf.j2
      dest: /etc/nginx/nginx.conf
    notify:
      - Restart Nginx

handlers:
  - name: Restart Nginx
    service:
      name: nginx
      state: restarted

Jinja2 Templates

Template file:

server {
    listen {{ nginx_port }};
}

Playbook:

vars:
  nginx_port: 8080

Variable Files

vars_files:
  - vars/common.yml

Example:

nginx_port: 8080
environment: production

Best Practices

• Use variables instead of hardcoded values.
• Keep secrets outside playbooks.
• Use templates for configuration files.
• Use handlers for service restarts