Getting Started with Ansible for Server Management

What is Ansible?

Ansible automates server configuration, application deployment, and task orchestration. It connects via SSH — no agent needed on target servers.

Installation

# On your control machine (local or CI server)
pip install ansible

# Or via apt
sudo apt install -y ansible

Inventory

Define your servers:

# inventory/hosts
[web]
web1 ansible_host=198.51.100.10
web2 ansible_host=198.51.100.11

[db]
db1 ansible_host=198.51.100.20

[all:vars]
ansible_user=deploy
ansible_python_interpreter=/usr/bin/python3

Ad-Hoc Commands

# Ping all servers
ansible all -i inventory/hosts -m ping

# Check uptime
ansible web -i inventory/hosts -a "uptime"

# Install a package
ansible web -i inventory/hosts -m apt -a "name=nginx state=present" --become

Playbooks

# playbooks/setup-web.yml
---
- name: Configure web servers
  hosts: web
  become: yes
  vars:
    domain: example.com

  tasks:
    - name: Update apt cache
      apt:
        update_cache: yes
        cache_valid_time: 3600

    - name: Install packages
      apt:
        name:
          - nginx
          - php8.3-fpm
          - php8.3-mysql
          - certbot
        state: present

    - name: Copy Nginx config
      template:
        src: templates/nginx.conf.j2
        dest: /etc/nginx/sites-available/{{ domain }}.conf
      notify: Reload Nginx

    - name: Enable site
      file:
        src: /etc/nginx/sites-available/{{ domain }}.conf
        dest: /etc/nginx/sites-enabled/{{ domain }}.conf
        state: link
      notify: Reload Nginx

    - name: Ensure Nginx is running
      service:
        name: nginx
        state: started
        enabled: yes

  handlers:
    - name: Reload Nginx
      service:
        name: nginx
        state: reloaded

# Run the playbook
ansible-playbook -i inventory/hosts playbooks/setup-web.yml

Roles

Organize reusable configurations:

roles/
├── common/
│   └── tasks/main.yml      # Base packages, users, SSH
├── nginx/
│   ├── tasks/main.yml       # Install and configure
│   ├── templates/nginx.conf.j2
│   └── handlers/main.yml
└── mysql/
    ├── tasks/main.yml
    └── templates/my.cnf.j2

# playbooks/site.yml
- hosts: web
  roles:
    - common
    - nginx

Idempotency

Ansible tasks are idempotent — running them twice produces the same result:

# This only installs if nginx is not already present
- name: Install Nginx
  apt:
    name: nginx
    state: present

Tip Start with ad-hoc commands to learn, then graduate to playbooks. Don't jump to roles until you have 3+ playbooks with shared tasks.