10 Essential Ansible Examples for System Administrators

In the fast-paced world of IT, system administrators are constantly seeking efficient and automated ways to manage and configure servers. Ansible, an open-source automation tool, has emerged as a powerful solution for streamlining these tasks. In this article, we'll explore ten essential Ansible examples that every system administrator should have in their toolkit. Whether you're a seasoned Ansible user or just getting started, these examples will help you automate common administrative tasks and save valuable time.

1. Installing Packages:

One of the fundamental tasks for system administrators is installing packages on servers. Ansible simplifies this process by allowing you to define the desired state and then applying it across multiple servers simultaneously.

---
- name: Install Nginx
  hosts: web_servers
  become: yes
  tasks:
    - name: Install Nginx
      apt:
        name: nginx
        state: present

In this example, Ansible is instructed to install the Nginx package on a group of servers defined as "web_servers."

2. Managing Services:

Controlling services is another crucial aspect of system administration. Ansible makes it easy to start, stop, or restart services on multiple servers with a simple playbook.

---
- name: Restart Apache
  hosts: app_servers
  become: yes
  tasks:
    - name: Restart Apache
      service:
        name: apache2
        state: restarted

Here, Ansible restarts the Apache service on the servers specified in the "app_servers" group.

3. Configuring Files:

System configuration often involves updating configuration files. Ansible allows you to manage these files efficiently by specifying the desired content and applying changes across servers.

---
- name: Configure SSH
  hosts: all
  become: yes
  tasks:
    - name: Update SSHd_config
      lineinfile:
        path: /etc/ssh/sshd_config
        regexp: '^PermitRootLogin'
        line: 'PermitRootLogin no'

This playbook disables root login via SSH by modifying the "sshd_config" file.

4. User Management:

Creating and managing user accounts is a common task for system administrators. Ansible provides a simple way to automate user management tasks across multiple servers.

---
- name: Add User
  hosts: all
  become: yes
  tasks:
    - name: Create User
      user:
        name: john_doe
        password: $6$rounds=10000$random_salt$encrypted_password

In this example, Ansible creates a user named "john_doe" with a securely encrypted password.

5. System Updates:

Keeping servers up-to-date is crucial for security and performance. Ansible facilitates the automation of system updates across multiple servers.

---
- name: Update System
  hosts: all
  become: yes
  tasks:
    - name: Update Packages
      apt:
        upgrade: dist

This playbook ensures that all packages on the specified servers are upgraded to the latest available version.

6. Managing Firewalls:

Securing servers often involves configuring firewalls. Ansible simplifies firewall management by providing modules to define rules across servers.

---
- name: Configure Firewall
  hosts: db_servers
  become: yes
  tasks:
    - name: Allow SSH
      ufw:
        rule: allow
        name: ssh

In this example, Ansible allows SSH traffic on servers designated as "db_servers" using the Uncomplicated Firewall (UFW) module.

7. Handling Cron Jobs:

Automating recurring tasks with cron jobs is a common practice. Ansible allows you to manage cron jobs easily across multiple servers.

---
- name: Schedule Backup
  hosts: backup_servers
  become: yes
  tasks:
    - name: Add Cron Job
      cron:
        name: "Backup Task"
        minute: "0"
        hour: "2"
        job: "/path/to/backup_script.sh"

This playbook adds a cron job on servers specified in the "backup_servers" group, scheduling a backup task to run daily at 2:00 AM.

8. Docker Management:

Managing containers with Docker is prevalent in modern IT environments. Ansible facilitates the orchestration of Docker containers across servers.

---
- name: Start Docker Container
  hosts: docker_servers
  become: yes
  tasks:
    - name: Run Nginx Container
      docker_container:
        name: nginx_container
        image: nginx
        state: started

This example starts an Nginx container on servers defined as "docker_servers."

9. Dynamic Inventories:

Ansible supports dynamic inventories, allowing you to manage servers dynamically. This is particularly useful in cloud environments.

---
- name: Dynamic Inventory Example
  hosts: tag_environment_production
  become: yes
  tasks:
    - name: Install Application
      apt:
        name: my_application
        state: present

Here, Ansible targets servers with the tag "environment=production" dynamically.

10. Role-based Playbooks:

Organizing Ansible playbooks into roles enhances modularity and maintainability. This example demonstrates how to structure playbooks using roles.

---
- name: Role-based Playbook
  hosts: web_servers
  become: yes
  roles:
    - common
    - web_server

In this playbook, Ansible applies the "common" and "web_server" roles to the servers in the "web_servers" group.