Ansible Cheatsheet

Ad-Hoc Commands

Ad-hoc commands execute a single task quickly using ansible -m -a "".

### Connectivity Test

``yaml # Test connectivity of all hosts (ping module) ansible all -m ping `

### Execute Commands

`yaml # Run a shell command on the webservers group ansible webservers -m shell -a "uptime"

# Run a command module (no pipes/redirects) ansible webservers -m command -a "whoami" `

### File Operations

`yaml # Copy a local file to remote hosts ansible all -m copy -a "src=/etc/hosts dest=/tmp/hosts owner=root group=root mode=0644"

# Manage file attributes (create/delete/permissions) ansible all -m file -a "path=/app/data state=directory mode=0755"

# Delete a file ansible all -m file -a "path=/tmp/old.log state=absent" `

### Package Management

`yaml # Debian/Ubuntu install package ansible all -m apt -a "name=nginx state=present" -b

# RHEL/CentOS install package ansible all -m yum -a "name=httpd state=latest" -b `

### Service Management

`yaml # Start and enable a service ansible all -m service -a "name=nginx state=started enabled=yes" -b

# Use systemd module ansible all -m systemd -a "name=nginx state=restarted daemon_reload=yes" -b `

Inventory Management

The inventory defines target hosts and groups in INI or YAML format.

### Basic Inventory (INI Format)

`yaml # /etc/ansible/hosts # [webservers] # web1 ansible_host=192.168.1.10 # web2 ansible_host=192.168.1.11 # # [dbservers] # db1 ansible_host=192.168.1.20 # # [all:vars] # ansible_user=deploy # ansible_port=22

# View inventory ansible-inventory --list

# Use a custom inventory file ansible all -i inventory.ini -m ping

# Limit targets to a single host ansible-playbook site.yml --limit web1 `

### Dynamic Inventory

`yaml # Use AWS EC2 dynamic inventory ansible-inventory -i aws_ec2.yaml --graph

# List all hosts in inventory ansible all -i aws_ec2.yaml --list-hosts `

Modules

Ansible ships with thousands of built-in modules. Below are common examples.

### Template and Configuration

`yaml # Render a Jinja2 template - name: Configure nginx virtual host ansible.builtin.template: src: nginx.conf.j2 dest: /etc/nginx/sites-available/default owner: root group: root mode: "0644" notify: restart nginx `

### Network and Downloads

`yaml # Download a file ansible all -m get_url -a "url=https://example.com/file.tar.gz dest=/tmp/file.tar.gz checksum=sha256:abc123"

# Extract an archive ansible all -m unarchive -a "src=/tmp/file.tar.gz dest=/opt/app remote_src=yes creates=/opt/app/bin" `

### Git Operations

`yaml # Clone a Git repository ansible all -m git -a "repo=https://github.com/example/app.git dest=/opt/app version=main force=yes" `

### Docker Containers

`yaml # Manage a Docker container ansible all -m docker_container -a "name=myapp image=nginx:alpine state=started ports=80:80 restart_policy=always" `

Playbook Writing

Playbooks are the heart of Ansible automation, written in YAML.

### Basic Playbook Structure

`yaml --- - name: Deploy Web Application hosts: webservers become: yes vars: app_port: 8080 tasks: - name: Ensure Nginx is installed apt: name: nginx state: present

- name: Deploy configuration file template: src: app.conf.j2 dest: /etc/nginx/conf.d/app.conf notify: restart nginx

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

handlers: - name: restart nginx service: name: nginx state: restarted `

### Conditions and Loops

`yaml # Conditional execution (when) - name: Run only on Debian systems apt: name: python3 state: present when: ansible_os_family == "Debian"

# Simple loop - name: Create multiple users user: name: "{{ item }}" state: present groups: sudo loop: - alice - bob - charlie

# Dictionary loop - name: Configure multiple service ports firewalld: service: "{{ item.key }}" port: "{{ item.value }}" permanent: yes state: enabled loop: "{{ services | dict2items }}" vars: services: http: 80 https: 443 `

### Includes and Imports

`yaml # Include tasks from another file - name: Include common setup tasks include_tasks: tasks/common_setup.yml

# Use roles - name: Apply nginx role hosts: webservers roles: - role: nginx nginx_port: 8080 - role: geerlingguy.security `

Variables and Templates

### Variable Definition and Usage

`yaml # Define variables in a playbook vars: domain: example.com ssl_cert_path: /etc/ssl/certs/{{ domain }}.pem

# Interactive variable prompts - name: Prompt for variables hosts: all vars_prompt: - name: admin_password prompt: "Enter admin password" private: yes confirm: yes - name: deploy_version prompt: "Deployment version" default: "1.0.0" `

### Registering Variables and Debugging

`yaml # Register task output - name: Check disk space shell: df -h / register: disk_output

# Debug output - name: Show disk information debug: msg: "Disk usage: {{ disk_output.stdout }}"

# Debug variables - name: Print all host variables debug: var: hostvars[inventory_hostname]

# Conditional based on registered variable - name: Alert on low disk space fail: msg: "Disk usage exceeds 90%" when: "'90%' in disk_output.stdout" `

Advanced Features

### Tags

`yaml # Tag tasks for selective execution tasks: - name: Install base packages apt: name: "{{ item }}" loop: - curl - vim - git tags: - packages - base

- name: Configure firewall ufw: rule: allow port: "22,80,443" tags: - firewall - security

# Run specific tags # ansible-playbook site.yml --tags security

# Skip specific tags # ansible-playbook site.yml --skip-tags firewall `

### Vault (Encryption)

`yaml # Encrypt sensitive files # ansible-vault encrypt secrets.yml

# Use encrypted variables # vars_files: # - secrets.yml

# Decrypt during playbook run # ansible-playbook site.yml --ask-vault-pass `

### Common Playbook Options

`yaml # Check mode (dry run, no changes) # ansible-playbook site.yml --check

# Show diff of changes # ansible-playbook site.yml --diff

# Verbose output # ansible-playbook site.yml -vvv

# Specify SSH user # ansible-playbook site.yml -u deploy

# Specify private key # ansible-playbook site.yml --private-key ~/.ssh/deploy_key

# Serial execution (one host at a time) # ansible-playbook site.yml --forks 1

# Syntax check only # ansible-playbook site.yml --syntax-check ``