Ansible Installation Guide

Ansible is an open-source automation tool that enables infrastructure as code, configuration management, application deployment, and task automation. It uses a simple, human-readable language (YAML) and requires no agents on remote systems.

Prerequisites

• Python 2.7 or Python 3.5+ (Python 3.9+ recommended)
• Control node: Linux/Unix/macOS (Windows is not supported as a control node)
• Managed nodes: Windows or Unix/Linux systems
• SSH access to managed nodes
• Administrative/sudo privileges

Installation Instructions

# Update package index
sudo apt update
 
# Install dependencies
sudo apt install -y python3 python3-pip
 
# Install Ansible
sudo apt install -y ansible
 
# Alternative: Install via pip
pip3 install --user ansible

Basic Configuration

1. Create Configuration Directory

# Create Ansible directory structure
mkdir -p ~/ansible/playbooks
cd ~/ansible

2. Configure Inventory

Create inventory.ini:

[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=your_ssh_user
ansible_ssh_private_key_file=~/.ssh/id_rsa

3. Configure Ansible

Create ansible.cfg:

[defaults]
inventory = ./inventory.ini
remote_user = your_ssh_user
private_key_file = ~/.ssh/id_rsa
host_key_checking = False

Basic Usage

1. Test Connection

# Ping all hosts
ansible all -m ping
 
# Check specific group
ansible webservers -m ping

2. Create First Playbook

Create playbooks/update_servers.yml:

---
- name: Update all servers
  hosts: all
  become: yes
  tasks:
    - name: Update apt cache (Debian/Ubuntu)
      apt:
        update_cache: yes
      when: ansible_os_family == "Debian"
 
    - name: Update dnf cache (RHEL/CentOS)
      dnf:
        update_cache: yes
      when: ansible_os_family == "RedHat"

3. Run Playbook

# Run playbook
ansible-playbook playbooks/update_servers.yml
 
# Run with extra variables
ansible-playbook playbooks/update_servers.yml -e "variable=value"

Advanced Configuration

1. SSH Key Setup

# Generate SSH key
ssh-keygen -t rsa -b 4096
 
# Copy key to remote hosts
ssh-copy-id username@remote_host

2. Vault Configuration

# Create encrypted file
ansible-vault create secrets.yml
 
# Edit encrypted file
ansible-vault edit secrets.yml
 
# Run playbook with vault
ansible-playbook playbook.yml --ask-vault-pass

3. Role Structure

# Create role structure
ansible-galaxy init my_role
 
# Role directory structure
my_role/
├── defaults/
├── files/
├── handlers/
├── meta/
├── tasks/
├── templates/
└── vars/

Best Practices

1. Project Organization

   • Use roles for reusable components
   • Keep sensitive data in Ansible Vault
   • Use version control for playbooks

2. Security

   • Use SSH keys instead of passwords
   • Implement proper inventory grouping
   • Secure sensitive variables

3. Performance

   • Use dynamic inventory when possible
   • Implement proper error handling
   • Use async tasks for long-running operations

Troubleshooting

Common Issues

1. SSH Connection Problems

   # Check SSH connection
   ssh -v username@remote_host
    
   # Test Ansible connection
   ansible host -m ping -vvv

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2. Permission Issues

   # Check sudo access
   ansible host -m shell -a "sudo -l"
    
   # Run with become
   ansible-playbook playbook.yml --become

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3. Python Issues

   # Check Python version
   ansible host -m setup -a "filter=ansible_python_version"
    
   # Install Python if missing
   ansible host -m raw -a "apt-get install -y python3"

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Error Resolution

1. Module Errors

   • Check module documentation
   • Verify module dependencies
   • Use correct module parameters

2. Playbook Syntax

   # Check playbook syntax
   ansible-playbook --syntax-check playbook.yml
    
   # Run in check mode
   ansible-playbook --check playbook.yml

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Additional Resources

• Official Ansible Documentation
• Ansible Galaxy
• Ansible Best Practices
• Ansible Examples