Ansible Playbook for Server Configuration

Create Ansible playbooks for configuring and managing servers.

Target servers:
- OS: [Ubuntu/CentOS/Amazon Linux]
- Count: [number of servers]
- Roles: [web server/app server/database/all-in-one]
- Cloud provider: [AWS/GCP/Azure/on-premise]

Configuration requirements:
1. Base system hardening
2. User management and SSH keys
3. Package installation and updates
4. Firewall configuration (iptables/firewalld)
5. Service configuration (nginx, application services)
6. SSL certificate management
7. Log rotation
8. Monitoring agent installation
9. Backup configuration

Please include:
- Inventory file structure
- Role-based playbook organization
- Variable files for different environments
- Handlers for service restarts
- Vault for sensitive data
- Idempotent task design