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Developer notes

Ansible Playbook Techniques

Storage and Device Management

  • How to format and mount a block device (and only if a variable is defined): 250-mount-longhorn.yaml 
    # Example snippet:
- name: Format the device
  filesystem:
    fstype: ext4
    dev: "{{ longhorn_device }}"
  when: longhorn_device is defined

User Interaction

  • How to ask "are you sure you want to continue etc": 399-uninstall.yaml 
    # Example snippet:
- name: Confirm uninstallation
  pause:
    prompt: "Are you sure you want to uninstall RKE2 from all nodes? This will DELETE ALL YOUR DATA. Type 'yes' to continue"
  register: confirmation
  failed_when: confirmation.user_input != "yes"

Host Selection and Delegation

  • How to get the name of the first host from a group: 332-more-controllers.yaml, 342-workers.yaml at delegate_to 
    # Example snippet:
- name: Copy kubeconfig from first controller
  delegate_to: "{{ groups['controllers'][0] }}"
  # Task details...

Execution Control

  • Run tasks one by one: 330-more-controllers.yaml at serial 
    # Example snippet:
- hosts: controllers[1:]
  serial: 1
  # Task details...

Common Development Patterns

Conditional Execution

  • Using tags to selectively run parts of playbooks
  • Using variables to enable/disable features

Error Handling

  • Using ignore_errors and failed_when for graceful failure handling
  • Using register and checking results for conditional execution

Security Best Practices

  • Using no_log: true for sensitive information
  • Managing secrets with Vault integration

Troubleshooting

Common Issues

  • RKE2 installation failures: Check system requirements and network connectivity
  • Certificate issues: Verify DNS resolution and firewall settings
  • Storage problems: Check device permissions and filesystem status

Debugging Techniques

  • Using ansible -vvv for verbose output
  • Checking logs on target hosts
  • Using kubectl describe for detailed resource information

Contributing Guidelines

Code Style

  • Follow consistent YAML formatting
  • Use descriptive variable names
  • Include comments for complex operations

Testing

  • Test playbooks in a development environment before submitting
  • Verify idempotence (playbooks can be run multiple times without errors)
  • Test with different OS versions when applicable

Documentation

  • Update relevant documentation when adding new features
  • Include examples for new functionality
  • Document any new variables or dependencies