Add metalctl CLI with move Command to Migrate CRDs and CRs Between Clusters

[afritzler]

Description

We are introducing a new CLI tool called metalctl to interact with the metal-operator as part of our metal-operator ecosystem. The initial command to be implemented is the move command, which will facilitate the migration of Custom Resource Definitions (CRDs) and Custom Resources (CRs) related to metal-operator from one Kubernetes cluster to another.

Goal

• Create a new CLI utility called metalctl.
• Integrate the move command to migrate all metal-operator related CRDs and CRs between two clusters.

Key Objectives

• Ensure seamless migration of metal-operator CRDs and CRs.
• Ensure the migration process handles dependency order (CRDs must be moved present before CRs).
• Handle failure scenarios gracefully with appropriate error messages and rollback functionality.

Command Details

Command: move

The move command will enable users to specify a source and target Kubernetes cluster for migrating CRDs and CRs associated with the metal-operator.

Command Options:

• --source-kubeconfig (required): Path to the kubeconfig of the source cluster.
• --target-kubeconfig (required): Path to the kubeconfig of the target cluster.
  - --crds-only (optional): Flag to migrate only the CRDs without CRs.
  - --crs-only (optional): Flag to migrate only the CRs without CRDs.
• --namespace (optional): Specify a namespace to filter CRDs and CRs to migrate. Defaults to all namespaces if not specified.
• --dry-run (optional): Perform a dry run to show what would be moved without executing the migration.
• --verbose (optional): Enable verbose logging for detailed output during migration.

Example Usage:

metalctl move --source-kubeconfig=~/.kube/source-cluster.yaml \
              --target-kubeconfig=~/.kube/target-cluster.yaml \
              --namespace=metal-namespace

Steps in the move Process:

1. Validate Input: Verify the presence of both source-kubeconfig and target-kubeconfig.
2. Fetch CRDs from Source Cluster: Use the source kubeconfig to list all CRDs related to the metal-operator.
3. Apply CRDs to Target Cluster: Use the target kubeconfig to apply the CRDs. Ensure idempotency in case they already exist.
4. Fetch CRs from Source Cluster: Fetch all CRs of the metal-operator from the source cluster.
5. Apply CRs to Target Cluster: Apply all CRs to the target cluster.
6. Verify Migration: Ensure the CRDs and CRs have been successfully created in the target cluster.
7. Error Handling and Rollback: If any step fails, provide detailed error messages and rollback any partial migrations where applicable.

Definition of Done

• A new CLI tool metalctl is created with a functional move command.
• The move command successfully migrates metal-operator CRDs and CRs between clusters.
• Support for dry-run, crds-only, crs-only, and namespace options.
• Detailed documentation for using the move command is included.
• Adequate test coverage for the move functionality, including unit tests and integration tests.

Additional Considerations

• Future commands for metalctl can include operations like listing or deleting resources, which should be planned for in the CLI structure.
• Console access: Add a console command to access the serial console of a server. This will allow users to remotely view or interact with a server's console for debugging and management purposes.

[afritzler]

@hardikdr we might need something like that in the boot-operator project as well.

[SchwarzM]

please use : https://github.com/spf13/cobra as scaffold for the cli as well as a configurable structured logging facility