feat(kubevirt): add VM lifecycle management tools (start, stop, restart) (#533)

* feat(kubevirt): add VM lifecycle tools into single vm_lifecycle tool

Add the vm_start, vm_stop, and vm_restart tools into a
single vm_lifecycle tool with an 'action' parameter.

The new vm_lifecycle tool accepts:
- namespace: The namespace of the virtual machine
- name: The name of the virtual machine
- action: The lifecycle action ('start', 'stop', or 'restart')

- start: changes runStrategy to Always
- stop: changes runStrategy to Halted
- restart: stops then starts the VM

Code was assisted by Cursor AI.

Signed-off-by: Karel Simon <[email protected]>

* test(kubevirt): add tests for vm_lifecycle tool

Add tests for the vm_lifecycle tool

Code was assisted by Cursor AI.

Signed-off-by: Karel Simon <[email protected]>

* feat: adjust README.md file

Code was assisted by Cursor AI.

Signed-off-by: Karel Simon <[email protected]>

* feat: change idempotent and desctructive hint

The destructive hint is changed to true, since restart might cause
unexpected troubles inside VM.
Idempotent hint is changed to false, because the restart action
might cause additional effects on rest of the workload.

Signed-off-by: Karel Simon <[email protected]>

---------

Signed-off-by: Karel Simon <[email protected]>

Author: ksimon1

README.md

@@ -521,6 +521,11 @@ In case multi-cluster support is enabled (default) and you have access to multip
   - `storage` (`string`) - Optional storage size for the VM's root disk when using DataSources (e.g., '30Gi', '50Gi', '100Gi'). Defaults to 30Gi. Ignored when using container disks.
   - `workload` (`string`) - The workload for the VM. Accepts OS names (e.g., 'fedora' (default), 'ubuntu', 'centos', 'centos-stream', 'debian', 'rhel', 'opensuse', 'opensuse-tumbleweed', 'opensuse-leap') or full container disk image URLs
 
+- **vm_lifecycle** - Manage VirtualMachine lifecycle: start, stop, or restart a VM
+  - `action` (`string`) **(required)** - The lifecycle action to perform: 'start' (changes runStrategy to Always), 'stop' (changes runStrategy to Halted), or 'restart' (stops then starts the VM)
+  - `name` (`string`) **(required)** - The name of the virtual machine
+  - `namespace` (`string`) **(required)** - The namespace of the virtual machine
+
 </details>
 
 

pkg/kubevirt/vm.go

@@ -0,0 +1,160 @@
+package kubevirt
+
+import (
+	"context"
+	"fmt"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/dynamic"
+)
+
+// RunStrategy represents the run strategy for a VirtualMachine
+type RunStrategy string
+
+const (
+	RunStrategyAlways RunStrategy = "Always"
+	RunStrategyHalted RunStrategy = "Halted"
+)
+
+var (
+	// VirtualMachineGVK is the GroupVersionKind for VirtualMachine resources
+	VirtualMachineGVK = schema.GroupVersionKind{
+		Group:   "kubevirt.io",
+		Version: "v1",
+		Kind:    "VirtualMachine",
+	}
+
+	// VirtualMachineGVR is the GroupVersionResource for VirtualMachine resources
+	VirtualMachineGVR = schema.GroupVersionResource{
+		Group:    "kubevirt.io",
+		Version:  "v1",
+		Resource: "virtualmachines",
+	}
+)
+
+// GetVirtualMachine retrieves a VirtualMachine by namespace and name
+func GetVirtualMachine(ctx context.Context, client dynamic.Interface, namespace, name string) (*unstructured.Unstructured, error) {
+	return client.Resource(VirtualMachineGVR).Namespace(namespace).Get(ctx, name, metav1.GetOptions{})
+}
+
+// GetVMRunStrategy retrieves the current runStrategy from a VirtualMachine
+// Returns the strategy, whether it was found, and any error
+func GetVMRunStrategy(vm *unstructured.Unstructured) (RunStrategy, bool, error) {
+	strategy, found, err := unstructured.NestedString(vm.Object, "spec", "runStrategy")
+	if err != nil {
+		return "", false, fmt.Errorf("failed to read runStrategy: %w", err)
+	}
+
+	return RunStrategy(strategy), found, nil
+}
+
+// SetVMRunStrategy sets the runStrategy on a VirtualMachine
+func SetVMRunStrategy(vm *unstructured.Unstructured, strategy RunStrategy) error {
+	return unstructured.SetNestedField(vm.Object, string(strategy), "spec", "runStrategy")
+}
+
+// UpdateVirtualMachine updates a VirtualMachine in the cluster
+func UpdateVirtualMachine(ctx context.Context, client dynamic.Interface, vm *unstructured.Unstructured) (*unstructured.Unstructured, error) {
+	return client.Resource(VirtualMachineGVR).
+		Namespace(vm.GetNamespace()).
+		Update(ctx, vm, metav1.UpdateOptions{})
+}
+
+// StartVM starts a VirtualMachine by updating its runStrategy to Always
+// Returns the updated VM and true if the VM was started, false if it was already running
+func StartVM(ctx context.Context, dynamicClient dynamic.Interface, namespace, name string) (*unstructured.Unstructured, bool, error) {
+	// Get the current VirtualMachine
+	vm, err := GetVirtualMachine(ctx, dynamicClient, namespace, name)
+	if err != nil {
+		return nil, false, fmt.Errorf("failed to get VirtualMachine: %w", err)
+	}
+
+	currentStrategy, found, err := GetVMRunStrategy(vm)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Check if already running
+	if found && currentStrategy == RunStrategyAlways {
+		return vm, false, nil
+	}
+
+	// Update runStrategy to Always
+	if err := SetVMRunStrategy(vm, RunStrategyAlways); err != nil {
+		return nil, false, fmt.Errorf("failed to set runStrategy: %w", err)
+	}
+
+	// Update the VM in the cluster
+	updatedVM, err := UpdateVirtualMachine(ctx, dynamicClient, vm)
+	if err != nil {
+		return nil, false, fmt.Errorf("failed to start VirtualMachine: %w", err)
+	}
+
+	return updatedVM, true, nil
+}
+
+// StopVM stops a VirtualMachine by updating its runStrategy to Halted
+// Returns the updated VM and true if the VM was stopped, false if it was already stopped
+func StopVM(ctx context.Context, dynamicClient dynamic.Interface, namespace, name string) (*unstructured.Unstructured, bool, error) {
+	// Get the current VirtualMachine
+	vm, err := GetVirtualMachine(ctx, dynamicClient, namespace, name)
+	if err != nil {
+		return nil, false, fmt.Errorf("failed to get VirtualMachine: %w", err)
+	}
+
+	currentStrategy, found, err := GetVMRunStrategy(vm)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Check if already stopped
+	if found && currentStrategy == RunStrategyHalted {
+		return vm, false, nil
+	}
+
+	// Update runStrategy to Halted
+	if err := SetVMRunStrategy(vm, RunStrategyHalted); err != nil {
+		return nil, false, fmt.Errorf("failed to set runStrategy: %w", err)
+	}
+
+	// Update the VM in the cluster
+	updatedVM, err := UpdateVirtualMachine(ctx, dynamicClient, vm)
+	if err != nil {
+		return nil, false, fmt.Errorf("failed to stop VirtualMachine: %w", err)
+	}
+
+	return updatedVM, true, nil
+}
+
+// RestartVM restarts a VirtualMachine by temporarily setting runStrategy to Halted then back to Always
+func RestartVM(ctx context.Context, dynamicClient dynamic.Interface, namespace, name string) (*unstructured.Unstructured, error) {
+	// Get the current VirtualMachine
+	vm, err := GetVirtualMachine(ctx, dynamicClient, namespace, name)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get VirtualMachine: %w", err)
+	}
+
+	// Stop the VM first
+	if err := SetVMRunStrategy(vm, RunStrategyHalted); err != nil {
+		return nil, fmt.Errorf("failed to set runStrategy to Halted: %w", err)
+	}
+
+	vm, err = UpdateVirtualMachine(ctx, dynamicClient, vm)
+	if err != nil {
+		return nil, fmt.Errorf("failed to stop VirtualMachine: %w", err)
+	}
+
+	// Start the VM again
+	if err := SetVMRunStrategy(vm, RunStrategyAlways); err != nil {
+		return nil, fmt.Errorf("failed to set runStrategy to Always: %w", err)
+	}
+
+	updatedVM, err := UpdateVirtualMachine(ctx, dynamicClient, vm)
+	if err != nil {
+		return nil, fmt.Errorf("failed to start VirtualMachine: %w", err)
+	}
+
+	return updatedVM, nil
+}