fix(vm): fix live migration with image hotplug (#1041)

fix live migration with image hotplug
---------
Signed-off-by: Yaroslav Borbat <yaroslav.borbat@flant.com>
Co-authored-by: Ivan Mikheykin <ivan.mikheykin@flant.com>

Author: yaroslavborbat

images/virtualization-artifact/pkg/controller/livemigration/live_migration_reconciler.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 
+	"k8s.io/apimachinery/pkg/types"
 	virtv1 "kubevirt.io/api/core/v1"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
@@ -88,15 +89,23 @@ func (r *Reconciler) Reconcile(ctx context.Context, req reconcile.Request) (reco
 		return h.Handle(ctx, kvvmi.Changed())
 	})
 	rec.SetResourceUpdater(func(ctx context.Context) error {
-		if livemigration.IsMigrationConfigurationChanged(kvvmi.Current(), kvvmi.Changed()) {
-			// Directly update kvvmi and not use kvvmi.Update as kvvmi status is a regular field, not a subresource.
+
+		patchBytes, err := livemigration.GenerateMigrationConfigurationPatch(kvvmi.Current(), kvvmi.Changed())
+		if err != nil {
+			return err
+		}
+
+		if patchBytes != nil {
 			log.Debug("About to update changed kvvmi",
 				"changed.migration.configuration", livemigration.DumpKVVMIMigrationConfiguration(kvvmi.Changed()),
 				"current.migration.configuration", livemigration.DumpKVVMIMigrationConfiguration(kvvmi.Current()),
 			)
-			if err := r.client.Update(ctx, kvvmi.Changed()); err != nil {
-				return fmt.Errorf("error updating status subresource: %w", err)
+
+			jsonPatch := client.RawPatch(types.JSONPatchType, patchBytes)
+			if err := r.client.Patch(ctx, kvvmi.Current(), jsonPatch); err != nil {
+				return fmt.Errorf("error patching status field: %w", err)
 			}
+
 			return nil
 		}
 

images/virtualization-artifact/pkg/livemigration/migration_configuration.go

@@ -19,10 +19,12 @@ package livemigration
 import (
 	"encoding/json"
 	"fmt"
-	"reflect"
 
+	"k8s.io/apimachinery/pkg/api/equality"
 	"k8s.io/apimachinery/pkg/api/resource"
 	virtv1 "kubevirt.io/api/core/v1"
+
+	"github.com/deckhouse/virtualization-controller/pkg/common/patch"
 )
 
 // Live migration defaults from kubevirt
@@ -93,22 +95,21 @@ func DumpKVVMIMigrationConfiguration(kvvmi *virtv1.VirtualMachineInstance) strin
 	return string(out)
 }
 
-// IsMigrationConfigurationChanged detects if MigrationConfiguration was changed.
-func IsMigrationConfigurationChanged(current, changed *virtv1.VirtualMachineInstance) bool {
-	// true if migrationConfiguration was added.
-	if current.Status.MigrationState != nil && current.Status.MigrationState.MigrationConfiguration == nil &&
-		changed.Status.MigrationState != nil && changed.Status.MigrationState.MigrationConfiguration != nil {
-		return true
+func GenerateMigrationConfigurationPatch(current, changed *virtv1.VirtualMachineInstance) ([]byte, error) {
+	if current.Status.MigrationState == nil || changed.Status.MigrationState == nil {
+		return nil, nil
+	}
+	currentConf := current.Status.MigrationState.MigrationConfiguration
+	changedConf := changed.Status.MigrationState.MigrationConfiguration
+
+	if equality.Semantic.DeepEqual(currentConf, changedConf) {
+		return nil, nil
 	}
 
-	// Compare MigrationConfiguration. Handler may change options.
-	if current.Status.MigrationState != nil && current.Status.MigrationState.MigrationConfiguration != nil &&
-		changed.Status.MigrationState != nil && changed.Status.MigrationState.MigrationConfiguration != nil {
-		return !reflect.DeepEqual(
-			current.Status.MigrationState.MigrationConfiguration,
-			changed.Status.MigrationState.MigrationConfiguration,
-		)
+	op := patch.PatchReplaceOp
+	if currentConf == nil {
+		op = patch.PatchAddOp
 	}
 
-	return false
+	return patch.NewJsonPatch(patch.NewJsonPatchOperation(op, "/status/migrationState/migrationConfiguration", changedConf)).Bytes()
 }