Handle rollback of Kata deployment based on featuregate

This commit handles changes to the deployment method
from extension to image or vice-versa.

Fixes: #KATA-2902

Signed-off-by: Pradipta Banerjee <pradipta.banerjee@gmail.com>

controllers/mc_handler.go

@@ -24,6 +24,11 @@ const (
 	image_mc_name     = "50-enable-sandboxed-containers-image"
 )
 
+type DeploymentState struct {
+	PreviousMethod string
+	PreviousMcName string
+}
+
 // If the first return value is 'true' it means that the MC was just created
 // by this call, 'false' means that it's already existed.  As usual, the first
 // return value is only valid if the second one is nil.
@@ -48,7 +53,7 @@ func (r *KataConfigOpenShiftReconciler) createImageMc(machinePool string) (bool,
 
 		err = r.Client.Create(context.TODO(), mc)
 		if err != nil {
-			r.Log.Error(err, "Failed to create a new MachineConfig ", "mc.Name", mc.Name)
+			r.Log.Info("Failed to create a new MachineConfig ", "mc.Name", mc.Name, "err", err)
 			return dummy, err
 		}
 		r.Log.Info("MachineConfig successfully created", "mc.Name", mc.Name)
@@ -78,8 +83,10 @@ func (r *KataConfigOpenShiftReconciler) newMCForCR(machinePool string) (*mcfgv1.
 	}
 
 	if r.FeatureGatesStatus[featuregates.LayeredImageDeployment] {
+		r.Log.Info("Creating MachineConfig for Custom Resource with image")
 		return r.newImageMCForCR(machinePool, icb)
 	} else {
+		r.Log.Info("Creating MachineConfig for Custom Resource with extension")
 		return r.newExtensionMCForCR(machinePool, icb)
 	}
 
@@ -151,3 +158,28 @@ func (r *KataConfigOpenShiftReconciler) newImageMCForCR(machinePool string, icb
 
 	return &mc, nil
 }
+
+// Delete the MachineConfig object
+func (r *KataConfigOpenShiftReconciler) deleteMc(mcName string) error {
+	r.Log.Info("Deleting MachineConfig", "mc.Name", mcName)
+	mc := &mcfgv1.MachineConfig{}
+	err := r.Client.Get(context.TODO(), types.NamespacedName{Name: mcName}, mc)
+	if err != nil {
+		if k8serrors.IsNotFound(err) || k8serrors.IsGone(err) {
+			r.Log.Info("MachineConfig not found. Most likely it was already deleted.")
+			return nil
+		}
+		r.Log.Info("failed to retrieve MachineConfig", "err", err)
+		return err
+	}
+
+	r.Log.Info("deleting MachineConfig")
+	err = r.Client.Delete(context.TODO(), mc)
+	if err != nil {
+		r.Log.Error(err, "Failed to delete MachineConfig")
+		return err
+	}
+
+	r.Log.Info("MachineConfig successfully deleted")
+	return nil
+}

controllers/openshift_controller.go

@@ -59,6 +59,7 @@ type KataConfigOpenShiftReconciler struct {
 	kataConfig         *kataconfigurationv1.KataConfig
 	FeatureGates       *featuregates.FeatureGates
 	FeatureGatesStatus featuregates.FeatureGateStatus
+	deploymentState    DeploymentState
 }
 
 const (
@@ -930,17 +931,61 @@ func (r *KataConfigOpenShiftReconciler) processKataConfigInstallRequest() (ctrl.
 	wasMcJustCreated := false
 
 	// If featuregate LayeredImageDeployment is enabled then create the image based MC
-	// TBD: Handling switching from image based deployment to extension and vice versa
+	// If it's disabled, create the extension based MC
 
 	if r.FeatureGatesStatus[featuregates.LayeredImageDeployment] {
-		wasMcJustCreated, err = r.createImageMc(machinePool)
-		if err != nil {
-			return ctrl.Result{Requeue: true}, nil
+		r.Log.Info("PreviousMcName and PreviousMethod, ImageBasedDeployment=true",
+			"PreviousMcName", r.deploymentState.PreviousMcName, "PreviousMethod", r.deploymentState.PreviousMethod)
+		// Check if the previous deployment method was different
+		// When we first time enter this condition the PreviousMethod will be empty
+		if r.deploymentState.PreviousMethod != "image" {
+			// Rollback the previous deployment
+			if r.deploymentState.PreviousMcName != "" {
+				// Delete the previous MachineConfig
+				err := r.deleteMc(r.deploymentState.PreviousMcName)
+				if err != nil {
+					r.Log.Info("Error deleting previous MachineConfig", "MachineConfig",
+						r.deploymentState.PreviousMcName, "err", err)
+					return ctrl.Result{Requeue: true}, err
+				}
+			}
+			wasMcJustCreated, err = r.createImageMc(machinePool)
+			if err != nil {
+				r.Log.Info("Error creating image MachineConfig for Image based deployment", "err", err)
+				return ctrl.Result{Requeue: true}, err
+			}
+			// Update deployment state
+			r.deploymentState.PreviousMethod = "image"
+			r.deploymentState.PreviousMcName = image_mc_name
 		}
+		// We don't handle any updates to the ImageBasedDeployment configuration
+		r.Log.Info("LayeredImageDeployment is enabled, no updates to the configuration will be handled")
+
 	} else {
-		wasMcJustCreated, err = r.createExtensionMc(machinePool)
-		if err != nil {
-			return ctrl.Result{Requeue: true}, nil
+		r.Log.Info("PreviousMcName and PreviousMethod, ImageBasedDeployment=false",
+			"PreviousMcName", r.deploymentState.PreviousMcName, "PreviousMethod", r.deploymentState.PreviousMethod)
+		// Check if the previous deployment method was different
+		// When we first time enter this condition the PreviousMethod will be empty
+		if r.deploymentState.PreviousMethod != "extension" {
+			// Rollback the previous deployment
+			if r.deploymentState.PreviousMcName != "" {
+				// Delete the previous MachineConfig
+				err := r.deleteMc(r.deploymentState.PreviousMcName)
+				if err != nil {
+					r.Log.Info("Error deleting previous MachineConfig", "MachineConfig",
+						r.deploymentState.PreviousMcName, "err", err)
+					return ctrl.Result{Requeue: true}, err
+				}
+			}
+			wasMcJustCreated, err = r.createExtensionMc(machinePool)
+			if err != nil {
+				r.Log.Info("Error creating extension MachineConfig for Extension based deployment", "err", err)
+				return ctrl.Result{Requeue: true}, err
+			}
+
+			// Update deployment state
+			r.deploymentState.PreviousMethod = "extension"
+			r.deploymentState.PreviousMcName = extension_mc_name
 		}
 	}