Inhibit scale-down by autoscaler during roll-outs.

cmd/machine-controller-manager/app/controllermanager.go

@@ -273,6 +273,7 @@ func StartControllers(s *options.MCMServer,
 			s.NodeConditions,
 			s.BootstrapTokenAuthExtraGroups,
 			s.DeleteMigratedMachineClass,
+			s.AutoscalerScaleDownAnnotationDuringRollout,
 		)
 		if err != nil {
 			return err

cmd/machine-controller-manager/app/options/options.go

@@ -62,6 +62,7 @@ func NewMCMServer() *MCMServer {
 			KubeAPIBurst:            30,
 			LeaderElection:          leaderelectionconfig.DefaultLeaderElectionConfiguration(),
 			ControllerStartInterval: metav1.Duration{Duration: 0 * time.Second},
+			AutoscalerScaleDownAnnotationDuringRollout: true,
 			SafetyOptions: machineconfig.SafetyOptions{
 				SafetyUp:                                 2,
 				SafetyDown:                               1,
@@ -115,6 +116,8 @@ func (s *MCMServer) AddFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&s.BootstrapTokenAuthExtraGroups, "bootstrap-token-auth-extra-groups", s.BootstrapTokenAuthExtraGroups, "Comma-separated list of groups to set bootstrap token's \"auth-extra-groups\" field to")
 	fs.BoolVar(&s.DeleteMigratedMachineClass, "delete-migrated-machine-class", false, "Deletes any (provider specific) machine class that has the machine.sapcloud.io/migrated annotation")
 
+	fs.BoolVar(&s.AutoscalerScaleDownAnnotationDuringRollout, "autoscaler-scaldown-annotation-during-rollout", true, "Add cluster autoscaler scale-down disabled annotation during roll-out.")
+
 	leaderelectionconfig.BindFlags(&s.LeaderElection, fs)
 	// TODO: DefaultFeatureGate is global and it adds all k8s flags
 	// utilfeature.DefaultFeatureGate.AddFlag(fs)

pkg/controller/controller.go

@@ -81,32 +81,34 @@ func NewController(
 	nodeConditions string,
 	bootstrapTokenAuthExtraGroups string,
 	deleteMigratedMachineClass bool,
+	autoscalerScaleDownAnnotationDuringRollout bool,
 ) (Controller, error) {
 	controller := &controller{
-		namespace:                      namespace,
-		controlMachineClient:           controlMachineClient,
-		controlCoreClient:              controlCoreClient,
-		targetCoreClient:               targetCoreClient,
-		recorder:                       recorder,
-		expectations:                   NewUIDTrackingContExpectations(NewContExpectations()),
-		secretQueue:                    workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "secret"),
-		nodeQueue:                      workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "node"),
-		openStackMachineClassQueue:     workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "openstackmachineclass"),
-		awsMachineClassQueue:           workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "awsmachineclass"),
-		azureMachineClassQueue:         workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "azuremachineclass"),
-		gcpMachineClassQueue:           workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "gcpmachineclass"),
-		alicloudMachineClassQueue:      workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "alicloudmachineclass"),
-		packetMachineClassQueue:        workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "packetmachineclass"),
-		machineQueue:                   workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machine"),
-		machineSetQueue:                workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machineset"),
-		machineDeploymentQueue:         workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinedeployment"),
-		machineSafetyOrphanVMsQueue:    workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinesafetyorphanvms"),
-		machineSafetyOvershootingQueue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinesafetyovershooting"),
-		machineSafetyAPIServerQueue:    workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinesafetyapiserver"),
-		safetyOptions:                  safetyOptions,
-		nodeConditions:                 nodeConditions,
-		bootstrapTokenAuthExtraGroups:  bootstrapTokenAuthExtraGroups,
-		deleteMigratedMachineClass:     deleteMigratedMachineClass,
+		namespace:                                  namespace,
+		controlMachineClient:                       controlMachineClient,
+		controlCoreClient:                          controlCoreClient,
+		targetCoreClient:                           targetCoreClient,
+		recorder:                                   recorder,
+		expectations:                               NewUIDTrackingContExpectations(NewContExpectations()),
+		secretQueue:                                workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "secret"),
+		nodeQueue:                                  workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "node"),
+		openStackMachineClassQueue:                 workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "openstackmachineclass"),
+		awsMachineClassQueue:                       workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "awsmachineclass"),
+		azureMachineClassQueue:                     workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "azuremachineclass"),
+		gcpMachineClassQueue:                       workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "gcpmachineclass"),
+		alicloudMachineClassQueue:                  workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "alicloudmachineclass"),
+		packetMachineClassQueue:                    workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "packetmachineclass"),
+		machineQueue:                               workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machine"),
+		machineSetQueue:                            workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machineset"),
+		machineDeploymentQueue:                     workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinedeployment"),
+		machineSafetyOrphanVMsQueue:                workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinesafetyorphanvms"),
+		machineSafetyOvershootingQueue:             workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinesafetyovershooting"),
+		machineSafetyAPIServerQueue:                workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "machinesafetyapiserver"),
+		safetyOptions:                              safetyOptions,
+		nodeConditions:                             nodeConditions,
+		bootstrapTokenAuthExtraGroups:              bootstrapTokenAuthExtraGroups,
+		deleteMigratedMachineClass:                 deleteMigratedMachineClass,
+		autoscalerScaleDownAnnotationDuringRollout: autoscalerScaleDownAnnotationDuringRollout,
 	}
 
 	controller.internalExternalScheme = runtime.NewScheme()
@@ -398,10 +400,11 @@ type Controller interface {
 
 // controller is a concrete Controller.
 type controller struct {
-	namespace                     string
-	nodeConditions                string
-	bootstrapTokenAuthExtraGroups string
-	deleteMigratedMachineClass    bool
+	namespace                                  string
+	nodeConditions                             string
+	bootstrapTokenAuthExtraGroups              string
+	deleteMigratedMachineClass                 bool
+	autoscalerScaleDownAnnotationDuringRollout bool
 
 	controlMachineClient machineapi.MachineV1alpha1Interface
 	controlCoreClient    kubernetes.Interface

pkg/controller/controller_utils.go

@@ -33,10 +33,12 @@ import (
 	"sync/atomic"
 	"time"
 
+	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/validation"
 
 	"github.com/gardener/machine-controller-manager/pkg/apis/machine/v1alpha1"
 	machineapi "github.com/gardener/machine-controller-manager/pkg/client/clientset/versioned/typed/machine/v1alpha1"
+	annotationsutils "github.com/gardener/machine-controller-manager/pkg/util/annotations"
 	conditionutils "github.com/gardener/machine-controller-manager/pkg/util/conditions"
 	hashutil "github.com/gardener/machine-controller-manager/pkg/util/hash"
 	taintutils "github.com/gardener/machine-controller-manager/pkg/util/taints"
@@ -96,6 +98,13 @@ var Backoff = wait.Backoff{
 	Jitter:   1.0,
 }
 
+// UpdateAnnotationBackoff is the backoff period used while updating the annotation
+var UpdateAnnotationBackoff = wait.Backoff{
+	Steps:    5,
+	Duration: 100 * time.Millisecond,
+	Jitter:   1.0,
+}
+
 var (
 	// KeyFunc is the variable that stores the function that retreives the object key from an object
 	KeyFunc = cache.DeletionHandlingMetaNamespaceKeyFunc
@@ -1111,3 +1120,122 @@ func ComputeHash(template *v1alpha1.MachineTemplateSpec, collisionCount *int32)
 
 	return machineTemplateSpecHasher.Sum32()
 }
+
+// AddOrUpdateAnnotationOnNode add annotations to the node. If annotation was added into node, it'll issue API calls
+// to update nodes; otherwise, no API calls. Return error if any.
+func AddOrUpdateAnnotationOnNode(c clientset.Interface, nodeName string, annotations map[string]string) error {
+	if annotations == nil {
+		return nil
+	}
+	firstTry := true
+	return clientretry.RetryOnConflict(UpdateAnnotationBackoff, func() error {
+		var err error
+		var oldNode *v1.Node
+		// First we try getting node from the API server cache, as it's cheaper. If it fails
+		// we get it from etcd to be sure to have fresh data.
+		if firstTry {
+			oldNode, err = c.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{ResourceVersion: "0"})
+			firstTry = false
+		} else {
+			oldNode, err = c.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+		}
+		if errors.IsNotFound(err) {
+			klog.Warningf("Node %s not found while updating annotation. Err: %v", nodeName, err)
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+
+		var newNode *v1.Node
+		updated := false
+
+		newNode, updated, err = annotationsutils.AddOrUpdateAnnotation(oldNode, annotations)
+
+		if !updated {
+			return nil
+		}
+		return UpdateNodeAnnotations(c, nodeName, oldNode, newNode)
+	})
+}
+
+// UpdateNodeAnnotations is for updating the node annotations from oldNode to the newNode
+// using the nodes Update() method
+func UpdateNodeAnnotations(c clientset.Interface, nodeName string, oldNode *v1.Node, newNode *v1.Node) error {
+	newNodeClone := oldNode.DeepCopy()
+	newNodeClone.Annotations = newNode.Annotations
+
+	_, err := c.CoreV1().Nodes().Update(newNodeClone)
+	if err != nil {
+		return fmt.Errorf("failed to create or update annotations for node %q: %v", nodeName, err)
+	}
+
+	return err
+}
+
+// RemoveAnnotationsOffNode is for cleaning up annotations temporarily added to node,
+// won't fail if target annotation doesn't exist or has been removed.
+// If passed a node it'll check if there's anything to be done, if annotation is not present it won't issue
+// any API calls.
+func RemoveAnnotationsOffNode(c clientset.Interface, nodeName string, annotations map[string]string) error {
+
+	// Short circuit if annotation doesnt exist for limiting API calls.
+	if annotations == nil || nodeName == "" {
+		return nil
+	}
+
+	firstTry := true
+	return clientretry.RetryOnConflict(UpdateAnnotationBackoff, func() error {
+		var err error
+		var oldNode *v1.Node
+		// First we try getting node from the API server cache, as it's cheaper. If it fails
+		// we get it from etcd to be sure to have fresh data.
+		if firstTry {
+			oldNode, err = c.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{ResourceVersion: "0"})
+			firstTry = false
+		} else {
+			oldNode, err = c.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+		}
+		if errors.IsNotFound(err) {
+			klog.Warningf("Node %s not found while removing annotation. Err: %v", nodeName, err)
+			return nil
+		}
+
+		if err != nil {
+			return err
+		}
+
+		var newNode *v1.Node
+		oldNodeCopy := oldNode
+		updated := false
+
+		// Remove the annotations from the node.
+		newNode, updated, err = annotationsutils.RemoveAnnotation(oldNodeCopy, annotations)
+
+		if !updated {
+			return nil
+		}
+		return UpdateNodeAnnotations(c, nodeName, oldNode, newNode)
+	})
+}
+
+// GetAnnotationsFromNode returns all the annotations of the provided node.
+func GetAnnotationsFromNode(c clientset.Interface, nodeName string) (map[string]string, error) {
+
+	// Short circuit if annotation doesnt exist for limiting API calls.
+	if nodeName == "" {
+		return nil, nil
+	}
+
+	node, err := c.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
+	if errors.IsNotFound(err) {
+		klog.Warningf("Node %s not found while fetching annotation. Err: %v", nodeName, err)
+		return nil, nil
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	return node.Annotations, nil
+}