fix regression in UX experience for double attach volume

send event when volume is not allowed to multi-attach

pkg/controller/volume/attachdetach/attach_detach_controller.go

@@ -144,7 +144,8 @@ func NewAttachDetachController(
 		adc.desiredStateOfWorld,
 		adc.actualStateOfWorld,
 		adc.attacherDetacher,
-		adc.nodeStatusUpdater)
+		adc.nodeStatusUpdater,
+		recorder)
 
 	adc.desiredStateOfWorldPopulator = populator.NewDesiredStateOfWorldPopulator(
 		desiredStateOfWorldPopulatorLoopSleepPeriod,

pkg/controller/volume/attachdetach/cache/desired_state_of_world.go

@@ -158,6 +158,10 @@ type nodeManaged struct {
 
 // The volume object represents a volume that should be attached to a node.
 type volumeToAttach struct {
+	// multiAttachErrorReported indicates whether the multi-attach error has been reported for the given volume.
+	// It is used to to prevent reporting the error from being reported more than once for a given volume.
+	multiAttachErrorReported bool
+
 	// volumeName contains the unique identifier for this volume.
 	volumeName v1.UniqueVolumeName
 
@@ -231,9 +235,10 @@ func (dsw *desiredStateOfWorld) AddPod(
 	volumeObj, volumeExists := nodeObj.volumesToAttach[volumeName]
 	if !volumeExists {
 		volumeObj = volumeToAttach{
-			volumeName:    volumeName,
-			spec:          volumeSpec,
-			scheduledPods: make(map[types.UniquePodName]pod),
+			multiAttachErrorReported: false,
+			volumeName:               volumeName,
+			spec:                     volumeSpec,
+			scheduledPods:            make(map[types.UniquePodName]pod),
 		}
 		dsw.nodesManaged[nodeName].volumesToAttach[volumeName] = volumeObj
 	}
@@ -349,10 +354,11 @@ func (dsw *desiredStateOfWorld) GetVolumesToAttach() []VolumeToAttach {
 			volumesToAttach = append(volumesToAttach,
 				VolumeToAttach{
 					VolumeToAttach: operationexecutor.VolumeToAttach{
-						VolumeName:    volumeName,
-						VolumeSpec:    volumeObj.spec,
-						NodeName:      nodeName,
-						ScheduledPods: getPodsFromMap(volumeObj.scheduledPods),
+						MultiAttachErrorReported: volumeObj.multiAttachErrorReported,
+						VolumeName:               volumeName,
+						VolumeSpec:               volumeObj.spec,
+						NodeName:                 nodeName,
+						ScheduledPods:            getPodsFromMap(volumeObj.scheduledPods),
 					}})
 		}
 	}

pkg/controller/volume/attachdetach/reconciler/BUILD

@@ -16,11 +16,13 @@ go_library(
         "//pkg/api/v1:go_default_library",
         "//pkg/controller/volume/attachdetach/cache:go_default_library",
         "//pkg/controller/volume/attachdetach/statusupdater:go_default_library",
+        "//pkg/kubelet/events:go_default_library",
         "//pkg/util/goroutinemap/exponentialbackoff:go_default_library",
         "//pkg/volume:go_default_library",
         "//pkg/volume/util/operationexecutor:go_default_library",
         "//vendor/github.com/golang/glog:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/wait:go_default_library",
+        "//vendor/k8s.io/client-go/tools/record:go_default_library",
     ],
 )
 

pkg/controller/volume/attachdetach/reconciler/reconciler.go

@@ -25,9 +25,11 @@ import (
 
 	"github.com/golang/glog"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/tools/record"
 	"k8s.io/kubernetes/pkg/api/v1"
 	"k8s.io/kubernetes/pkg/controller/volume/attachdetach/cache"
 	"k8s.io/kubernetes/pkg/controller/volume/attachdetach/statusupdater"
+	kevents "k8s.io/kubernetes/pkg/kubelet/events"
 	"k8s.io/kubernetes/pkg/util/goroutinemap/exponentialbackoff"
 	"k8s.io/kubernetes/pkg/volume"
 	"k8s.io/kubernetes/pkg/volume/util/operationexecutor"
@@ -63,7 +65,8 @@ func NewReconciler(
 	desiredStateOfWorld cache.DesiredStateOfWorld,
 	actualStateOfWorld cache.ActualStateOfWorld,
 	attacherDetacher operationexecutor.OperationExecutor,
-	nodeStatusUpdater statusupdater.NodeStatusUpdater) Reconciler {
+	nodeStatusUpdater statusupdater.NodeStatusUpdater,
+	recorder record.EventRecorder) Reconciler {
 	return &reconciler{
 		loopPeriod:                loopPeriod,
 		maxWaitForUnmountDuration: maxWaitForUnmountDuration,
@@ -74,6 +77,7 @@ func NewReconciler(
 		attacherDetacher:          attacherDetacher,
 		nodeStatusUpdater:         nodeStatusUpdater,
 		timeOfLastSync:            time.Now(),
+		recorder:                  recorder,
 	}
 }
 
@@ -87,6 +91,7 @@ type reconciler struct {
 	nodeStatusUpdater         statusupdater.NodeStatusUpdater
 	timeOfLastSync            time.Time
 	disableReconciliationSync bool
+	recorder                  record.EventRecorder
 }
 
 func (rc *reconciler) Run(stopCh <-chan struct{}) {
@@ -248,7 +253,14 @@ func (rc *reconciler) reconcile() {
 			if rc.isMultiAttachForbidden(volumeToAttach.VolumeSpec) {
 				nodes := rc.actualStateOfWorld.GetNodesForVolume(volumeToAttach.VolumeName)
 				if len(nodes) > 0 {
-					glog.V(4).Infof("Volume %q is already exclusively attached to node %q and can't be attached to %q", volumeToAttach.VolumeName, nodes, volumeToAttach.NodeName)
+					if !volumeToAttach.MultiAttachErrorReported {
+						simpleMsg, detailedMsg := volumeToAttach.GenerateMsg("Multi-Attach error", "Volume is already exclusively attached to one node and can't be attached to another")
+						for _, pod := range volumeToAttach.ScheduledPods {
+							rc.recorder.Eventf(pod, v1.EventTypeWarning, kevents.FailedAttachVolume, simpleMsg)
+						}
+						volumeToAttach.MultiAttachErrorReported = true
+						glog.Warningf(detailedMsg)
+					}
 					continue
 				}
 			}

pkg/controller/volume/attachdetach/reconciler/reconciler_test.go

@@ -55,7 +55,7 @@ func Test_Run_Positive_DoNothing(t *testing.T) {
 	nsu := statusupdater.NewNodeStatusUpdater(
 		fakeKubeClient, informerFactory.Core().V1().Nodes().Lister(), asw)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 
 	// Act
 	ch := make(chan struct{})
@@ -83,7 +83,7 @@ func Test_Run_Positive_OneDesiredVolumeAttach(t *testing.T) {
 	ad := operationexecutor.NewOperationExecutor(operationexecutor.NewOperationGenerator(fakeKubeClient, volumePluginMgr, fakeRecorder, false /* checkNodeCapabilitiesBeforeMount */))
 	nsu := statusupdater.NewFakeNodeStatusUpdater(false /* returnError */)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 	podName := "pod-uid"
 	volumeName := v1.UniqueVolumeName("volume-name")
 	volumeSpec := controllervolumetesting.GetTestVolumeSpec(string(volumeName), volumeName)
@@ -129,7 +129,7 @@ func Test_Run_Positive_OneDesiredVolumeAttachThenDetachWithUnmountedVolume(t *te
 	ad := operationexecutor.NewOperationExecutor(operationexecutor.NewOperationGenerator(fakeKubeClient, volumePluginMgr, fakeRecorder, false /* checkNodeCapabilitiesBeforeMount */))
 	nsu := statusupdater.NewFakeNodeStatusUpdater(false /* returnError */)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 	podName := "pod-uid"
 	volumeName := v1.UniqueVolumeName("volume-name")
 	volumeSpec := controllervolumetesting.GetTestVolumeSpec(string(volumeName), volumeName)
@@ -196,7 +196,7 @@ func Test_Run_Positive_OneDesiredVolumeAttachThenDetachWithMountedVolume(t *test
 	ad := operationexecutor.NewOperationExecutor(operationexecutor.NewOperationGenerator(fakeKubeClient, volumePluginMgr, fakeRecorder, false /* checkNodeCapabilitiesBeforeMount */))
 	nsu := statusupdater.NewFakeNodeStatusUpdater(false /* returnError */)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 	podName := "pod-uid"
 	volumeName := v1.UniqueVolumeName("volume-name")
 	volumeSpec := controllervolumetesting.GetTestVolumeSpec(string(volumeName), volumeName)
@@ -263,7 +263,7 @@ func Test_Run_Negative_OneDesiredVolumeAttachThenDetachWithUnmountedVolumeUpdate
 	ad := operationexecutor.NewOperationExecutor(operationexecutor.NewOperationGenerator(fakeKubeClient, volumePluginMgr, fakeRecorder, false /* checkNodeCapabilitiesBeforeMount */))
 	nsu := statusupdater.NewFakeNodeStatusUpdater(true /* returnError */)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 	podName := "pod-uid"
 	volumeName := v1.UniqueVolumeName("volume-name")
 	volumeSpec := controllervolumetesting.GetTestVolumeSpec(string(volumeName), volumeName)
@@ -333,7 +333,7 @@ func Test_Run_OneVolumeAttachAndDetachMultipleNodesWithReadWriteMany(t *testing.
 	ad := operationexecutor.NewOperationExecutor(operationexecutor.NewOperationGenerator(fakeKubeClient, volumePluginMgr, fakeRecorder, false /* checkNodeCapabilitiesBeforeMount */))
 	nsu := statusupdater.NewFakeNodeStatusUpdater(false /* returnError */)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 	podName1 := "pod-uid1"
 	podName2 := "pod-uid2"
 	volumeName := v1.UniqueVolumeName("volume-name")
@@ -423,7 +423,7 @@ func Test_Run_OneVolumeAttachAndDetachMultipleNodesWithReadWriteOnce(t *testing.
 	ad := operationexecutor.NewOperationExecutor(operationexecutor.NewOperationGenerator(fakeKubeClient, volumePluginMgr, fakeRecorder, false /* checkNodeCapabilitiesBeforeMount */))
 	nsu := statusupdater.NewFakeNodeStatusUpdater(false /* returnError */)
 	reconciler := NewReconciler(
-		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu)
+		reconcilerLoopPeriod, maxWaitForUnmountDuration, syncLoopPeriod, false, dsw, asw, ad, nsu, fakeRecorder)
 	podName1 := "pod-uid1"
 	podName2 := "pod-uid2"
 	volumeName := v1.UniqueVolumeName("volume-name")

pkg/kubelet/events/event.go

@@ -47,6 +47,7 @@ const (
 	NodeNotSchedulable                   = "NodeNotSchedulable"
 	StartingKubelet                      = "Starting"
 	KubeletSetupFailed                   = "KubeletSetupFailed"
+	FailedAttachVolume                   = "FailedAttachVolume"
 	FailedDetachVolume                   = "FailedDetachVolume"
 	FailedMountVolume                    = "FailedMount"
 	FailedUnMountVolume                  = "FailedUnMount"

pkg/volume/util/operationexecutor/operation_executor.go

@@ -211,6 +211,10 @@ func generateVolumeMsg(prefixMsg, suffixMsg, volumeName, details string) (simple
 
 // VolumeToAttach represents a volume that should be attached to a node.
 type VolumeToAttach struct {
+	// MultiAttachErrorReported indicates whether the multi-attach error has been reported for the given volume.
+	// It is used to to prevent reporting the error from being reported more than once for a given volume.
+	MultiAttachErrorReported bool
+
 	// VolumeName is the unique identifier for the volume that should be
 	// attached.
 	VolumeName v1.UniqueVolumeName