operationexecutor

Documentation

Overview

Package operationexecutor implements interfaces that enable execution of attach, detach, mount, and unmount operations with a nestedpendingoperations so that more than one operation is never triggered on the same volume for the same pod.

Index

• type ActualStateOfWorldAttacherUpdater
• type ActualStateOfWorldMounterUpdater
• type AttachedVolume
• type MountedVolume
• type OperationExecutor
  • func NewOperationExecutor(kubeClient internalclientset.Interface, ...) OperationExecutor
• type VolumeToAttach
• type VolumeToMount

Types

type ActualStateOfWorldAttacherUpdater

type ActualStateOfWorldAttacherUpdater interface {
	// Marks the specified volume as attached to the specified node.  If the
	// volume name is supplied, that volume name will be used.  If not, the
	// volume name is computed using the result from querying the plugin.
	//
	// TODO: in the future, we should be able to remove the volumeName
	// argument to this method -- since it is used only for attachable
	// volumes.  See issue 29695.
	MarkVolumeAsAttached(volumeName api.UniqueVolumeName, volumeSpec *volume.Spec, nodeName, devicePath string) error

	// Marks the specified volume as detached from the specified node
	MarkVolumeAsDetached(volumeName api.UniqueVolumeName, nodeName string)

	// Marks desire to detach the specified volume (remove the volume from the node's
	// volumesToReportedAsAttached list)
	RemoveVolumeFromReportAsAttached(volumeName api.UniqueVolumeName, nodeName string) error

	// Unmarks the desire to detach for the specified volume (add the volume back to
	// the node's volumesToReportedAsAttached list)
	AddVolumeToReportAsAttached(volumeName api.UniqueVolumeName, nodeName string)
}

ActualStateOfWorldAttacherUpdater defines a set of operations updating the actual state of the world cache after successful attach/detach/mount/unmount.

type ActualStateOfWorldMounterUpdater

type ActualStateOfWorldMounterUpdater interface {
	// Marks the specified volume as mounted to the specified pod
	MarkVolumeAsMounted(podName volumetypes.UniquePodName, podUID types.UID, volumeName api.UniqueVolumeName, mounter volume.Mounter, outerVolumeSpecName string, volumeGidValue string) error

	// Marks the specified volume as unmounted from the specified pod
	MarkVolumeAsUnmounted(podName volumetypes.UniquePodName, volumeName api.UniqueVolumeName) error

	// Marks the specified volume as having been globally mounted.
	MarkDeviceAsMounted(volumeName api.UniqueVolumeName) error

	// Marks the specified volume as having its global mount unmounted.
	MarkDeviceAsUnmounted(volumeName api.UniqueVolumeName) error
}

ActualStateOfWorldMounterUpdater defines a set of operations updating the actual state of the world cache after successful mount/unmount.

type AttachedVolume

type AttachedVolume struct {
	// VolumeName is the unique identifier for the volume that is attached.
	VolumeName api.UniqueVolumeName

	// VolumeSpec is the volume spec containing the specification for the
	// volume that is attached.
	VolumeSpec *volume.Spec

	// NodeName is the identifier for the node that the volume is attached to.
	NodeName string

	// PluginIsAttachable indicates that the plugin for this volume implements
	// the volume.Attacher interface
	PluginIsAttachable bool

	// DevicePath contains the path on the node where the volume is attached.
	// For non-attachable volumes this is empty.
	DevicePath string
}

AttachedVolume represents a volume that is attached to a node.

type MountedVolume

type MountedVolume struct {
	// PodName is the unique identifier of the pod mounted to.
	PodName volumetypes.UniquePodName

	// VolumeName is the unique identifier of the volume mounted to the pod.
	VolumeName api.UniqueVolumeName

	// InnerVolumeSpecName is the volume.Spec.Name() of the volume. If the
	// volume was referenced through a persistent volume claims, this contains
	// the name of the bound persistent volume object.
	// It is the name that plugins use in their pod mount path, i.e.
	// /var/lib/kubelet/pods/{podUID}/volumes/{escapeQualifiedPluginName}/{innerVolumeSpecName}/
	// PVC example,
	//   apiVersion: v1
	//   kind: PersistentVolume
	//   metadata:
	//     name: pv0003				<- InnerVolumeSpecName
	//   spec:
	//     capacity:
	//       storage: 5Gi
	//     accessModes:
	//       - ReadWriteOnce
	//     persistentVolumeReclaimPolicy: Recycle
	//     nfs:
	//       path: /tmp
	//       server: 172.17.0.2
	// Non-PVC example:
	//   apiVersion: v1
	//   kind: Pod
	//   metadata:
	//     name: test-pd
	//   spec:
	//     containers:
	//     - image: gcr.io/google_containers/test-webserver
	//     	 name: test-container
	//     	 volumeMounts:
	//     	 - mountPath: /test-pd
	//     	   name: test-volume
	//     volumes:
	//     - name: test-volume			<- InnerVolumeSpecName
	//     	 gcePersistentDisk:
	//     	   pdName: my-data-disk
	//     	   fsType: ext4
	InnerVolumeSpecName string

	// outerVolumeSpecName is the podSpec.Volume[x].Name of the volume. If the
	// volume was referenced through a persistent volume claim, this contains
	// the podSpec.Volume[x].Name of the persistent volume claim.
	// PVC example:
	//   kind: Pod
	//   apiVersion: v1
	//   metadata:
	//     name: mypod
	//   spec:
	//     containers:
	//       - name: myfrontend
	//         image: dockerfile/nginx
	//         volumeMounts:
	//         - mountPath: "/var/www/html"
	//           name: mypd
	//     volumes:
	//       - name: mypd				<- OuterVolumeSpecName
	//         persistentVolumeClaim:
	//           claimName: myclaim
	// Non-PVC example:
	//   apiVersion: v1
	//   kind: Pod
	//   metadata:
	//     name: test-pd
	//   spec:
	//     containers:
	//     - image: gcr.io/google_containers/test-webserver
	//     	 name: test-container
	//     	 volumeMounts:
	//     	 - mountPath: /test-pd
	//     	   name: test-volume
	//     volumes:
	//     - name: test-volume			<- OuterVolumeSpecName
	//     	 gcePersistentDisk:
	//     	   pdName: my-data-disk
	//     	   fsType: ext4
	OuterVolumeSpecName string

	// PluginName is the "Unescaped Qualified" name of the volume plugin used to
	// mount and unmount this volume. It can be used to fetch the volume plugin
	// to unmount with, on demand. It is also the name that plugins use, though
	// escaped, in their pod mount path, i.e.
	// /var/lib/kubelet/pods/{podUID}/volumes/{escapeQualifiedPluginName}/{outerVolumeSpecName}/
	PluginName string

	// PodUID is the UID of the pod mounted to. It is also the string used by
	// plugins in their pod mount path, i.e.
	// /var/lib/kubelet/pods/{podUID}/volumes/{escapeQualifiedPluginName}/{outerVolumeSpecName}/
	PodUID types.UID

	// Mounter is the volume mounter used to mount this volume. It is required
	// by kubelet to create container.VolumeMap.
	Mounter volume.Mounter

	// VolumeGidValue contains the value of the GID annotation, if present.
	VolumeGidValue string
}

MountedVolume represents a volume that has successfully been mounted to a pod.

type OperationExecutor

type OperationExecutor interface {
	// AttachVolume attaches the volume to the node specified in volumeToAttach.
	// It then updates the actual state of the world to reflect that.
	AttachVolume(volumeToAttach VolumeToAttach, actualStateOfWorld ActualStateOfWorldAttacherUpdater) error

	// VerifyVolumesAreAttached verifies the given list of volumes to see whether they are still attached to the node.
	// If any volume is not attached right now, it will update the actual state of the world to reflect that.
	// Note that this operation could be operated concurrently with other attach/detach operations.
	// In theory (but very unlikely in practise), race condition among these operations might mark volume as detached
	// even if it is attached. But reconciler can correct this in a short period of time.
	VerifyVolumesAreAttached(AttachedVolumes []AttachedVolume, nodeName string, actualStateOfWorld ActualStateOfWorldAttacherUpdater) error

	// DetachVolume detaches the volume from the node specified in
	// volumeToDetach, and updates the actual state of the world to reflect
	// that. If verifySafeToDetach is set, a call is made to the fetch the node
	// object and it is used to verify that the volume does not exist in Node's
	// Status.VolumesInUse list (operation fails with error if it is).
	DetachVolume(volumeToDetach AttachedVolume, verifySafeToDetach bool, actualStateOfWorld ActualStateOfWorldAttacherUpdater) error

	// MountVolume mounts the volume to the pod specified in volumeToMount.
	// Specifically it will:
	// * Wait for the device to finish attaching (for attachable volumes only).
	// * Mount device to global mount path (for attachable volumes only).
	// * Update actual state of world to reflect volume is globally mounted (for
	//   attachable volumes only).
	// * Mount the volume to the pod specific path.
	// * Update actual state of world to reflect volume is mounted to the pod
	//   path.
	MountVolume(waitForAttachTimeout time.Duration, volumeToMount VolumeToMount, actualStateOfWorld ActualStateOfWorldMounterUpdater) error

	// UnmountVolume unmounts the volume from the pod specified in
	// volumeToUnmount and updates the actual state of the world to reflect that.
	UnmountVolume(volumeToUnmount MountedVolume, actualStateOfWorld ActualStateOfWorldMounterUpdater) error

	// UnmountDevice unmounts the volumes global mount path from the device (for
	// attachable volumes only, freeing it for detach. It then updates the
	// actual state of the world to reflect that.
	UnmountDevice(deviceToDetach AttachedVolume, actualStateOfWorld ActualStateOfWorldMounterUpdater, mounter mount.Interface) error

	// VerifyControllerAttachedVolume checks if the specified volume is present
	// in the specified nodes AttachedVolumes Status field. It uses kubeClient
	// to fetch the node object.
	// If the volume is found, the actual state of the world is updated to mark
	// the volume as attached.
	// If the volume does not implement the attacher interface, it is assumed to
	// be attached and the the actual state of the world is updated accordingly.
	// If the volume is not found or there is an error (fetching the node
	// object, for example) then an error is returned which triggers exponential
	// back off on retries.
	VerifyControllerAttachedVolume(volumeToMount VolumeToMount, nodeName string, actualStateOfWorld ActualStateOfWorldAttacherUpdater) error

	// IsOperationPending returns true if an operation for the given volumeName and podName is pending,
	// otherwise it returns false
	IsOperationPending(volumeName api.UniqueVolumeName, podName volumetypes.UniquePodName) bool
}

OperationExecutor defines a set of operations for attaching, detaching, mounting, or unmounting a volume that are executed with a NewNestedPendingOperations which prevents more than one operation from being triggered on the same volume.

These operations should be idempotent (for example, AttachVolume should still succeed if the volume is already attached to the node, etc.). However, they depend on the volume plugins to implement this behavior.

Once an operation completes successfully, the actualStateOfWorld is updated to indicate the volume is attached/detached/mounted/unmounted.

If the OperationExecutor fails to start the operation because, for example, an operation with the same UniqueVolumeName is already pending, a non-nil error is returned.

Once the operation is started, since it is executed asynchronously, errors are simply logged and the goroutine is terminated without updating actualStateOfWorld (callers are responsible for retrying as needed).

Some of these operations may result in calls to the API server; callers are responsible for rate limiting on errors.

func NewOperationExecutor

func NewOperationExecutor(
	kubeClient internalclientset.Interface,
	volumePluginMgr *volume.VolumePluginMgr,
	recorder record.EventRecorder,
	checkNodeCapabilitiesBeforeMount bool) OperationExecutor

NewOperationExecutor returns a new instance of OperationExecutor.

type VolumeToAttach

type VolumeToAttach struct {
	// VolumeName is the unique identifier for the volume that should be
	// attached.
	VolumeName api.UniqueVolumeName

	// VolumeSpec is a volume spec containing the specification for the volume
	// that should be attached.
	VolumeSpec *volume.Spec

	// NodeName is the identifier for the node that the volume should be
	// attached to.
	NodeName string

	// scheduledPods is a map containing the set of pods that reference this
	// volume and are scheduled to the underlying node. The key in the map is
	// the name of the pod and the value is a pod object containing more
	// information about the pod.
	ScheduledPods []*api.Pod
}

VolumeToAttach represents a volume that should be attached to a node.

type VolumeToMount

type VolumeToMount struct {
	// VolumeName is the unique identifier for the volume that should be
	// mounted.
	VolumeName api.UniqueVolumeName

	// PodName is the unique identifier for the pod that the volume should be
	// mounted to after it is attached.
	PodName volumetypes.UniquePodName

	// VolumeSpec is a volume spec containing the specification for the volume
	// that should be mounted. Used to create NewMounter. Used to generate
	// InnerVolumeSpecName.
	VolumeSpec *volume.Spec

	// outerVolumeSpecName is the podSpec.Volume[x].Name of the volume. If the
	// volume was referenced through a persistent volume claim, this contains
	// the podSpec.Volume[x].Name of the persistent volume claim.
	OuterVolumeSpecName string

	// Pod to mount the volume to. Used to create NewMounter.
	Pod *api.Pod

	// PluginIsAttachable indicates that the plugin for this volume implements
	// the volume.Attacher interface
	PluginIsAttachable bool

	// VolumeGidValue contains the value of the GID annotation, if present.
	VolumeGidValue string

	// DevicePath contains the path on the node where the volume is attached.
	// For non-attachable volumes this is empty.
	DevicePath string

	// ReportedInUse indicates that the volume was successfully added to the
	// VolumesInUse field in the node's status.
	ReportedInUse bool
}

VolumeToMount represents a volume that should be attached to this node and mounted to the PodName.