cache

Documentation

Overview

Package cache implements data structures used by the attach/detach controller to keep track of volumes, the nodes they are attached to, and the pods that reference them.

Package cache implements data structures used by the attach/detach controller to keep track of volumes, the nodes they are attached to, and the pods that reference them.

Index

• type ActualStateOfWorld
  • func NewActualStateOfWorld(volumePluginMgr *volume.VolumePluginMgr) ActualStateOfWorld
• type AttachedVolume
• type DesiredStateOfWorld
  • func NewDesiredStateOfWorld(volumePluginMgr *volume.VolumePluginMgr) DesiredStateOfWorld
• type VolumeToAttach

Types

type ActualStateOfWorld

type ActualStateOfWorld interface {
	// AddVolumeNode adds the given volume and node to the underlying store
	// indicating the specified volume is attached to the specified node.
	// A unique volumeName is generated from the volumeSpec and returned on
	// success.
	// If the volume/node combo already exists, this is a no-op.
	// If volumeSpec is not an attachable volume plugin, an error is returned.
	// If no volume with the name volumeName exists in the store, the volume is
	// added.
	// If no node with the name nodeName exists in list of attached nodes for
	// the specified volume, the node is added.
	AddVolumeNode(volumeSpec *volume.Spec, nodeName string) (string, error)

	// MarkVolumeNodeSafeToDetach marks the given volume as safe to detach from
	// the given node.
	// If no volume with the name volumeName exists in the store, an error is
	// returned.
	// If no node with the name nodeName exists in list of attached nodes for
	// the specified volume, an error is returned.
	MarkVolumeNodeSafeToDetach(volumeName, nodeName string) error

	// MarkDesireToDetach returns the difference between the current time  and
	// the DetachRequestedTime for the given volume/node combo. If the
	// DetachRequestedTime is zero, it is set to the current time.
	// If no volume with the name volumeName exists in the store, an error is
	// returned.
	// If no node with the name nodeName exists in list of attached nodes for
	// the specified volume, an error is returned.
	MarkDesireToDetach(volumeName, nodeName string) (time.Duration, error)

	// DeleteVolumeNode removes the given volume and node from the underlying
	// store indicating the specified volume is no longer attached to the
	// specified node.
	// If the volume/node combo does not exist, this is a no-op.
	// If after deleting the node, the specified volume contains no other child
	// nodes, the volume is also deleted.
	DeleteVolumeNode(volumeName, nodeName string)

	// VolumeNodeExists returns true if the specified volume/node combo exists
	// in the underlying store indicating the specified volume is attached to
	// the specified node.
	VolumeNodeExists(volumeName, nodeName string) bool

	// GetAttachedVolumes generates and returns a list of volumes/node pairs
	// reflecting which volumes are attached to which nodes based on the
	// current actual state of the world.
	GetAttachedVolumes() []AttachedVolume
}

ActualStateOfWorld defines a set of thread-safe operations supported on the attach/detach controller's actual state of the world cache. This cache contains volumes->nodes i.e. a set of all volumes and the nodes the attach/detach controller believes are successfully attached.

func NewActualStateOfWorld

func NewActualStateOfWorld(volumePluginMgr *volume.VolumePluginMgr) ActualStateOfWorld

NewActualStateOfWorld returns a new instance of ActualStateOfWorld.

type AttachedVolume

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

	// 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

	// SafeToDetach indicates that this volume has been been unmounted from the
	// node and is safe to detach.
	// The value is set by MarkVolumeNodeSafeToDetach(...) and  reset on
	// AddVolumeNode(...) calls.
	SafeToDetach bool

	// DetachRequestedTime is used to capture the desire to detach this volume.
	// When the volume is newly created this value is set to time zero.
	// It is set to current time, when MarkDesireToDetach(...) is called, if it
	// was previously set to zero (other wise its value remains the same).
	// It is reset to zero on AddVolumeNode(...) calls.
	DetachRequestedTime time.Time
}

AttachedVolume represents a volume that is attached to a node.

type DesiredStateOfWorld

type DesiredStateOfWorld interface {
	// AddNode adds the given node to the list of nodes managed by the attach/
	// detach controller.
	// If the node already exists this is a no-op.
	AddNode(nodeName string)

	// AddPod adds the given pod to the list of pods that reference the
	// specified volume and is scheduled to the specified node.
	// A unique volumeName is generated from the volumeSpec and returned on
	// success.
	// If the pod already exists under the specified volume, this is a no-op.
	// If volumeSpec is not an attachable volume plugin, an error is returned.
	// If no volume with the name volumeName exists in the list of volumes that
	// should be attached to the specified node, the volume is implicitly added.
	// If no node with the name nodeName exists in list of nodes managed by the
	// attach/detach attached controller, an error is returned.
	AddPod(podName string, volumeSpec *volume.Spec, nodeName string) (string, error)

	// DeleteNode removes the given node from the list of nodes managed by the
	// attach/detach controller.
	// If the node does not exist this is a no-op.
	// If the node exists but has 1 or more child volumes, an error is returned.
	DeleteNode(nodeName string) error

	// DeletePod removes the given pod from the list of pods that reference the
	// specified volume and are scheduled to the specified node.
	// If no pod exists in the list of pods that reference the specified volume
	// and are scheduled to the specified node, this is a no-op.
	// If a node with the name nodeName does not exist in the list of nodes
	// managed by the attach/detach attached controller, this is a no-op.
	// If no volume with the name volumeName exists in the list of managed
	// volumes under the specified node, this is a no-op.
	// If after deleting the pod, the specified volume contains no other child
	// pods, the volume is also deleted.
	DeletePod(podName, volumeName, nodeName string)

	// NodeExists returns true if the node with the specified name exists in
	// the list of nodes managed by the attach/detach controller.
	NodeExists(nodeName string) bool

	// VolumeExists returns true if the volume with the specified name exists
	// in the list of volumes that should be attached to the specified node by
	// the attach detach controller.
	VolumeExists(volumeName, nodeName string) bool

	// GetVolumesToAttach generates and returns a list of volumes to attach
	// and the nodes they should be attached to based on the current desired
	// state of the world.
	GetVolumesToAttach() []VolumeToAttach
}

DesiredStateOfWorld defines a set of thread-safe operations supported on the attach/detach controller's desired state of the world cache. This cache contains nodes->volumes->pods where nodes are all the nodes managed by the attach/detach controller, volumes are all the volumes that should be attached to the specified node, and pods are the pods that reference the volume and are scheduled to that node.

func NewDesiredStateOfWorld

func NewDesiredStateOfWorld(volumePluginMgr *volume.VolumePluginMgr) DesiredStateOfWorld

NewDesiredStateOfWorld returns a new instance of DesiredStateOfWorld.

type VolumeToAttach

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

	// 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
}

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