volume

Documentation

Overview

Package volume includes internal representations of external volume types as well as utility methods required to mount/unmount volumes to kubelets.

Index

• func CalculateTimeoutForVolume(minimumTimeout, timeoutIncrement int, pv *api.PersistentVolume) int64
• func NewFakeVolumeHost(rootDir string, kubeClient client.Interface, plugins []VolumePlugin) *fakeVolumeHost
• func NewPersistentVolumeRecyclerPodTemplate() *api.Pod
• func RecycleVolumeByWatchingPodUntilCompletion(pod *api.Pod, kubeClient client.Interface) error
• func RenameDirectory(oldPath, newName string) (string, error)
• type Builder
• type Cleaner
• type CreatableVolumePlugin
• type Creater
• type DeletableVolumePlugin
• type Deleter
• type FakeDeleter
  • func (fd *FakeDeleter) Delete() error
  • func (fd *FakeDeleter) GetPath() string
• type FakeVolume
  • func (fv *FakeVolume) GetPath() string
  • func (fv *FakeVolume) IsReadOnly() bool
  • func (fv *FakeVolume) SetUp() error
  • func (fv *FakeVolume) SetUpAt(dir string) error
  • func (fv *FakeVolume) TearDown() error
  • func (fv *FakeVolume) TearDownAt(dir string) error
• type FakeVolumePlugin
  • func (plugin *FakeVolumePlugin) CanSupport(spec *Spec) bool
  • func (plugin *FakeVolumePlugin) GetAccessModes() []api.PersistentVolumeAccessMode
  • func (plugin *FakeVolumePlugin) Init(host VolumeHost)
  • func (plugin *FakeVolumePlugin) Name() string
  • func (plugin *FakeVolumePlugin) NewBuilder(spec *Spec, pod *api.Pod, opts VolumeOptions) (Builder, error)
  • func (plugin *FakeVolumePlugin) NewCleaner(volName string, podUID types.UID) (Cleaner, error)
  • func (plugin *FakeVolumePlugin) NewDeleter(spec *Spec) (Deleter, error)
  • func (plugin *FakeVolumePlugin) NewRecycler(spec *Spec) (Recycler, error)
• type PersistentVolumePlugin
• type RecyclableVolumePlugin
• type Recycler
  • func NewFakeRecycler(spec *Spec, host VolumeHost, config VolumeConfig) (Recycler, error)
• type Spec
  • func NewSpecFromPersistentVolume(pv *api.PersistentVolume, readOnly bool) *Spec
  • func NewSpecFromVolume(vs *api.Volume) *Spec
  • func (spec *Spec) Name() string
• type Volume
• type VolumeConfig
• type VolumeHost
• type VolumeOptions
• type VolumePlugin
  • func ProbeVolumePlugins(config VolumeConfig) []VolumePlugin
• type VolumePluginMgr
  • func (pm *VolumePluginMgr) FindCreatablePluginBySpec(spec *Spec) (CreatableVolumePlugin, error)
  • func (pm *VolumePluginMgr) FindDeletablePluginBySpec(spec *Spec) (DeletableVolumePlugin, error)
  • func (pm *VolumePluginMgr) FindPersistentPluginByName(name string) (PersistentVolumePlugin, error)
  • func (pm *VolumePluginMgr) FindPersistentPluginBySpec(spec *Spec) (PersistentVolumePlugin, error)
  • func (pm *VolumePluginMgr) FindPluginByName(name string) (VolumePlugin, error)
  • func (pm *VolumePluginMgr) FindPluginBySpec(spec *Spec) (VolumePlugin, error)
  • func (pm *VolumePluginMgr) FindRecyclablePluginBySpec(spec *Spec) (RecyclableVolumePlugin, error)
  • func (pm *VolumePluginMgr) InitPlugins(plugins []VolumePlugin, host VolumeHost) error

Functions

func CalculateTimeoutForVolume

func CalculateTimeoutForVolume(minimumTimeout, timeoutIncrement int, pv *api.PersistentVolume) int64

CalculateTimeoutForVolume calculates time for a Recycler pod to complete a recycle operation. The calculation and return value is either the minimumTimeout or the timeoutIncrement per Gi of storage size, whichever is greater.

func NewFakeVolumeHost

func NewFakeVolumeHost(rootDir string, kubeClient client.Interface, plugins []VolumePlugin) *fakeVolumeHost

func NewPersistentVolumeRecyclerPodTemplate

func NewPersistentVolumeRecyclerPodTemplate() *api.Pod

NewPersistentVolumeRecyclerPodTemplate creates a template for a recycler pod. By default, a recycler pod simply runs "rm -rf" on a volume and tests for emptiness. Most attributes of the template will be correct for most plugin implementations. The following attributes can be overridden per plugin via configuration:

1. pod.Spec.Volumes[0].VolumeSource must be overridden. Recycler implementations without a valid VolumeSource will fail. 2. pod.GenerateName helps distinguish recycler pods by name. Recommended. Default is "pv-recycler-". 3. pod.Spec.ActiveDeadlineSeconds gives the recycler pod a maximum timeout before failing. Recommended. Default is 60 seconds.

See HostPath and NFS for working recycler examples

func RecycleVolumeByWatchingPodUntilCompletion

func RecycleVolumeByWatchingPodUntilCompletion(pod *api.Pod, kubeClient client.Interface) error

RecycleVolumeByWatchingPodUntilCompletion is intended for use with volume Recyclers. This function will save the given Pod to the API and watch it until it completes, fails, or the pod's ActiveDeadlineSeconds is exceeded, whichever comes first. An attempt to delete a recycler pod is always attempted before returning.

pod - the pod designed by a volume plugin to recycle the volume
client - kube client for API operations.

func RenameDirectory

func RenameDirectory(oldPath, newName string) (string, error)

Types

type Builder

type Builder interface {
	// Uses Interface to provide the path for Docker binds.
	Volume
	// SetUp prepares and mounts/unpacks the volume to a self-determined
	// directory path.  This may be called more than once, so
	// implementations must be idempotent.
	SetUp() error
	// SetUpAt prepares and mounts/unpacks the volume to the specified
	// directory path, which may or may not exist yet.  This may be called
	// more than once, so implementations must be idempotent.
	SetUpAt(dir string) error
	// IsReadOnly is a flag that gives the builder's ReadOnly attribute.
	// All persistent volumes have a private readOnly flag in their builders.
	IsReadOnly() bool
}

Builder interface provides methods to set up/mount the volume.

type Cleaner

type Cleaner interface {
	Volume
	// TearDown unmounts the volume from a self-determined directory and
	// removes traces of the SetUp procedure.
	TearDown() error
	// TearDown unmounts the volume from the specified directory and
	// removes traces of the SetUp procedure.
	TearDownAt(dir string) error
}

Cleaner interface provides methods to cleanup/unmount the volumes.

type CreatableVolumePlugin

type CreatableVolumePlugin interface {
	VolumePlugin
	// NewCreater creates a new volume.Creater which knows how to create PersistentVolumes in accordance with
	// the plugin's underlying storage provider
	NewCreater(options VolumeOptions) (Creater, error)
}

CreatableVolumePlugin is an extended interface of VolumePlugin and is used to create volumes for the cluster.

type Creater

type Creater interface {
	Create() (*api.PersistentVolume, error)
}

Create adds a new resource in the storage provider and creates a PersistentVolume for the new resource. Calls to Create should block until complete.

type DeletableVolumePlugin

type DeletableVolumePlugin interface {
	VolumePlugin
	// NewDeleter creates a new volume.Deleter which knows how to delete this resource
	// in accordance with the underlying storage provider after the volume's release from a claim
	NewDeleter(spec *Spec) (Deleter, error)
}

DeletableVolumePlugin is an extended interface of VolumePlugin and is used by persistent volumes that want to be deleted from the cluster after their release from a PersistentVolumeClaim.

type Deleter

type Deleter interface {
	Volume
	Delete() error
}

Delete removes the resource from the underlying storage provider. Calls to this method should block until the deletion is complete. Any error returned indicates the volume has failed to be reclaimed. A nil return indicates success.

type FakeDeleter

type FakeDeleter struct {
	// contains filtered or unexported fields
}

func (*FakeDeleter) Delete

func (fd *FakeDeleter) Delete() error

func (*FakeDeleter) GetPath

func (fd *FakeDeleter) GetPath() string

type FakeVolume

type FakeVolume struct {
	PodUID  types.UID
	VolName string
	Plugin  *FakeVolumePlugin
}

func (*FakeVolume) GetPath

func (fv *FakeVolume) GetPath() string

func (*FakeVolume) IsReadOnly

func (fv *FakeVolume) IsReadOnly() bool

func (*FakeVolume) SetUp

func (fv *FakeVolume) SetUp() error

func (*FakeVolume) SetUpAt

func (fv *FakeVolume) SetUpAt(dir string) error

func (*FakeVolume) TearDown

func (fv *FakeVolume) TearDown() error

func (*FakeVolume) TearDownAt

func (fv *FakeVolume) TearDownAt(dir string) error

type FakeVolumePlugin

type FakeVolumePlugin struct {
	PluginName string
	Host       VolumeHost
}

FakeVolumePlugin is useful for testing. It tries to be a fully compliant plugin, but all it does is make empty directories. Use as:

volume.RegisterPlugin(&FakePlugin{"fake-name"})

func (*FakeVolumePlugin) CanSupport

func (plugin *FakeVolumePlugin) CanSupport(spec *Spec) bool

func (*FakeVolumePlugin) GetAccessModes

func (plugin *FakeVolumePlugin) GetAccessModes() []api.PersistentVolumeAccessMode

func (*FakeVolumePlugin) Init

func (plugin *FakeVolumePlugin) Init(host VolumeHost)

func (*FakeVolumePlugin) Name

func (plugin *FakeVolumePlugin) Name() string

func (*FakeVolumePlugin) NewBuilder

func (plugin *FakeVolumePlugin) NewBuilder(spec *Spec, pod *api.Pod, opts VolumeOptions) (Builder, error)

func (*FakeVolumePlugin) NewCleaner

func (plugin *FakeVolumePlugin) NewCleaner(volName string, podUID types.UID) (Cleaner, error)

func (*FakeVolumePlugin) NewDeleter

func (plugin *FakeVolumePlugin) NewDeleter(spec *Spec) (Deleter, error)

func (*FakeVolumePlugin) NewRecycler

func (plugin *FakeVolumePlugin) NewRecycler(spec *Spec) (Recycler, error)

type PersistentVolumePlugin

type PersistentVolumePlugin interface {
	VolumePlugin
	// GetAccessModes describes the ways a given volume can be accessed/mounted.
	GetAccessModes() []api.PersistentVolumeAccessMode
}

PersistentVolumePlugin is an extended interface of VolumePlugin and is used by volumes that want to provide long term persistence of data

type RecyclableVolumePlugin

type RecyclableVolumePlugin interface {
	VolumePlugin
	// NewRecycler creates a new volume.Recycler which knows how to reclaim this resource
	// after the volume's release from a PersistentVolumeClaim
	NewRecycler(spec *Spec) (Recycler, error)
}

RecyclableVolumePlugin is an extended interface of VolumePlugin and is used by persistent volumes that want to be recycled before being made available again to new claims

type Recycler

type Recycler interface {
	Volume
	// Recycle reclaims the resource.  Calls to this method should block until the recycling task is complete.
	// Any error returned indicates the volume has failed to be reclaimed.  A nil return indicates success.
	Recycle() error
}

Recycler provides methods to reclaim the volume resource.

func NewFakeRecycler

func NewFakeRecycler(spec *Spec, host VolumeHost, config VolumeConfig) (Recycler, error)

type Spec

type Spec struct {
	Volume           *api.Volume
	PersistentVolume *api.PersistentVolume
	ReadOnly         bool
}

Spec is an internal representation of a volume. All API volume types translate to Spec.

func NewSpecFromPersistentVolume

func NewSpecFromPersistentVolume(pv *api.PersistentVolume, readOnly bool) *Spec

NewSpecFromPersistentVolume creates an Spec from an api.PersistentVolume

func NewSpecFromVolume

func NewSpecFromVolume(vs *api.Volume) *Spec

NewSpecFromVolume creates an Spec from an api.Volume

func (*Spec) Name

func (spec *Spec) Name() string

Name returns the name of either Volume or PersistentVolume, one of which must not be nil.

type Volume

type Volume interface {
	// GetPath returns the directory path the volume is mounted to.
	GetPath() string
}

Volume represents a directory used by pods or hosts on a node. All method implementations of methods in the volume interface must be idempotent.

type VolumeConfig

type VolumeConfig struct {
	// RecyclerPodTemplate is pod template that understands how to scrub clean a persistent volume after its release.
	// The template is used by plugins which override specific properties of the pod in accordance with that plugin.
	// See NewPersistentVolumeRecyclerPodTemplate for the properties that are expected to be overridden.
	RecyclerPodTemplate *api.Pod

	// RecyclerMinimumTimeout is the minimum amount of time in seconds for the recycler pod's ActiveDeadlineSeconds attribute.
	// Added to the minimum timeout is the increment per Gi of capacity.
	RecyclerMinimumTimeout int

	// RecyclerTimeoutIncrement is the number of seconds added to the recycler pod's ActiveDeadlineSeconds for each
	// Gi of capacity in the persistent volume.
	// Example: 5Gi volume x 30s increment = 150s + 30s minimum = 180s ActiveDeadlineSeconds for recycler pod
	RecyclerTimeoutIncrement int

	// OtherAttributes stores config as strings.  These strings are opaque to the system and only understood by the binary
	// hosting the plugin and the plugin itself.
	OtherAttributes map[string]string
}

VolumeConfig is how volume plugins receive configuration. An instance specific to the plugin will be passed to the plugin's ProbeVolumePlugins(config) func. Reasonable defaults will be provided by the binary hosting the plugins while allowing override of those default values. Those config values are then set to an instance of VolumeConfig and passed to the plugin.

Values in VolumeConfig are intended to be relevant to several plugins, but not necessarily all plugins. The preference is to leverage strong typing in this struct. All config items must have a descriptive but non-specific name (i.e, RecyclerMinimumTimeout is OK but RecyclerMinimumTimeoutForNFS is !OK). An instance of config will be given directly to the plugin, so config names specific to plugins are unneeded and wrongly expose plugins in this VolumeConfig struct.

OtherAttributes is a map of string values intended for one-off configuration of a plugin or config that is only relevant to a single plugin. All values are passed by string and require interpretation by the plugin. Passing config as strings is the least desirable option but can be used for truly one-off configuration. The binary should still use strong typing for this value when binding CLI values before they are passed as strings in OtherAttributes.

type VolumeHost

type VolumeHost interface {
	// GetPluginDir returns the absolute path to a directory under which
	// a given plugin may store data.  This directory might not actually
	// exist on disk yet.  For plugin data that is per-pod, see
	// GetPodPluginDir().
	GetPluginDir(pluginName string) string

	// GetPodVolumeDir returns the absolute path a directory which
	// represents the named volume under the named plugin for the given
	// pod.  If the specified pod does not exist, the result of this call
	// might not exist.
	GetPodVolumeDir(podUID types.UID, pluginName string, volumeName string) string

	// GetPodPluginDir returns the absolute path to a directory under which
	// a given plugin may store data for a given pod.  If the specified pod
	// does not exist, the result of this call might not exist.  This
	// directory might not actually exist on disk yet.
	GetPodPluginDir(podUID types.UID, pluginName string) string

	// GetKubeClient returns a client interface
	GetKubeClient() client.Interface

	// NewWrapperBuilder finds an appropriate plugin with which to handle
	// the provided spec.  This is used to implement volume plugins which
	// "wrap" other plugins.  For example, the "secret" volume is
	// implemented in terms of the "emptyDir" volume.
	NewWrapperBuilder(spec *Spec, pod *api.Pod, opts VolumeOptions) (Builder, error)

	// NewWrapperCleaner finds an appropriate plugin with which to handle
	// the provided spec.  See comments on NewWrapperBuilder for more
	// context.
	NewWrapperCleaner(spec *Spec, podUID types.UID) (Cleaner, error)

	// Get cloud provider from kubelet.
	GetCloudProvider() cloudprovider.Interface

	// Get mounter interface.
	GetMounter() mount.Interface

	// Get writer interface for writing data to disk.
	GetWriter() io.Writer
}

VolumeHost is an interface that plugins can use to access the kubelet.

type VolumeOptions

type VolumeOptions struct {
	// The rootcontext to use when performing mounts for a volume.
	// This is a temporary measure in order to set the rootContext of tmpfs mounts correctly.
	// it will be replaced and expanded on by future SecurityContext work.
	RootContext string

	// CapacityMB is the size in MB of a volume.
	CapacityMB int
	// AccessModes of a volume
	AccessModes []api.PersistentVolumeAccessMode
	// Reclamation policy for a persistent volume
	PersistentVolumeReclaimPolicy api.PersistentVolumeReclaimPolicy
}

VolumeOptions contains option information about a volume.

type VolumePlugin

type VolumePlugin interface {
	// Init initializes the plugin.  This will be called exactly once
	// before any New* calls are made - implementations of plugins may
	// depend on this.
	Init(host VolumeHost)

	// Name returns the plugin's name.  Plugins should use namespaced names
	// such as "example.com/volume".  The "kubernetes.io" namespace is
	// reserved for plugins which are bundled with kubernetes.
	Name() string

	// CanSupport tests whether the plugin supports a given volume
	// specification from the API.  The spec pointer should be considered
	// const.
	CanSupport(spec *Spec) bool

	// NewBuilder creates a new volume.Builder from an API specification.
	// Ownership of the spec pointer in *not* transferred.
	// - spec: The api.Volume spec
	// - pod: The enclosing pod
	NewBuilder(spec *Spec, podRef *api.Pod, opts VolumeOptions) (Builder, error)

	// NewCleaner creates a new volume.Cleaner from recoverable state.
	// - name: The volume name, as per the api.Volume spec.
	// - podUID: The UID of the enclosing pod
	NewCleaner(name string, podUID types.UID) (Cleaner, error)
}

VolumePlugin is an interface to volume plugins that can be used on a kubernetes node (e.g. by kubelet) to instantiate and manage volumes.

func ProbeVolumePlugins

func ProbeVolumePlugins(config VolumeConfig) []VolumePlugin

type VolumePluginMgr

type VolumePluginMgr struct {
	// contains filtered or unexported fields
}

VolumePluginMgr tracks registered plugins.

func (*VolumePluginMgr) FindCreatablePluginBySpec

func (pm *VolumePluginMgr) FindCreatablePluginBySpec(spec *Spec) (CreatableVolumePlugin, error)

FindCreatablePluginBySpec fetches a persistent volume plugin by name. If no plugin is found, returns error.

func (*VolumePluginMgr) FindDeletablePluginBySpec

func (pm *VolumePluginMgr) FindDeletablePluginBySpec(spec *Spec) (DeletableVolumePlugin, error)

FindDeletablePluginByName fetches a persistent volume plugin by name. If no plugin is found, returns error.

func (*VolumePluginMgr) FindPersistentPluginByName

func (pm *VolumePluginMgr) FindPersistentPluginByName(name string) (PersistentVolumePlugin, error)

FindPersistentPluginByName fetches a persistent volume plugin by name. If no plugin is found, returns error.

func (*VolumePluginMgr) FindPersistentPluginBySpec

func (pm *VolumePluginMgr) FindPersistentPluginBySpec(spec *Spec) (PersistentVolumePlugin, error)

FindPersistentPluginBySpec looks for a persistent volume plugin that can support a given volume specification. If no plugin is found, return an error

func (*VolumePluginMgr) FindPluginByName

func (pm *VolumePluginMgr) FindPluginByName(name string) (VolumePlugin, error)

FindPluginByName fetches a plugin by name or by legacy name. If no plugin is found, returns error.

func (*VolumePluginMgr) FindPluginBySpec

func (pm *VolumePluginMgr) FindPluginBySpec(spec *Spec) (VolumePlugin, error)

FindPluginBySpec looks for a plugin that can support a given volume specification. If no plugins can support or more than one plugin can support it, return error.

func (*VolumePluginMgr) FindRecyclablePluginBySpec

func (pm *VolumePluginMgr) FindRecyclablePluginBySpec(spec *Spec) (RecyclableVolumePlugin, error)

FindRecyclablePluginByName fetches a persistent volume plugin by name. If no plugin is found, returns error.

func (*VolumePluginMgr) InitPlugins

func (pm *VolumePluginMgr) InitPlugins(plugins []VolumePlugin, host VolumeHost) error

InitPlugins initializes each plugin. All plugins must have unique names. This must be called exactly once before any New* methods are called on any plugins.