cache

package
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 Go to latest Published: Sep 24, 2019 License: Apache-2.0 Imports: 16 Imported by: 0

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Constants

This section is empty.

Variables

This section is empty.

Functions

func CreateNodeNameToInfoMap 

func CreateNodeNameToInfoMap(pods []*v1.Pod, nodes []*v1.Node) map[string]*NodeInfo

CreateNodeNameToInfoMap obtains a list of pods and pivots that list into a map where the keys are node names and the values are the aggregated information for that node.

Types

type Cache 

type Cache interface {
	// AssumePod assumes a pod scheduled and aggregates the pod's information into its node.
	// The implementation also decides the policy to expire pod before being confirmed (receiving Add event).
	// After expiration, its information would be subtracted.
	AssumePod(pod *v1.Pod) error

	// FinishBinding signals that cache for assumed pod can be expired
	FinishBinding(pod *v1.Pod) error

	// ForgetPod removes an assumed pod from cache.
	ForgetPod(pod *v1.Pod) error

	// AddPod either confirms a pod if it's assumed, or adds it back if it's expired.
	// If added back, the pod's information would be added again.
	AddPod(pod *v1.Pod) error

	// UpdatePod removes oldPod's information and adds newPod's information.
	UpdatePod(oldPod, newPod *v1.Pod) error

	// RemovePod removes a pod. The pod's information would be subtracted from assigned node.
	RemovePod(pod *v1.Pod) error

	// GetPod returns the pod from the cache with the same namespace and the
	// same name of the specified pod.
	GetPod(pod *v1.Pod) (*v1.Pod, error)

	// IsAssumedPod returns true if the pod is assumed and not expired.
	IsAssumedPod(pod *v1.Pod) (bool, error)

	// AddNode adds overall information about node.
	AddNode(node *v1.Node) error

	// UpdateNode updates overall information about node.
	UpdateNode(oldNode, newNode *v1.Node) error

	// RemoveNode removes overall information about node.
	RemoveNode(node *v1.Node) error

	// AddPDB adds a PodDisruptionBudget object to the cache.
	AddPDB(pdb *policy.PodDisruptionBudget) error

	// UpdatePDB updates a PodDisruptionBudget object in the cache.
	UpdatePDB(oldPDB, newPDB *policy.PodDisruptionBudget) error

	// RemovePDB removes a PodDisruptionBudget object from the cache.
	RemovePDB(pdb *policy.PodDisruptionBudget) error

	// List lists all cached PDBs matching the selector.
	ListPDBs(selector labels.Selector) ([]*policy.PodDisruptionBudget, error)

	// UpdateNodeNameToInfoMap updates the passed infoMap to the current contents of Cache.
	// The node info contains aggregated information of pods scheduled (including assumed to be)
	// on this node.
	UpdateNodeNameToInfoMap(infoMap map[string]*NodeInfo) error

	// List lists all cached pods (including assumed ones).
	List(labels.Selector) ([]*v1.Pod, error)

	// FilteredList returns all cached pods that pass the filter.
	FilteredList(filter PodFilter, selector labels.Selector) ([]*v1.Pod, error)

	// Snapshot takes a snapshot on current cache
	Snapshot() *Snapshot

	// IsUpToDate returns true if the given NodeInfo matches the current data in the cache.
	IsUpToDate(n *NodeInfo) bool
}

Cache collects pods' information and provides node-level aggregated information. It's intended for generic scheduler to do efficient lookup. Cache's operations are pod centric. It does incremental updates based on pod events. Pod events are sent via network. We don't have guaranteed delivery of all events: We use Reflector to list and watch from remote. Reflector might be slow and do a relist, which would lead to missing events.

State Machine of a pod's events in scheduler's cache: 

+-------------------------------------------+  +----+
|                            Add            |  |    |
|                                           |  |    | Update
+      Assume                Add            v  v    |

Initial +--------> Assumed +------------+---> Added <--+ 

^                +   +               |       +
|                |   |               |       |
|                |   |           Add |       | Remove
|                |   |               |       |
|                |   |               +       |
+----------------+   +-----------> Expired   +----> Deleted
      Forget             Expire

Note that an assumed pod can expire, because if we haven't received Add event notifying us for a while, there might be some problems and we shouldn't keep the pod in cache anymore.

Note that "Initial", "Expired", and "Deleted" pods do not actually exist in cache. Based on existing use cases, we are making the following assumptions:

  • No pod would be assumed twice
  • A pod could be added without going through scheduler. In this case, we will see Add but not Assume event.
  • If a pod wasn't added, it wouldn't be removed or updated.
  • Both "Expired" and "Deleted" are valid end states. In case of some problems, e.g. network issue, a pod might have changed its state (e.g. added and deleted) without delivering notification to the cache.

func New 

func New(ttl time.Duration, stop <-chan struct{}) Cache

New returns a Cache implementation. It automatically starts a go routine that manages expiration of assumed pods. "ttl" is how long the assumed pod will get expired. "stop" is the channel that would close the background goroutine.

type NodeInfo 

type NodeInfo struct {

	// TransientInfo holds the information pertaining to a scheduling cycle. This will be destructed at the end of
	// scheduling cycle.
	// TODO: @ravig. Remove this once we have a clear approach for message passing across predicates and priorities.
	TransientInfo *transientSchedulerInfo
	// contains filtered or unexported fields
}

NodeInfo is node level aggregated information.

func NewNodeInfo 

func NewNodeInfo(pods ...*v1.Pod) *NodeInfo

NewNodeInfo returns a ready to use empty NodeInfo object. If any pods are given in arguments, their information will be aggregated in the returned object.

func (*NodeInfo) AddPod 

func (n *NodeInfo) AddPod(pod *v1.Pod)

AddPod adds pod information to this NodeInfo.

func (*NodeInfo) AllocatableResource 

func (n *NodeInfo) AllocatableResource() Resource

AllocatableResource returns allocatable resources on a given node.

func (*NodeInfo) AllowedPodNumber 

func (n *NodeInfo) AllowedPodNumber() int

AllowedPodNumber returns the number of the allowed pods on this node.

func (*NodeInfo) Clone 

func (n *NodeInfo) Clone() *NodeInfo

Clone returns a copy of this node.

func (*NodeInfo) DiskPressureCondition 

func (n *NodeInfo) DiskPressureCondition() v1.ConditionStatus

DiskPressureCondition returns the disk pressure condition status on this node.

func (*NodeInfo) Filter 

func (n *NodeInfo) Filter(pod *v1.Pod) bool

Filter implements PodFilter interface. It returns false only if the pod node name matches NodeInfo.node and the pod is not found in the pods list. Otherwise, returns true.

func (*NodeInfo) FilterOutPods 

func (n *NodeInfo) FilterOutPods(pods []*v1.Pod) []*v1.Pod

FilterOutPods receives a list of pods and filters out those whose node names are equal to the node of this NodeInfo, but are not found in the pods of this NodeInfo.

Preemption logic simulates removal of pods on a node by removing them from the corresponding NodeInfo. In order for the simulation to work, we call this method on the pods returned from SchedulerCache, so that predicate functions see only the pods that are not removed from the NodeInfo.

func (*NodeInfo) ImageSizes 

func (n *NodeInfo) ImageSizes() map[string]int64

ImageSizes returns the image size information on this node.

func (*NodeInfo) MemoryPressureCondition 

func (n *NodeInfo) MemoryPressureCondition() v1.ConditionStatus

MemoryPressureCondition returns the memory pressure condition status on this node.

func (*NodeInfo) Node 

func (n *NodeInfo) Node() *v1.Node

Node returns overall information about this node.

func (*NodeInfo) NonZeroRequest 

func (n *NodeInfo) NonZeroRequest() Resource

NonZeroRequest returns aggregated nonzero resource request of pods on this node.

func (*NodeInfo) PIDPressureCondition 

func (n *NodeInfo) PIDPressureCondition() v1.ConditionStatus

PIDPressureCondition returns the pid pressure condition status on this node.

func (*NodeInfo) Pods 

func (n *NodeInfo) Pods() []*v1.Pod

Pods return all pods scheduled (including assumed to be) on this node.

func (*NodeInfo) PodsWithAffinity 

func (n *NodeInfo) PodsWithAffinity() []*v1.Pod

PodsWithAffinity return all pods with (anti)affinity constraints on this node.

func (*NodeInfo) RemoveNode 

func (n *NodeInfo) RemoveNode(node *v1.Node) error

RemoveNode removes the overall information about the node.

func (*NodeInfo) RemovePod 

func (n *NodeInfo) RemovePod(pod *v1.Pod) error

RemovePod subtracts pod information from this NodeInfo.

func (*NodeInfo) RequestedResource 

func (n *NodeInfo) RequestedResource() Resource

RequestedResource returns aggregated resource request of pods on this node.

func (*NodeInfo) SetAllocatableResource 

func (n *NodeInfo) SetAllocatableResource(allocatableResource *Resource)

SetAllocatableResource sets the allocatableResource information of given node.

func (*NodeInfo) SetNode 

func (n *NodeInfo) SetNode(node *v1.Node) error

SetNode sets the overall node information.

func (*NodeInfo) String 

func (n *NodeInfo) String() string

String returns representation of human readable format of this NodeInfo.

func (*NodeInfo) Taints 

func (n *NodeInfo) Taints() ([]v1.Taint, error)

Taints returns the taints list on this node.

func (*NodeInfo) UsedPorts 

func (n *NodeInfo) UsedPorts() util.HostPortInfo

UsedPorts returns used ports on this node.

func (*NodeInfo) VolumeLimits 

func (n *NodeInfo) VolumeLimits() map[v1.ResourceName]int64

VolumeLimits returns volume limits associated with the node

type PodFilter 

type PodFilter func(*v1.Pod) bool

PodFilter is a function to filter a pod. If pod passed return true else return false.

type Resource 

type Resource struct {
	MilliCPU         int64
	Memory           int64
	EphemeralStorage int64
	// We store allowedPodNumber (which is Node.Status.Allocatable.Pods().Value())
	// explicitly as int, to avoid conversions and improve performance.
	AllowedPodNumber int
	// ScalarResources
	ScalarResources map[v1.ResourceName]int64
}

Resource is a collection of compute resource.

func NewResource 

func NewResource(rl v1.ResourceList) *Resource

NewResource creates a Resource from ResourceList

func (*Resource) Add 

func (r *Resource) Add(rl v1.ResourceList)

Add adds ResourceList into Resource.

func (*Resource) AddScalar 

func (r *Resource) AddScalar(name v1.ResourceName, quantity int64)

AddScalar adds a resource by a scalar value of this resource.

func (*Resource) Clone 

func (r *Resource) Clone() *Resource

Clone returns a copy of this resource.

func (*Resource) ResourceList 

func (r *Resource) ResourceList() v1.ResourceList

ResourceList returns a resource list of this resource.

func (*Resource) SetMaxResource 

func (r *Resource) SetMaxResource(rl v1.ResourceList)

SetMaxResource compares with ResourceList and takes max value for each Resource.

func (*Resource) SetScalar 

func (r *Resource) SetScalar(name v1.ResourceName, quantity int64)

SetScalar sets a resource by a scalar value of this resource.

type Snapshot 

type Snapshot struct {
	AssumedPods map[string]bool
	Nodes       map[string]*NodeInfo
	Pdbs        map[string]*policy.PodDisruptionBudget
}

Snapshot is a snapshot of cache state

Source Files

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