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predicates.go
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predicates.go
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/*
Copyright 2014 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package predicates
import (
"errors"
"fmt"
"math/rand"
"strconv"
"sync"
"time"
"github.com/golang/glog"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
utilfeature "k8s.io/apiserver/pkg/util/feature"
"k8s.io/client-go/util/workqueue"
"k8s.io/kubernetes/pkg/api/v1"
v1helper "k8s.io/kubernetes/pkg/api/v1/helper"
v1qos "k8s.io/kubernetes/pkg/api/v1/helper/qos"
corelisters "k8s.io/kubernetes/pkg/client/listers/core/v1"
"k8s.io/kubernetes/pkg/features"
kubeletapis "k8s.io/kubernetes/pkg/kubelet/apis"
volumeutil "k8s.io/kubernetes/pkg/volume/util"
"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
priorityutil "k8s.io/kubernetes/plugin/pkg/scheduler/algorithm/priorities/util"
"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
schedutil "k8s.io/kubernetes/plugin/pkg/scheduler/util"
"k8s.io/metrics/pkg/client/clientset_generated/clientset"
)
// predicatePrecomputations: Helper types/variables...
type PredicateMetadataModifier func(pm *predicateMetadata)
var predicatePrecomputeRegisterLock sync.Mutex
var predicatePrecomputations map[string]PredicateMetadataModifier = make(map[string]PredicateMetadataModifier)
func RegisterPredicatePrecomputation(predicateName string, precomp PredicateMetadataModifier) {
predicatePrecomputeRegisterLock.Lock()
defer predicatePrecomputeRegisterLock.Unlock()
predicatePrecomputations[predicateName] = precomp
}
// Other types for predicate functions...
type NodeInfo interface {
GetNodeInfo(nodeID string) (*v1.Node, error)
}
type PersistentVolumeInfo interface {
GetPersistentVolumeInfo(pvID string) (*v1.PersistentVolume, error)
}
// CachedPersistentVolumeInfo implements PersistentVolumeInfo
type CachedPersistentVolumeInfo struct {
corelisters.PersistentVolumeLister
}
func (c *CachedPersistentVolumeInfo) GetPersistentVolumeInfo(pvID string) (*v1.PersistentVolume, error) {
return c.Get(pvID)
}
type PersistentVolumeClaimInfo interface {
GetPersistentVolumeClaimInfo(namespace string, name string) (*v1.PersistentVolumeClaim, error)
}
// CachedPersistentVolumeClaimInfo implements PersistentVolumeClaimInfo
type CachedPersistentVolumeClaimInfo struct {
corelisters.PersistentVolumeClaimLister
}
// GetPersistentVolumeClaimInfo fetches the claim in specified namespace with specified name
func (c *CachedPersistentVolumeClaimInfo) GetPersistentVolumeClaimInfo(namespace string, name string) (*v1.PersistentVolumeClaim, error) {
return c.PersistentVolumeClaims(namespace).Get(name)
}
type CachedNodeInfo struct {
corelisters.NodeLister
}
// GetNodeInfo returns cached data for the node 'id'.
func (c *CachedNodeInfo) GetNodeInfo(id string) (*v1.Node, error) {
node, err := c.Get(id)
if apierrors.IsNotFound(err) {
return nil, fmt.Errorf("node '%v' not found", id)
}
if err != nil {
return nil, fmt.Errorf("error retrieving node '%v' from cache: %v", id, err)
}
return node, nil
}
// Note that predicateMetadata and matchingPodAntiAffinityTerm need to be declared in the same file
// due to the way declarations are processed in predicate declaration unit tests.
type matchingPodAntiAffinityTerm struct {
term *v1.PodAffinityTerm
node *v1.Node
}
type predicateMetadata struct {
pod *v1.Pod
podBestEffort bool
podRequest *schedulercache.Resource
podPorts map[int]bool
matchingAntiAffinityTerms []matchingPodAntiAffinityTerm
serviceAffinityMatchingPodList []*v1.Pod
serviceAffinityMatchingPodServices []*v1.Service
}
func isVolumeConflict(volume v1.Volume, pod *v1.Pod) bool {
// fast path if there is no conflict checking targets.
if volume.GCEPersistentDisk == nil && volume.AWSElasticBlockStore == nil && volume.RBD == nil && volume.ISCSI == nil {
return false
}
for _, existingVolume := range pod.Spec.Volumes {
// Same GCE disk mounted by multiple pods conflicts unless all pods mount it read-only.
if volume.GCEPersistentDisk != nil && existingVolume.GCEPersistentDisk != nil {
disk, existingDisk := volume.GCEPersistentDisk, existingVolume.GCEPersistentDisk
if disk.PDName == existingDisk.PDName && !(disk.ReadOnly && existingDisk.ReadOnly) {
return true
}
}
if volume.AWSElasticBlockStore != nil && existingVolume.AWSElasticBlockStore != nil {
if volume.AWSElasticBlockStore.VolumeID == existingVolume.AWSElasticBlockStore.VolumeID {
return true
}
}
if volume.ISCSI != nil && existingVolume.ISCSI != nil {
iqn := volume.ISCSI.IQN
eiqn := existingVolume.ISCSI.IQN
// two ISCSI volumes are same, if they share the same iqn. As iscsi volumes are of type
// RWO or ROX, we could permit only one RW mount. Same iscsi volume mounted by multiple Pods
// conflict unless all other pods mount as read only.
if iqn == eiqn && !(volume.ISCSI.ReadOnly && existingVolume.ISCSI.ReadOnly) {
return true
}
}
if volume.RBD != nil && existingVolume.RBD != nil {
mon, pool, image := volume.RBD.CephMonitors, volume.RBD.RBDPool, volume.RBD.RBDImage
emon, epool, eimage := existingVolume.RBD.CephMonitors, existingVolume.RBD.RBDPool, existingVolume.RBD.RBDImage
// two RBDs images are the same if they share the same Ceph monitor, are in the same RADOS Pool, and have the same image name
// only one read-write mount is permitted for the same RBD image.
// same RBD image mounted by multiple Pods conflicts unless all Pods mount the image read-only
if haveSame(mon, emon) && pool == epool && image == eimage && !(volume.RBD.ReadOnly && existingVolume.RBD.ReadOnly) {
return true
}
}
}
return false
}
// NoDiskConflict evaluates if a pod can fit due to the volumes it requests, and those that
// are already mounted. If there is already a volume mounted on that node, another pod that uses the same volume
// can't be scheduled there.
// This is GCE, Amazon EBS, and Ceph RBD specific for now:
// - GCE PD allows multiple mounts as long as they're all read-only
// - AWS EBS forbids any two pods mounting the same volume ID
// - Ceph RBD forbids if any two pods share at least same monitor, and match pool and image.
// - ISCSI forbids if any two pods share at least same IQN, LUN and Target
// TODO: migrate this into some per-volume specific code?
func NoDiskConflict(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
for _, v := range pod.Spec.Volumes {
for _, ev := range nodeInfo.Pods() {
if isVolumeConflict(v, ev) {
return false, []algorithm.PredicateFailureReason{ErrDiskConflict}, nil
}
}
}
return true, nil, nil
}
type MaxPDVolumeCountChecker struct {
filter VolumeFilter
maxVolumes int
pvInfo PersistentVolumeInfo
pvcInfo PersistentVolumeClaimInfo
}
// VolumeFilter contains information on how to filter PD Volumes when checking PD Volume caps
type VolumeFilter struct {
// Filter normal volumes
FilterVolume func(vol *v1.Volume) (id string, relevant bool)
FilterPersistentVolume func(pv *v1.PersistentVolume) (id string, relevant bool)
}
// NewMaxPDVolumeCountPredicate creates a predicate which evaluates whether a pod can fit based on the
// number of volumes which match a filter that it requests, and those that are already present. The
// maximum number is configurable to accommodate different systems.
//
// The predicate looks for both volumes used directly, as well as PVC volumes that are backed by relevant volume
// types, counts the number of unique volumes, and rejects the new pod if it would place the total count over
// the maximum.
func NewMaxPDVolumeCountPredicate(filter VolumeFilter, maxVolumes int, pvInfo PersistentVolumeInfo, pvcInfo PersistentVolumeClaimInfo) algorithm.FitPredicate {
c := &MaxPDVolumeCountChecker{
filter: filter,
maxVolumes: maxVolumes,
pvInfo: pvInfo,
pvcInfo: pvcInfo,
}
return c.predicate
}
func (c *MaxPDVolumeCountChecker) filterVolumes(volumes []v1.Volume, namespace string, filteredVolumes map[string]bool) error {
for i := range volumes {
vol := &volumes[i]
if id, ok := c.filter.FilterVolume(vol); ok {
filteredVolumes[id] = true
} else if vol.PersistentVolumeClaim != nil {
pvcName := vol.PersistentVolumeClaim.ClaimName
if pvcName == "" {
return fmt.Errorf("PersistentVolumeClaim had no name")
}
pvc, err := c.pvcInfo.GetPersistentVolumeClaimInfo(namespace, pvcName)
if err != nil {
// if the PVC is not found, log the error and count the PV towards the PV limit
// generate a random volume ID since its required for de-dup
utilruntime.HandleError(fmt.Errorf("Unable to look up PVC info for %s/%s, assuming PVC matches predicate when counting limits: %v", namespace, pvcName, err))
source := rand.NewSource(time.Now().UnixNano())
generatedID := "missingPVC" + strconv.Itoa(rand.New(source).Intn(1000000))
filteredVolumes[generatedID] = true
return nil
}
if pvc == nil {
return fmt.Errorf("PersistentVolumeClaim not found: %q", pvcName)
}
pvName := pvc.Spec.VolumeName
if pvName == "" {
return fmt.Errorf("PersistentVolumeClaim is not bound: %q", pvcName)
}
pv, err := c.pvInfo.GetPersistentVolumeInfo(pvName)
if err != nil {
// if the PV is not found, log the error
// and count the PV towards the PV limit
// generate a random volume ID since it is required for de-dup
utilruntime.HandleError(fmt.Errorf("Unable to look up PV info for %s/%s/%s, assuming PV matches predicate when counting limits: %v", namespace, pvcName, pvName, err))
source := rand.NewSource(time.Now().UnixNano())
generatedID := "missingPV" + strconv.Itoa(rand.New(source).Intn(1000000))
filteredVolumes[generatedID] = true
return nil
}
if pv == nil {
return fmt.Errorf("PersistentVolume not found: %q", pvName)
}
if id, ok := c.filter.FilterPersistentVolume(pv); ok {
filteredVolumes[id] = true
}
}
}
return nil
}
func (c *MaxPDVolumeCountChecker) predicate(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
// If a pod doesn't have any volume attached to it, the predicate will always be true.
// Thus we make a fast path for it, to avoid unnecessary computations in this case.
if len(pod.Spec.Volumes) == 0 {
return true, nil, nil
}
newVolumes := make(map[string]bool)
if err := c.filterVolumes(pod.Spec.Volumes, pod.Namespace, newVolumes); err != nil {
return false, nil, err
}
// quick return
if len(newVolumes) == 0 {
return true, nil, nil
}
// count unique volumes
existingVolumes := make(map[string]bool)
for _, existingPod := range nodeInfo.Pods() {
if err := c.filterVolumes(existingPod.Spec.Volumes, existingPod.Namespace, existingVolumes); err != nil {
return false, nil, err
}
}
numExistingVolumes := len(existingVolumes)
// filter out already-mounted volumes
for k := range existingVolumes {
if _, ok := newVolumes[k]; ok {
delete(newVolumes, k)
}
}
numNewVolumes := len(newVolumes)
if numExistingVolumes+numNewVolumes > c.maxVolumes {
// violates MaxEBSVolumeCount or MaxGCEPDVolumeCount
return false, []algorithm.PredicateFailureReason{ErrMaxVolumeCountExceeded}, nil
}
return true, nil, nil
}
// EBSVolumeFilter is a VolumeFilter for filtering AWS ElasticBlockStore Volumes
var EBSVolumeFilter VolumeFilter = VolumeFilter{
FilterVolume: func(vol *v1.Volume) (string, bool) {
if vol.AWSElasticBlockStore != nil {
return vol.AWSElasticBlockStore.VolumeID, true
}
return "", false
},
FilterPersistentVolume: func(pv *v1.PersistentVolume) (string, bool) {
if pv.Spec.AWSElasticBlockStore != nil {
return pv.Spec.AWSElasticBlockStore.VolumeID, true
}
return "", false
},
}
// GCEPDVolumeFilter is a VolumeFilter for filtering GCE PersistentDisk Volumes
var GCEPDVolumeFilter VolumeFilter = VolumeFilter{
FilterVolume: func(vol *v1.Volume) (string, bool) {
if vol.GCEPersistentDisk != nil {
return vol.GCEPersistentDisk.PDName, true
}
return "", false
},
FilterPersistentVolume: func(pv *v1.PersistentVolume) (string, bool) {
if pv.Spec.GCEPersistentDisk != nil {
return pv.Spec.GCEPersistentDisk.PDName, true
}
return "", false
},
}
// AzureDiskVolumeFilter is a VolumeFilter for filtering Azure Disk Volumes
var AzureDiskVolumeFilter VolumeFilter = VolumeFilter{
FilterVolume: func(vol *v1.Volume) (string, bool) {
if vol.AzureDisk != nil {
return vol.AzureDisk.DiskName, true
}
return "", false
},
FilterPersistentVolume: func(pv *v1.PersistentVolume) (string, bool) {
if pv.Spec.AzureDisk != nil {
return pv.Spec.AzureDisk.DiskName, true
}
return "", false
},
}
type VolumeZoneChecker struct {
pvInfo PersistentVolumeInfo
pvcInfo PersistentVolumeClaimInfo
}
// VolumeZonePredicate evaluates if a pod can fit due to the volumes it requests, given
// that some volumes may have zone scheduling constraints. The requirement is that any
// volume zone-labels must match the equivalent zone-labels on the node. It is OK for
// the node to have more zone-label constraints (for example, a hypothetical replicated
// volume might allow region-wide access)
//
// Currently this is only supported with PersistentVolumeClaims, and looks to the labels
// only on the bound PersistentVolume.
//
// Working with volumes declared inline in the pod specification (i.e. not
// using a PersistentVolume) is likely to be harder, as it would require
// determining the zone of a volume during scheduling, and that is likely to
// require calling out to the cloud provider. It seems that we are moving away
// from inline volume declarations anyway.
func NewVolumeZonePredicate(pvInfo PersistentVolumeInfo, pvcInfo PersistentVolumeClaimInfo) algorithm.FitPredicate {
c := &VolumeZoneChecker{
pvInfo: pvInfo,
pvcInfo: pvcInfo,
}
return c.predicate
}
func (c *VolumeZoneChecker) predicate(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
// If a pod doesn't have any volume attached to it, the predicate will always be true.
// Thus we make a fast path for it, to avoid unnecessary computations in this case.
if len(pod.Spec.Volumes) == 0 {
return true, nil, nil
}
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
nodeConstraints := make(map[string]string)
for k, v := range node.ObjectMeta.Labels {
if k != kubeletapis.LabelZoneFailureDomain && k != kubeletapis.LabelZoneRegion {
continue
}
nodeConstraints[k] = v
}
if len(nodeConstraints) == 0 {
// The node has no zone constraints, so we're OK to schedule.
// In practice, when using zones, all nodes must be labeled with zone labels.
// We want to fast-path this case though.
return true, nil, nil
}
namespace := pod.Namespace
manifest := &(pod.Spec)
for i := range manifest.Volumes {
volume := &manifest.Volumes[i]
if volume.PersistentVolumeClaim != nil {
pvcName := volume.PersistentVolumeClaim.ClaimName
if pvcName == "" {
return false, nil, fmt.Errorf("PersistentVolumeClaim had no name")
}
pvc, err := c.pvcInfo.GetPersistentVolumeClaimInfo(namespace, pvcName)
if err != nil {
return false, nil, err
}
if pvc == nil {
return false, nil, fmt.Errorf("PersistentVolumeClaim was not found: %q", pvcName)
}
pvName := pvc.Spec.VolumeName
if pvName == "" {
return false, nil, fmt.Errorf("PersistentVolumeClaim is not bound: %q", pvcName)
}
pv, err := c.pvInfo.GetPersistentVolumeInfo(pvName)
if err != nil {
return false, nil, err
}
if pv == nil {
return false, nil, fmt.Errorf("PersistentVolume not found: %q", pvName)
}
for k, v := range pv.ObjectMeta.Labels {
if k != kubeletapis.LabelZoneFailureDomain && k != kubeletapis.LabelZoneRegion {
continue
}
nodeV, _ := nodeConstraints[k]
if v != nodeV {
glog.V(10).Infof("Won't schedule pod %q onto node %q due to volume %q (mismatch on %q)", pod.Name, node.Name, pvName, k)
return false, []algorithm.PredicateFailureReason{ErrVolumeZoneConflict}, nil
}
}
}
}
return true, nil, nil
}
// Returns a *schedulercache.Resource that covers the largest width in each
// resource dimension. Because init-containers run sequentially, we collect the
// max in each dimension iteratively. In contrast, we sum the resource vectors
// for regular containers since they run simultaneously.
//
// Example:
//
// Pod:
// InitContainers
// IC1:
// CPU: 2
// Memory: 1G
// IC2:
// CPU: 2
// Memory: 3G
// Containers
// C1:
// CPU: 2
// Memory: 1G
// C2:
// CPU: 1
// Memory: 1G
//
// Result: CPU: 3, Memory: 3G
func GetResourceRequest(pod *v1.Pod) *schedulercache.Resource {
result := schedulercache.Resource{}
for _, container := range pod.Spec.Containers {
for rName, rQuantity := range container.Resources.Requests {
switch rName {
case v1.ResourceMemory:
result.Memory += rQuantity.Value()
case v1.ResourceCPU:
result.MilliCPU += rQuantity.MilliValue()
case v1.ResourceNvidiaGPU:
result.NvidiaGPU += rQuantity.Value()
case v1.ResourceStorageOverlay:
result.StorageOverlay += rQuantity.Value()
default:
if v1helper.IsOpaqueIntResourceName(rName) {
result.AddOpaque(rName, rQuantity.Value())
}
}
}
}
// Account for storage requested by emptydir volumes
// If the storage medium is memory, should exclude the size
for _, vol := range pod.Spec.Volumes {
if vol.EmptyDir != nil && vol.EmptyDir.Medium != v1.StorageMediumMemory {
result.StorageScratch += vol.EmptyDir.SizeLimit.Value()
}
}
// take max_resource(sum_pod, any_init_container)
for _, container := range pod.Spec.InitContainers {
for rName, rQuantity := range container.Resources.Requests {
switch rName {
case v1.ResourceMemory:
if mem := rQuantity.Value(); mem > result.Memory {
result.Memory = mem
}
case v1.ResourceCPU:
if cpu := rQuantity.MilliValue(); cpu > result.MilliCPU {
result.MilliCPU = cpu
}
case v1.ResourceNvidiaGPU:
if gpu := rQuantity.Value(); gpu > result.NvidiaGPU {
result.NvidiaGPU = gpu
}
case v1.ResourceStorageOverlay:
if overlay := rQuantity.Value(); overlay > result.StorageOverlay {
result.StorageOverlay = overlay
}
default:
if v1helper.IsOpaqueIntResourceName(rName) {
value := rQuantity.Value()
if value > result.OpaqueIntResources[rName] {
result.SetOpaque(rName, value)
}
}
}
}
}
return &result
}
func podName(pod *v1.Pod) string {
return pod.Namespace + "/" + pod.Name
}
func PodFitsResources(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
var predicateFails []algorithm.PredicateFailureReason
allowedPodNumber := nodeInfo.AllowedPodNumber()
if len(nodeInfo.Pods())+1 > allowedPodNumber {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourcePods, 1, int64(len(nodeInfo.Pods())), int64(allowedPodNumber)))
}
var podRequest *schedulercache.Resource
if predicateMeta, ok := meta.(*predicateMetadata); ok {
podRequest = predicateMeta.podRequest
} else {
// We couldn't parse metadata - fallback to computing it.
podRequest = GetResourceRequest(pod)
}
if podRequest.MilliCPU == 0 && podRequest.Memory == 0 && podRequest.NvidiaGPU == 0 && len(podRequest.OpaqueIntResources) == 0 {
return len(predicateFails) == 0, predicateFails, nil
}
allocatable := nodeInfo.AllocatableResource()
if allocatable.MilliCPU < podRequest.MilliCPU+nodeInfo.RequestedResource().MilliCPU {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourceCPU, podRequest.MilliCPU, nodeInfo.RequestedResource().MilliCPU, allocatable.MilliCPU))
}
if allocatable.Memory < podRequest.Memory+nodeInfo.RequestedResource().Memory {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourceMemory, podRequest.Memory, nodeInfo.RequestedResource().Memory, allocatable.Memory))
}
if allocatable.NvidiaGPU < podRequest.NvidiaGPU+nodeInfo.RequestedResource().NvidiaGPU {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourceNvidiaGPU, podRequest.NvidiaGPU, nodeInfo.RequestedResource().NvidiaGPU, allocatable.NvidiaGPU))
}
scratchSpaceRequest := podRequest.StorageScratch
if allocatable.StorageOverlay == 0 {
scratchSpaceRequest += podRequest.StorageOverlay
//scratchSpaceRequest += nodeInfo.RequestedResource().StorageOverlay
nodeScratchRequest := nodeInfo.RequestedResource().StorageOverlay + nodeInfo.RequestedResource().StorageScratch
if allocatable.StorageScratch < scratchSpaceRequest+nodeScratchRequest {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourceStorageScratch, scratchSpaceRequest, nodeScratchRequest, allocatable.StorageScratch))
}
} else if allocatable.StorageScratch < scratchSpaceRequest+nodeInfo.RequestedResource().StorageScratch {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourceStorageScratch, scratchSpaceRequest, nodeInfo.RequestedResource().StorageScratch, allocatable.StorageScratch))
}
if allocatable.StorageOverlay > 0 && allocatable.StorageOverlay < podRequest.StorageOverlay+nodeInfo.RequestedResource().StorageOverlay {
predicateFails = append(predicateFails, NewInsufficientResourceError(v1.ResourceStorageOverlay, podRequest.StorageOverlay, nodeInfo.RequestedResource().StorageOverlay, allocatable.StorageOverlay))
}
for rName, rQuant := range podRequest.OpaqueIntResources {
if allocatable.OpaqueIntResources[rName] < rQuant+nodeInfo.RequestedResource().OpaqueIntResources[rName] {
predicateFails = append(predicateFails, NewInsufficientResourceError(rName, podRequest.OpaqueIntResources[rName], nodeInfo.RequestedResource().OpaqueIntResources[rName], allocatable.OpaqueIntResources[rName]))
}
}
if glog.V(10) && len(predicateFails) == 0 {
// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
// not logged. There is visible performance gain from it.
glog.Infof("Schedule Pod %+v on Node %+v is allowed, Node is running only %v out of %v Pods.",
podName(pod), node.Name, len(nodeInfo.Pods()), allowedPodNumber)
}
return len(predicateFails) == 0, predicateFails, nil
}
// nodeMatchesNodeSelectorTerms checks if a node's labels satisfy a list of node selector terms,
// terms are ORed, and an empty list of terms will match nothing.
func nodeMatchesNodeSelectorTerms(node *v1.Node, nodeSelectorTerms []v1.NodeSelectorTerm) bool {
for _, req := range nodeSelectorTerms {
nodeSelector, err := v1helper.NodeSelectorRequirementsAsSelector(req.MatchExpressions)
if err != nil {
glog.V(10).Infof("Failed to parse MatchExpressions: %+v, regarding as not match.", req.MatchExpressions)
return false
}
if nodeSelector.Matches(labels.Set(node.Labels)) {
return true
}
}
return false
}
// The pod can only schedule onto nodes that satisfy requirements in both NodeAffinity and nodeSelector.
func podMatchesNodeLabels(pod *v1.Pod, node *v1.Node) bool {
// Check if node.Labels match pod.Spec.NodeSelector.
if len(pod.Spec.NodeSelector) > 0 {
selector := labels.SelectorFromSet(pod.Spec.NodeSelector)
if !selector.Matches(labels.Set(node.Labels)) {
return false
}
}
// 1. nil NodeSelector matches all nodes (i.e. does not filter out any nodes)
// 2. nil []NodeSelectorTerm (equivalent to non-nil empty NodeSelector) matches no nodes
// 3. zero-length non-nil []NodeSelectorTerm matches no nodes also, just for simplicity
// 4. nil []NodeSelectorRequirement (equivalent to non-nil empty NodeSelectorTerm) matches no nodes
// 5. zero-length non-nil []NodeSelectorRequirement matches no nodes also, just for simplicity
// 6. non-nil empty NodeSelectorRequirement is not allowed
nodeAffinityMatches := true
affinity := schedulercache.ReconcileAffinity(pod)
if affinity != nil && affinity.NodeAffinity != nil {
nodeAffinity := affinity.NodeAffinity
// if no required NodeAffinity requirements, will do no-op, means select all nodes.
// TODO: Replace next line with subsequent commented-out line when implement RequiredDuringSchedulingRequiredDuringExecution.
if nodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution == nil {
// if nodeAffinity.RequiredDuringSchedulingRequiredDuringExecution == nil && nodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution == nil {
return true
}
// Match node selector for requiredDuringSchedulingRequiredDuringExecution.
// TODO: Uncomment this block when implement RequiredDuringSchedulingRequiredDuringExecution.
// if nodeAffinity.RequiredDuringSchedulingRequiredDuringExecution != nil {
// nodeSelectorTerms := nodeAffinity.RequiredDuringSchedulingRequiredDuringExecution.NodeSelectorTerms
// glog.V(10).Infof("Match for RequiredDuringSchedulingRequiredDuringExecution node selector terms %+v", nodeSelectorTerms)
// nodeAffinityMatches = nodeMatchesNodeSelectorTerms(node, nodeSelectorTerms)
// }
// Match node selector for requiredDuringSchedulingIgnoredDuringExecution.
if nodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution != nil {
nodeSelectorTerms := nodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms
glog.V(10).Infof("Match for RequiredDuringSchedulingIgnoredDuringExecution node selector terms %+v", nodeSelectorTerms)
nodeAffinityMatches = nodeAffinityMatches && nodeMatchesNodeSelectorTerms(node, nodeSelectorTerms)
}
}
return nodeAffinityMatches
}
func PodMatchNodeSelector(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
if podMatchesNodeLabels(pod, node) {
return true, nil, nil
}
return false, []algorithm.PredicateFailureReason{ErrNodeSelectorNotMatch}, nil
}
func PodFitsHost(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
if len(pod.Spec.NodeName) == 0 {
return true, nil, nil
}
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
if pod.Spec.NodeName == node.Name {
return true, nil, nil
}
return false, []algorithm.PredicateFailureReason{ErrPodNotMatchHostName}, nil
}
type NodeLabelChecker struct {
labels []string
presence bool
}
func NewNodeLabelPredicate(labels []string, presence bool) algorithm.FitPredicate {
labelChecker := &NodeLabelChecker{
labels: labels,
presence: presence,
}
return labelChecker.CheckNodeLabelPresence
}
// CheckNodeLabelPresence checks whether all of the specified labels exists on a node or not, regardless of their value
// If "presence" is false, then returns false if any of the requested labels matches any of the node's labels,
// otherwise returns true.
// If "presence" is true, then returns false if any of the requested labels does not match any of the node's labels,
// otherwise returns true.
//
// Consider the cases where the nodes are placed in regions/zones/racks and these are identified by labels
// In some cases, it is required that only nodes that are part of ANY of the defined regions/zones/racks be selected
//
// Alternately, eliminating nodes that have a certain label, regardless of value, is also useful
// A node may have a label with "retiring" as key and the date as the value
// and it may be desirable to avoid scheduling new pods on this node
func (n *NodeLabelChecker) CheckNodeLabelPresence(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
var exists bool
nodeLabels := labels.Set(node.Labels)
for _, label := range n.labels {
exists = nodeLabels.Has(label)
if (exists && !n.presence) || (!exists && n.presence) {
return false, []algorithm.PredicateFailureReason{ErrNodeLabelPresenceViolated}, nil
}
}
return true, nil, nil
}
type ServiceAffinity struct {
podLister algorithm.PodLister
serviceLister algorithm.ServiceLister
nodeInfo NodeInfo
labels []string
}
// serviceAffinityPrecomputation should be run once by the scheduler before looping through the Predicate. It is a helper function that
// only should be referenced by NewServiceAffinityPredicate.
func (s *ServiceAffinity) serviceAffinityPrecomputation(pm *predicateMetadata) {
if pm.pod == nil {
glog.Errorf("Cannot precompute service affinity, a pod is required to calculate service affinity.")
return
}
var errSvc, errList error
// Store services which match the pod.
pm.serviceAffinityMatchingPodServices, errSvc = s.serviceLister.GetPodServices(pm.pod)
selector := CreateSelectorFromLabels(pm.pod.Labels)
// consider only the pods that belong to the same namespace
allMatches, errList := s.podLister.List(selector)
// In the future maybe we will return them as part of the function.
if errSvc != nil || errList != nil {
glog.Errorf("Some Error were found while precomputing svc affinity: \nservices:%v , \npods:%v", errSvc, errList)
}
pm.serviceAffinityMatchingPodList = FilterPodsByNamespace(allMatches, pm.pod.Namespace)
}
func NewServiceAffinityPredicate(podLister algorithm.PodLister, serviceLister algorithm.ServiceLister, nodeInfo NodeInfo, labels []string) (algorithm.FitPredicate, PredicateMetadataModifier) {
affinity := &ServiceAffinity{
podLister: podLister,
serviceLister: serviceLister,
nodeInfo: nodeInfo,
labels: labels,
}
return affinity.checkServiceAffinity, affinity.serviceAffinityPrecomputation
}
// checkServiceAffinity is a predicate which matches nodes in such a way to force that
// ServiceAffinity.labels are homogenous for pods that are scheduled to a node.
// (i.e. it returns true IFF this pod can be added to this node such that all other pods in
// the same service are running on nodes with
// the exact same ServiceAffinity.label values).
//
// For example:
// If the first pod of a service was scheduled to a node with label "region=foo",
// all the other subsequent pods belong to the same service will be schedule on
// nodes with the same "region=foo" label.
//
// Details:
//
// If (the svc affinity labels are not a subset of pod's label selectors )
// The pod has all information necessary to check affinity, the pod's label selector is sufficient to calculate
// the match.
// Otherwise:
// Create an "implicit selector" which guarantees pods will land on nodes with similar values
// for the affinity labels.
//
// To do this, we "reverse engineer" a selector by introspecting existing pods running under the same service+namespace.
// These backfilled labels in the selector "L" are defined like so:
// - L is a label that the ServiceAffinity object needs as a matching constraints.
// - L is not defined in the pod itself already.
// - and SOME pod, from a service, in the same namespace, ALREADY scheduled onto a node, has a matching value.
//
// WARNING: This Predicate is NOT guaranteed to work if some of the predicateMetadata data isn't precomputed...
// For that reason it is not exported, i.e. it is highly coupled to the implementation of the FitPredicate construction.
func (s *ServiceAffinity) checkServiceAffinity(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
var services []*v1.Service
var pods []*v1.Pod
if pm, ok := meta.(*predicateMetadata); ok && (pm.serviceAffinityMatchingPodList != nil || pm.serviceAffinityMatchingPodServices != nil) {
services = pm.serviceAffinityMatchingPodServices
pods = pm.serviceAffinityMatchingPodList
} else {
// Make the predicate resilient in case metadata is missing.
pm = &predicateMetadata{pod: pod}
s.serviceAffinityPrecomputation(pm)
pods, services = pm.serviceAffinityMatchingPodList, pm.serviceAffinityMatchingPodServices
}
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
// check if the pod being scheduled has the affinity labels specified in its NodeSelector
affinityLabels := FindLabelsInSet(s.labels, labels.Set(pod.Spec.NodeSelector))
// Step 1: If we don't have all constraints, introspect nodes to find the missing constraints.
if len(s.labels) > len(affinityLabels) {
if len(services) > 0 {
if len(pods) > 0 {
nodeWithAffinityLabels, err := s.nodeInfo.GetNodeInfo(pods[0].Spec.NodeName)
if err != nil {
return false, nil, err
}
AddUnsetLabelsToMap(affinityLabels, s.labels, labels.Set(nodeWithAffinityLabels.Labels))
}
}
}
// Step 2: Finally complete the affinity predicate based on whatever set of predicates we were able to find.
if CreateSelectorFromLabels(affinityLabels).Matches(labels.Set(node.Labels)) {
return true, nil, nil
}
return false, []algorithm.PredicateFailureReason{ErrServiceAffinityViolated}, nil
}
func PodFitsHostPorts(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
var wantPorts map[int]bool
if predicateMeta, ok := meta.(*predicateMetadata); ok {
wantPorts = predicateMeta.podPorts
} else {
// We couldn't parse metadata - fallback to computing it.
wantPorts = schedutil.GetUsedPorts(pod)
}
if len(wantPorts) == 0 {
return true, nil, nil
}
existingPorts := nodeInfo.UsedPorts()
for wport := range wantPorts {
if wport != 0 && existingPorts[wport] {
return false, []algorithm.PredicateFailureReason{ErrPodNotFitsHostPorts}, nil
}
}
return true, nil, nil
}
// search two arrays and return true if they have at least one common element; return false otherwise
func haveSame(a1, a2 []string) bool {
for _, val1 := range a1 {
for _, val2 := range a2 {
if val1 == val2 {
return true
}
}
}
return false
}
func GeneralPredicates(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
var predicateFails []algorithm.PredicateFailureReason
fit, reasons, err := noncriticalPredicates(pod, meta, nodeInfo)
if err != nil {
return false, predicateFails, err
}
if !fit {
predicateFails = append(predicateFails, reasons...)
}
fit, reasons, err = EssentialPredicates(pod, meta, nodeInfo)
if err != nil {
return false, predicateFails, err
}
if !fit {
predicateFails = append(predicateFails, reasons...)
}
return len(predicateFails) == 0, predicateFails, nil
}
// noncriticalPredicates are the predicates that only non-critical pods need
func noncriticalPredicates(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
var predicateFails []algorithm.PredicateFailureReason
fit, reasons, err := PodFitsResources(pod, meta, nodeInfo)
if err != nil {
return false, predicateFails, err
}
if !fit {
predicateFails = append(predicateFails, reasons...)
}
return len(predicateFails) == 0, predicateFails, nil
}
// EssentialPredicates are the predicates that all pods, including critical pods, need
func EssentialPredicates(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
var predicateFails []algorithm.PredicateFailureReason
fit, reasons, err := PodFitsHost(pod, meta, nodeInfo)
if err != nil {
return false, predicateFails, err
}
if !fit {
predicateFails = append(predicateFails, reasons...)
}
// TODO: PodFitsHostPorts is essential for now, but kubelet should ideally
// preempt pods to free up host ports too
fit, reasons, err = PodFitsHostPorts(pod, meta, nodeInfo)
if err != nil {
return false, predicateFails, err
}
if !fit {
predicateFails = append(predicateFails, reasons...)
}
fit, reasons, err = PodMatchNodeSelector(pod, meta, nodeInfo)
if err != nil {
return false, predicateFails, err
}
if !fit {
predicateFails = append(predicateFails, reasons...)
}
return len(predicateFails) == 0, predicateFails, nil
}
type PodAffinityChecker struct {
info NodeInfo
podLister algorithm.PodLister
}
func NewPodAffinityPredicate(info NodeInfo, podLister algorithm.PodLister) algorithm.FitPredicate {
checker := &PodAffinityChecker{
info: info,
podLister: podLister,
}
return checker.InterPodAffinityMatches
}
func (c *PodAffinityChecker) InterPodAffinityMatches(pod *v1.Pod, meta interface{}, nodeInfo *schedulercache.NodeInfo) (bool, []algorithm.PredicateFailureReason, error) {
node := nodeInfo.Node()
if node == nil {
return false, nil, fmt.Errorf("node not found")
}
if !c.satisfiesExistingPodsAntiAffinity(pod, meta, node) {
return false, []algorithm.PredicateFailureReason{ErrPodAffinityNotMatch}, nil
}
// Now check if <pod> requirements will be satisfied on this node.
affinity := schedulercache.ReconcileAffinity(pod)
if affinity == nil || (affinity.PodAffinity == nil && affinity.PodAntiAffinity == nil) {
return true, nil, nil
}
if !c.satisfiesPodsAffinityAntiAffinity(pod, node, affinity) {
return false, []algorithm.PredicateFailureReason{ErrPodAffinityNotMatch}, nil
}
if glog.V(10) {
// We explicitly don't do glog.V(10).Infof() to avoid computing all the parameters if this is
// not logged. There is visible performance gain from it.
glog.Infof("Schedule Pod %+v on Node %+v is allowed, pod (anti)affinity constraints satisfied",
podName(pod), node.Name)