/* Copyright 2019 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 podtopologyspread import ( "fmt" v1 "k8s.io/api/core/v1" "k8s.io/apimachinery/pkg/runtime" "k8s.io/client-go/informers" appslisters "k8s.io/client-go/listers/apps/v1" corelisters "k8s.io/client-go/listers/core/v1" "k8s.io/kubernetes/pkg/scheduler/apis/config" "k8s.io/kubernetes/pkg/scheduler/apis/config/validation" "k8s.io/kubernetes/pkg/scheduler/framework" "k8s.io/kubernetes/pkg/scheduler/internal/parallelize" ) const ( // ErrReasonConstraintsNotMatch is used for PodTopologySpread filter error. ErrReasonConstraintsNotMatch = "node(s) didn't match pod topology spread constraints" // ErrReasonNodeLabelNotMatch is used when the node doesn't hold the required label. ErrReasonNodeLabelNotMatch = ErrReasonConstraintsNotMatch + " (missing required label)" ) var systemDefaultConstraints = []v1.TopologySpreadConstraint{ { TopologyKey: v1.LabelHostname, WhenUnsatisfiable: v1.ScheduleAnyway, MaxSkew: 3, }, { TopologyKey: v1.LabelTopologyZone, WhenUnsatisfiable: v1.ScheduleAnyway, MaxSkew: 5, }, } // PodTopologySpread is a plugin that ensures pod's topologySpreadConstraints is satisfied. type PodTopologySpread struct { parallelizer parallelize.Parallelizer defaultConstraints []v1.TopologySpreadConstraint sharedLister framework.SharedLister services corelisters.ServiceLister replicationCtrls corelisters.ReplicationControllerLister replicaSets appslisters.ReplicaSetLister statefulSets appslisters.StatefulSetLister } var _ framework.PreFilterPlugin = &PodTopologySpread{} var _ framework.FilterPlugin = &PodTopologySpread{} var _ framework.PreScorePlugin = &PodTopologySpread{} var _ framework.ScorePlugin = &PodTopologySpread{} const ( // Name is the name of the plugin used in the plugin registry and configurations. Name = "PodTopologySpread" ) // Name returns name of the plugin. It is used in logs, etc. func (pl *PodTopologySpread) Name() string { return Name } // New initializes a new plugin and returns it. func New(plArgs runtime.Object, h framework.Handle) (framework.Plugin, error) { if h.SnapshotSharedLister() == nil { return nil, fmt.Errorf("SnapshotSharedlister is nil") } args, err := getArgs(plArgs) if err != nil { return nil, err } if err := validation.ValidatePodTopologySpreadArgs(&args); err != nil { return nil, err } pl := &PodTopologySpread{ parallelizer: h.Parallelizer(), sharedLister: h.SnapshotSharedLister(), defaultConstraints: args.DefaultConstraints, } if args.DefaultingType == config.SystemDefaulting { pl.defaultConstraints = systemDefaultConstraints } if len(pl.defaultConstraints) != 0 { if h.SharedInformerFactory() == nil { return nil, fmt.Errorf("SharedInformerFactory is nil") } pl.setListers(h.SharedInformerFactory()) } return pl, nil } func getArgs(obj runtime.Object) (config.PodTopologySpreadArgs, error) { ptr, ok := obj.(*config.PodTopologySpreadArgs) if !ok { return config.PodTopologySpreadArgs{}, fmt.Errorf("want args to be of type PodTopologySpreadArgs, got %T", obj) } return *ptr, nil } func (pl *PodTopologySpread) setListers(factory informers.SharedInformerFactory) { pl.services = factory.Core().V1().Services().Lister() pl.replicationCtrls = factory.Core().V1().ReplicationControllers().Lister() pl.replicaSets = factory.Apps().V1().ReplicaSets().Lister() pl.statefulSets = factory.Apps().V1().StatefulSets().Lister() }