implement taints and tolerations

plugin/pkg/scheduler/algorithm/priorities/taint_toleration.go

@@ -0,0 +1,110 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 priorities
+
+import (
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
+	schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
+	"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
+)
+
+// NodeTaints hold the node lister
+type TaintToleration struct {
+	nodeLister algorithm.NodeLister
+}
+
+// NewTaintTolerationPriority
+func NewTaintTolerationPriority(nodeLister algorithm.NodeLister) algorithm.PriorityFunction {
+	taintToleration := &TaintToleration{
+		nodeLister: nodeLister,
+	}
+	return taintToleration.ComputeTaintTolerationPriority
+}
+
+// CountIntolerableTaintsPreferNoSchedule gives the count of intolerable taints of a pod with effect PreferNoSchedule
+func countIntolerableTaintsPreferNoSchedule(taints []api.Taint, tolerations []api.Toleration) (intolerableTaints int) {
+	for _, taint := range taints {
+		// check only on taints that have effect PreferNoSchedule
+		if taint.Effect != api.TaintEffectPreferNoSchedule {
+			continue
+		}
+
+		if !api.TaintToleratedByTolerations(taint, tolerations) {
+			intolerableTaints++
+		}
+	}
+	return
+}
+
+// getAllTolerationEffectPreferNoSchedule gets the list of all Toleration with Effect PreferNoSchedule
+func getAllTolerationPreferNoSchedule(tolerations []api.Toleration) (tolerationList []api.Toleration) {
+	for _, toleration := range tolerations {
+		if len(toleration.Effect) == 0 || toleration.Effect == api.TaintEffectPreferNoSchedule {
+			tolerationList = append(tolerationList, toleration)
+		}
+	}
+	return
+}
+
+// ComputeTaintTolerationPriority prepares the priority list for all the nodes based on the number of intolerable taints on the node
+func (s *TaintToleration) ComputeTaintTolerationPriority(pod *api.Pod, nodeNameToInfo map[string]*schedulercache.NodeInfo, nodeLister algorithm.NodeLister) (schedulerapi.HostPriorityList, error) {
+	// counts hold the count of intolerable taints of a pod for a given node
+	counts := make(map[string]int)
+
+	// the max value of counts
+	var maxCount int
+
+	nodes, err := nodeLister.List()
+	if err != nil {
+		return nil, err
+	}
+
+	tolerations, err := api.GetTolerationsFromPodAnnotations(pod.Annotations)
+	if err != nil {
+		return nil, err
+	}
+	// Fetch a list of all toleration with effect PreferNoSchedule
+	tolerationList := getAllTolerationPreferNoSchedule(tolerations)
+
+	// calculate the intolerable taints for all the nodes
+	for _, node := range nodes.Items {
+		taints, err := api.GetTaintsFromNodeAnnotations(node.Annotations)
+		if err != nil {
+			return nil, err
+		}
+
+		count := countIntolerableTaintsPreferNoSchedule(taints, tolerationList)
+		counts[node.Name] = count
+		if count > maxCount {
+			maxCount = count
+		}
+	}
+
+	// The maximum priority value to give to a node
+	// Priority values range from 0 - maxPriority
+	const maxPriority = 10
+	result := []schedulerapi.HostPriority{}
+	for _, node := range nodes.Items {
+		fScore := float64(maxPriority)
+		if maxCount > 0 {
+			fScore = (1.0 - float64(counts[node.Name])/float64(maxCount)) * 10
+		}
+		result = append(result, schedulerapi.HostPriority{Host: node.Name, Score: int(fScore)})
+	}
+	return result, nil
+}