Adding label checker predicates and test cases

pkg/scheduler/predicates.go

@@ -167,6 +167,43 @@ func PodFitsHost(pod api.Pod, existingPods []api.Pod, node string) (bool, error)
 	return pod.Spec.Host == node, nil
 }
 
+type NodeLabelChecker struct {
+	info     NodeInfo
+	labels   []string
+	presence bool
+}
+
+func NewNodeLabelPredicate(info NodeInfo, labels []string, presence bool) FitPredicate {
+	labelChecker := &NodeLabelChecker{
+		info:     info,
+		labels:   labels,
+		presence: presence,
+	}
+	return labelChecker.CheckNodeLabelPresence
+}
+
+// CheckNodeLabelPresence checks whether a particular label exists on a minion or not, regardless of its value
+// Consider the cases where the minions are places in regions/zones/racks and these are identified by labels
+// In some cases, it is required that only minions that are part of ANY of the defined regions/zones/racks be selected
+//
+// Alternately, eliminating minions that have a certain label, regardless of value, is also useful
+// A minion 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 minion
+func (n *NodeLabelChecker) CheckNodeLabelPresence(pod api.Pod, existingPods []api.Pod, node string) (bool, error) {
+	var exists bool
+	minion, err := n.info.GetNodeInfo(node)
+	if err != nil {
+		return false, err
+	}
+	for _, label := range n.labels {
+		exists = labels.Set(minion.Labels).Has(label)
+		if (exists && !n.presence) || (!exists && n.presence) {
+			return false, nil
+		}
+	}
+	return true, nil
+}
+
 func PodFitsPorts(pod api.Pod, existingPods []api.Pod, node string) (bool, error) {
 	existingPorts := getUsedPorts(existingPods...)
 	wantPorts := getUsedPorts(pod)

pkg/scheduler/predicates_test.go

@@ -386,3 +386,63 @@ func TestPodFitsSelector(t *testing.T) {
 		}
 	}
 }
+
+func TestNodeLabelPresence(t *testing.T) {
+	label := map[string]string{"foo": "bar", "bar": "foo"}
+	tests := []struct {
+		pod          api.Pod
+		existingPods []api.Pod
+		labels       []string
+		presence     bool
+		fits         bool
+		test         string
+	}{
+		{
+			labels:   []string{"baz"},
+			presence: true,
+			fits:     false,
+			test:     "label does not match, presence true",
+		},
+		{
+			labels:   []string{"baz"},
+			presence: false,
+			fits:     true,
+			test:     "label does not match, presence false",
+		},
+		{
+			labels:   []string{"foo", "baz"},
+			presence: true,
+			fits:     false,
+			test:     "one label matches, presence true",
+		},
+		{
+			labels:   []string{"foo", "baz"},
+			presence: false,
+			fits:     false,
+			test:     "one label matches, presence false",
+		},
+		{
+			labels:   []string{"foo", "bar"},
+			presence: true,
+			fits:     true,
+			test:     "all labels match, presence true",
+		},
+		{
+			labels:   []string{"foo", "bar"},
+			presence: false,
+			fits:     false,
+			test:     "all labels match, presence false",
+		},
+	}
+	for _, test := range tests {
+		node := api.Node{ObjectMeta: api.ObjectMeta{Labels: label}}
+		labelChecker := NodeLabelChecker{FakeNodeInfo(node), test.labels, test.presence}
+		fits, err := labelChecker.CheckNodeLabelPresence(test.pod, test.existingPods, "machine")
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if fits != test.fits {
+			t.Errorf("%s: expected: %v got %v", test.test, test.fits, fits)
+		}
+	}
+}

pkg/scheduler/priorities.go

@@ -18,6 +18,7 @@ package scheduler
 
 import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/golang/glog"
 )
 
@@ -88,3 +89,47 @@ func LeastRequestedPriority(pod api.Pod, podLister PodLister, minionLister Minio
 	}
 	return list, nil
 }
+
+type NodeLabelPrioritizer struct {
+	label    string
+	presence bool
+}
+
+func NewNodeLabelPriority(label string, presence bool) PriorityFunction {
+	labelPrioritizer := &NodeLabelPrioritizer{
+		label:    label,
+		presence: presence,
+	}
+	return labelPrioritizer.CalculateNodeLabelPriority
+}
+
+// CalculateNodeLabelPriority checks whether a particular label exists on a minion or not, regardless of its value
+// Consider the cases where the minions are places in regions/zones/racks and these are identified by labels
+// In some cases, it is required that only minions that are part of ANY of the defined regions/zones/racks be selected
+func (n *NodeLabelPrioritizer) CalculateNodeLabelPriority(pod api.Pod, podLister PodLister, minionLister MinionLister) (HostPriorityList, error) {
+	var score int
+	minions, err := minionLister.List()
+	if err != nil {
+		return nil, err
+	}
+
+	// find the zones that the minions belong to
+	labeledMinions := map[string]bool{}
+	for _, minion := range minions.Items {
+		exists := labels.Set(minion.Labels).Has(n.label)
+		labeledMinions[minion.Name] = (exists && n.presence) || (!exists && !n.presence)
+	}
+
+	result := []HostPriority{}
+	//score int - scale of 0-10
+	// 0 being the lowest priority and 10 being the highest
+	for minionName, success := range labeledMinions {
+		if success {
+			score = 10
+		} else {
+			score = 0
+		}
+		result = append(result, HostPriority{host: minionName, score: score})
+	}
+	return result, nil
+}

pkg/scheduler/priorities_test.go

@@ -18,6 +18,7 @@ package scheduler
 
 import (
 	"reflect"
+	"sort"
 	"testing"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
@@ -238,3 +239,102 @@ func TestLeastRequested(t *testing.T) {
 		}
 	}
 }
+
+func TestNewNodeLabelPriority(t *testing.T) {
+	label1 := map[string]string{"foo": "bar"}
+	label2 := map[string]string{"bar": "foo"}
+	label3 := map[string]string{"bar": "baz"}
+	tests := []struct {
+		pod          api.Pod
+		pods         []api.Pod
+		nodes        []api.Node
+		label        string
+		presence     bool
+		expectedList HostPriorityList
+		test         string
+	}{
+		{
+			nodes: []api.Node{
+				{ObjectMeta: api.ObjectMeta{Name: "machine1", Labels: label1}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine2", Labels: label2}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine3", Labels: label3}},
+			},
+			expectedList: []HostPriority{{"machine1", 0}, {"machine2", 0}, {"machine3", 0}},
+			label:        "baz",
+			presence:     true,
+			test:         "no match found, presence true",
+		},
+		{
+			nodes: []api.Node{
+				{ObjectMeta: api.ObjectMeta{Name: "machine1", Labels: label1}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine2", Labels: label2}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine3", Labels: label3}},
+			},
+			expectedList: []HostPriority{{"machine1", 10}, {"machine2", 10}, {"machine3", 10}},
+			label:        "baz",
+			presence:     false,
+			test:         "no match found, presence false",
+		},
+		{
+			nodes: []api.Node{
+				{ObjectMeta: api.ObjectMeta{Name: "machine1", Labels: label1}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine2", Labels: label2}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine3", Labels: label3}},
+			},
+			expectedList: []HostPriority{{"machine1", 10}, {"machine2", 0}, {"machine3", 0}},
+			label:        "foo",
+			presence:     true,
+			test:         "one match found, presence true",
+		},
+		{
+			nodes: []api.Node{
+				{ObjectMeta: api.ObjectMeta{Name: "machine1", Labels: label1}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine2", Labels: label2}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine3", Labels: label3}},
+			},
+			expectedList: []HostPriority{{"machine1", 0}, {"machine2", 10}, {"machine3", 10}},
+			label:        "foo",
+			presence:     false,
+			test:         "one match found, presence false",
+		},
+		{
+			nodes: []api.Node{
+				{ObjectMeta: api.ObjectMeta{Name: "machine1", Labels: label1}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine2", Labels: label2}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine3", Labels: label3}},
+			},
+			expectedList: []HostPriority{{"machine1", 0}, {"machine2", 10}, {"machine3", 10}},
+			label:        "bar",
+			presence:     true,
+			test:         "two matches found, presence true",
+		},
+		{
+			nodes: []api.Node{
+				{ObjectMeta: api.ObjectMeta{Name: "machine1", Labels: label1}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine2", Labels: label2}},
+				{ObjectMeta: api.ObjectMeta{Name: "machine3", Labels: label3}},
+			},
+			expectedList: []HostPriority{{"machine1", 10}, {"machine2", 0}, {"machine3", 0}},
+			label:        "bar",
+			presence:     false,
+			test:         "two matches found, presence false",
+		},
+	}
+
+	for _, test := range tests {
+		prioritizer := NodeLabelPrioritizer{
+			label:    test.label,
+			presence: test.presence,
+		}
+		list, err := prioritizer.CalculateNodeLabelPriority(test.pod, FakePodLister(test.pods), FakeMinionLister(api.NodeList{Items: test.nodes}))
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		// sort the two lists to avoid failures on account of different ordering
+		sort.Sort(test.expectedList)
+		sort.Sort(list)
+		if !reflect.DeepEqual(test.expectedList, list) {
+			t.Errorf("%s: expected %#v, got %#v", test.test, test.expectedList, list)
+		}
+	}
+}

pkg/scheduler/spreading.go

@@ -80,25 +80,25 @@ func (s *ServiceSpread) CalculateSpreadPriority(pod api.Pod, podLister PodLister
 	return result, nil
 }
 
-type ZoneSpread struct {
+type ServiceAntiAffinity struct {
 	serviceLister ServiceLister
-	zoneLabel     string
+	label         string
 }
 
-func NewZoneSpreadPriority(serviceLister ServiceLister, zoneLabel string) PriorityFunction {
-	zoneSpread := &ZoneSpread{
+func NewServiceAntiAffinityPriority(serviceLister ServiceLister, label string) PriorityFunction {
+	antiAffinity := &ServiceAntiAffinity{
 		serviceLister: serviceLister,
-		zoneLabel:     zoneLabel,
+		label:         label,
 	}
-	return zoneSpread.ZoneSpreadPriority
+	return antiAffinity.CalculateAntiAffinityPriority
 }
 
-func (z *ZoneSpread) ZoneSpreadPriority(pod api.Pod, podLister PodLister, minionLister MinionLister) (HostPriorityList, error) {
+func (s *ServiceAntiAffinity) CalculateAntiAffinityPriority(pod api.Pod, podLister PodLister, minionLister MinionLister) (HostPriorityList, error) {
 	var service api.Service
 	var pods []api.Pod
 	var err error
 
-	service, err = z.serviceLister.GetPodService(pod)
+	service, err = s.serviceLister.GetPodService(pod)
 	if err == nil {
 		selector := labels.SelectorFromSet(service.Spec.Selector)
 		pods, err = podLister.ListPods(selector)
@@ -116,8 +116,8 @@ func (z *ZoneSpread) ZoneSpreadPriority(pod api.Pod, podLister PodLister, minion
 	openMinions := []string{}
 	zonedMinions := map[string]string{}
 	for _, minion := range minions.Items {
-		if labels.Set(minion.Labels).Has(z.zoneLabel) {
-			zone := labels.Set(minion.Labels).Get(z.zoneLabel)
+		if labels.Set(minion.Labels).Has(s.label) {
+			zone := labels.Set(minion.Labels).Get(s.label)
 			zonedMinions[minion.Name] = zone
 		} else {
 			openMinions = append(openMinions, minion.Name)

pkg/scheduler/spreading_test.go

@@ -270,8 +270,8 @@ func TestZoneSpreadPriority(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		zoneSpread := ZoneSpread{serviceLister: FakeServiceLister(test.services), zoneLabel: "zone"}
-		list, err := zoneSpread.ZoneSpreadPriority(test.pod, FakePodLister(test.pods), FakeMinionLister(makeLabeledMinionList(test.nodes)))
+		zoneSpread := ServiceAntiAffinity{serviceLister: FakeServiceLister(test.services), label: "zone"}
+		list, err := zoneSpread.CalculateAntiAffinityPriority(test.pod, FakePodLister(test.pods), FakeMinionLister(makeLabeledMinionList(test.nodes)))
 		if err != nil {
 			t.Errorf("unexpected error: %v", err)
 		}

plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go

@@ -50,7 +50,7 @@ func defaultPriorities() util.StringSet {
 		factory.RegisterPriorityFunction("ServiceSpreadingPriority", algorithm.NewServiceSpreadPriority(factory.ServiceLister), 1),
 		// spreads pods belonging to the same service across minions in different zones
 		// TODO: remove the hardcoding of the "zone" label and move it to a constant
-		factory.RegisterPriorityFunction("ZoneSpreadingPriority", algorithm.NewZoneSpreadPriority(factory.ServiceLister, "zone"), 1),
+		factory.RegisterPriorityFunction("ZoneSpreadingPriority", algorithm.NewServiceAntiAffinityPriority(factory.ServiceLister, "zone"), 1),
 		// EqualPriority is a prioritizer function that gives an equal weight of one to all minions
 		factory.RegisterPriorityFunction("EqualPriority", algorithm.EqualPriority, 0),
 	)

plugin/pkg/scheduler/algorithmprovider/labelchecker/labelchecker.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2014 Google Inc. 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.
+*/
+
+// This is the default algorithm provider for the scheduler.
+package labelchecker
+
+import (
+	algorithm "github.com/GoogleCloudPlatform/kubernetes/pkg/scheduler"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler/factory"
+)
+
+const Provider string = "LabelCheckerProvider"
+
+func init() {
+	factory.RegisterAlgorithmProvider(Provider, defaultPredicates(), defaultPriorities())
+}
+
+func defaultPredicates() util.StringSet {
+	return util.NewStringSet(
+		// Fit is defined based on the presence/absence of a label on a minion, regardless of value.
+		factory.RegisterFitPredicate("NodeLabelPredicate", algorithm.NewNodeLabelPredicate(factory.MinionLister, []string{"region"}, true)),
+	)
+}
+
+func defaultPriorities() util.StringSet {
+	return util.NewStringSet(
+		// Prioritize nodes based on the presence/absence of a label on a minion, regardless of value.
+		factory.RegisterPriorityFunction("NodeLabelPriority", algorithm.NewNodeLabelPriority("", true), 1),
+	)
+}