Fixed a scheduler panic on PodAffinity

pkg/scheduler/algorithm/priorities/interpod_affinity.go

@@ -51,17 +51,16 @@ func NewInterPodAffinityPriority(
 }
 
 type podAffinityPriorityMap struct {
-	// nodes contain all nodes that should be considered
+	// nodes contain all nodes that should be considered.
 	nodes []*v1.Node
-	// counts store the mapping from node name to so-far computed score of
+	// counts store the so-far computed score for each node.
-	// the node.
+	counts []int64
-	counts map[string]*int64
 }
 
 func newPodAffinityPriorityMap(nodes []*v1.Node) *podAffinityPriorityMap {
 	return &podAffinityPriorityMap{
 		nodes:  nodes,
-		counts: make(map[string]*int64, len(nodes)),
+		counts: make([]int64, len(nodes)),
 	}
 }
 
@@ -73,9 +72,9 @@ func (p *podAffinityPriorityMap) processTerm(term *v1.PodAffinityTerm, podDefini
 	}
 	match := priorityutil.PodMatchesTermsNamespaceAndSelector(podToCheck, namespaces, selector)
 	if match {
-		for _, node := range p.nodes {
+		for i, node := range p.nodes {
 			if priorityutil.NodesHaveSameTopologyKey(node, fixedNode, term.TopologyKey) {
-				atomic.AddInt64(p.counts[node.Name], weight)
+				atomic.AddInt64(&p.counts[i], weight)
 			}
 		}
 	}
@@ -102,17 +101,11 @@ func (ipa *InterPodAffinity) CalculateInterPodAffinityPriority(pod *v1.Pod, node
 	hasAffinityConstraints := affinity != nil && affinity.PodAffinity != nil
 	hasAntiAffinityConstraints := affinity != nil && affinity.PodAntiAffinity != nil
 
-	// priorityMap stores the mapping from node name to so-far computed score of
+	// pm stores (1) all nodes that should be considered and (2) the so-far computed score for each node.
-	// the node.
 	pm := newPodAffinityPriorityMap(nodes)
 	allNodeNames := make([]string, 0, len(nodeNameToInfo))
-	lazyInit := hasAffinityConstraints || hasAntiAffinityConstraints
 	for name := range nodeNameToInfo {
 		allNodeNames = append(allNodeNames, name)
-		// if pod has affinity defined, or target node has affinityPods
-		if lazyInit || len(nodeNameToInfo[name].PodsWithAffinity()) != 0 {
-			pm.counts[name] = new(int64)
-		}
 	}
 
 	// convert the topology key based weights to the node name based weights
@@ -216,25 +209,22 @@ func (ipa *InterPodAffinity) CalculateInterPodAffinityPriority(pod *v1.Pod, node
 		return nil, err
 	}
 
-	for _, node := range nodes {
+	for i := range nodes {
-		if pm.counts[node.Name] == nil {
+		if pm.counts[i] > maxCount {
-			continue
+			maxCount = pm.counts[i]
 		}
-		if *pm.counts[node.Name] > maxCount {
+		if pm.counts[i] < minCount {
-			maxCount = *pm.counts[node.Name]
+			minCount = pm.counts[i]
-		}
-		if *pm.counts[node.Name] < minCount {
-			minCount = *pm.counts[node.Name]
 		}
 	}
 
 	// calculate final priority score for each node
 	result := make(schedulerapi.HostPriorityList, 0, len(nodes))
 	maxMinDiff := maxCount - minCount
-	for _, node := range nodes {
+	for i, node := range nodes {
 		fScore := float64(0)
-		if maxMinDiff > 0 && pm.counts[node.Name] != nil {
+		if maxMinDiff > 0 {
-			fScore = float64(schedulerapi.MaxPriority) * (float64(*pm.counts[node.Name]-minCount) / float64(maxCount-minCount))
+			fScore = float64(schedulerapi.MaxPriority) * (float64(pm.counts[i]-minCount) / float64(maxCount-minCount))
 		}
 		result = append(result, schedulerapi.HostPriority{Host: node.Name, Score: int64(fScore)})
 		if klog.V(10) {

pkg/scheduler/algorithm/priorities/interpod_affinity_test.go

@@ -507,6 +507,22 @@ func TestInterPodAffinityPriority(t *testing.T) {
 			expectedList: []schedulerapi.HostPriority{{Host: "machine1", Score: schedulerapi.MaxPriority}, {Host: "machine2", Score: 0}, {Host: "machine3", Score: schedulerapi.MaxPriority}, {Host: "machine4", Score: 0}},
 			name:         "Affinity and Anti Affinity and symmetry: considered only preferredDuringSchedulingIgnoredDuringExecution in both pod affinity & anti affinity & symmetry",
 		},
+		// Cover https://github.com/kubernetes/kubernetes/issues/82796 which panics upon:
+		// 1. Some nodes in a topology don't have pods with affinity, but other nodes in the same topology have.
+		// 2. The incoming pod doesn't have affinity.
+		{
+			pod: &v1.Pod{Spec: v1.PodSpec{NodeName: ""}, ObjectMeta: metav1.ObjectMeta{Labels: podLabelSecurityS1}},
+			pods: []*v1.Pod{
+				{Spec: v1.PodSpec{NodeName: "machine1"}, ObjectMeta: metav1.ObjectMeta{Labels: podLabelSecurityS1}},
+				{Spec: v1.PodSpec{NodeName: "machine2", Affinity: stayWithS1InRegionAwayFromS2InAz}},
+			},
+			nodes: []*v1.Node{
+				{ObjectMeta: metav1.ObjectMeta{Name: "machine1", Labels: labelRgChina}},
+				{ObjectMeta: metav1.ObjectMeta{Name: "machine2", Labels: labelRgChina}},
+			},
+			expectedList: []schedulerapi.HostPriority{{Host: "machine1", Score: schedulerapi.MaxPriority}, {Host: "machine2", Score: schedulerapi.MaxPriority}},
+			name:         "Avoid panic when partial nodes in a topology don't have pods with affinity",
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {