fix incorrect pod equivalency check for pod specs with volume

cluster-autoscaler/core/equivalence_groups.go

@@ -17,10 +17,10 @@ limitations under the License.
 package core
 
 import (
+	"k8s.io/autoscaler/cluster-autoscaler/core/utils"
 	"reflect"
 
 	apiv1 "k8s.io/api/core/v1"
-	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/autoscaler/cluster-autoscaler/processors/status"
 	"k8s.io/autoscaler/cluster-autoscaler/utils/drain"
@@ -67,7 +67,7 @@ func groupPodsBySchedulingProperties(pods []*apiv1.Pod) map[equivalenceGroupId][
 
 		matchingFound := false
 		for _, g := range equivalenceGroupsByController[controllerRef.UID] {
-			if reflect.DeepEqual(pod.Labels, g.representant.Labels) && apiequality.Semantic.DeepEqual(pod.Spec, g.representant.Spec) {
+			if reflect.DeepEqual(pod.Labels, g.representant.Labels) && utils.PodSpecSemanticallyEqual(pod.Spec, g.representant.Spec) {
 				matchingFound = true
 				podEquivalenceGroups[g.id] = append(podEquivalenceGroups[g.id], pod)
 				break

cluster-autoscaler/core/equivalence_groups_test.go

@@ -47,6 +47,16 @@ func TestGroupSchedulablePodsForNode(t *testing.T) {
 		},
 	}
 
+	rc3 := apiv1.ReplicationController{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "rc3",
+			Namespace: "default",
+			SelfLink:  "api/v1/namespaces/default/replicationcontrollers/rc3",
+			UID:       "12345678-1234-1234-1234-12345678901e",
+		},
+	}
+
+	projectedSAVol := BuildServiceTokenProjectedVolumeSource("path")
 	p1 := BuildTestPod("p1", 1500, 200000)
 	p2_1 := BuildTestPod("p2_1", 3000, 200000)
 	p2_1.OwnerReferences = GenerateOwnerReferences(rc1.Name, "ReplicationController", "extensions/v1beta1", rc1.UID)
@@ -56,10 +66,16 @@ func TestGroupSchedulablePodsForNode(t *testing.T) {
 	p3_1.OwnerReferences = GenerateOwnerReferences(rc2.Name, "ReplicationController", "extensions/v1beta1", rc2.UID)
 	p3_2 := BuildTestPod("p3_2", 100, 200000)
 	p3_2.OwnerReferences = GenerateOwnerReferences(rc2.Name, "ReplicationController", "extensions/v1beta1", rc2.UID)
-	unschedulablePods := []*apiv1.Pod{p1, p2_1, p2_2, p3_1, p3_2}
+	p4_1 := BuildTestPod("p4_1", 100, 200000)
+	p4_1.OwnerReferences = GenerateOwnerReferences(rc2.Name, "ReplicationController", "extensions/v1beta1", rc3.UID)
+	p4_1.Spec.Volumes = []apiv1.Volume{{Name: "kube-api-access-nz94b", VolumeSource: apiv1.VolumeSource{Projected: projectedSAVol}}}
+	p4_2 := BuildTestPod("p4_2", 100, 200000)
+	p4_2.OwnerReferences = GenerateOwnerReferences(rc2.Name, "ReplicationController", "extensions/v1beta1", rc3.UID)
+	p4_2.Spec.Volumes = []apiv1.Volume{{Name: "kube-api-access-mo25i", VolumeSource: apiv1.VolumeSource{Projected: projectedSAVol}}}
+	unschedulablePods := []*apiv1.Pod{p1, p2_1, p2_2, p3_1, p3_2, p4_1, p4_2}
 
 	podGroups := groupPodsBySchedulingProperties(unschedulablePods)
-	assert.Equal(t, 3, len(podGroups))
+	assert.Equal(t, 4, len(podGroups))
 
 	wantedGroups := []struct {
 		pods  []*apiv1.Pod
@@ -68,6 +84,7 @@ func TestGroupSchedulablePodsForNode(t *testing.T) {
 		{pods: []*apiv1.Pod{p1}},
 		{pods: []*apiv1.Pod{p2_1, p2_2}},
 		{pods: []*apiv1.Pod{p3_1, p3_2}},
+		{pods: []*apiv1.Pod{p4_1, p4_2}},
 	}
 
 	equal := func(a, b []*apiv1.Pod) bool {

cluster-autoscaler/utils/test/test_utils.go

@@ -65,6 +65,20 @@ func BuildTestPod(name string, cpu int64, mem int64) *apiv1.Pod {
 	return pod
 }
 
+// BuildServiceTokenProjectedVolumeSource returns a ProjectedVolumeSource with SA token
+// projection
+func BuildServiceTokenProjectedVolumeSource(path string) *apiv1.ProjectedVolumeSource {
+	return &apiv1.ProjectedVolumeSource{
+		Sources: []apiv1.VolumeProjection{
+			{
+				ServiceAccountToken: &apiv1.ServiceAccountTokenProjection{
+					Path: path,
+				},
+			},
+		},
+	}
+}
+
 const (
 	// cannot use constants from gpu module due to cyclic package import
 	resourceNvidiaGPU = "nvidia.com/gpu"

cluster-autoscaler/utils/utils.go

@@ -18,6 +18,7 @@ package utils
 
 import (
 	apiv1 "k8s.io/api/core/v1"
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	klog "k8s.io/klog/v2"
 
 	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider"
@@ -54,3 +55,38 @@ func FilterOutNodes(nodes []*apiv1.Node, nodesToFilterOut []*apiv1.Node) []*apiv
 
 	return filtered
 }
+
+// PodSpecSemanticallyEqual returns if two pod specs are similar after dropping
+// the fields we don't care about
+func PodSpecSemanticallyEqual(p1 apiv1.PodSpec, p2 apiv1.PodSpec) bool {
+	p1Spec := sanitizedProjectedVolumesAndMounts(p1)
+	p2Spec := sanitizedProjectedVolumesAndMounts(p2)
+	return apiequality.Semantic.DeepEqual(p1Spec, p2Spec)
+}
+
+// sanitizedProjectedVolumesAndMounts returns a pod spec with projected volumes
+// and their mounts removed
+// Due to the generated suffixes, a strict DeepEquals check will fail and generate
+// an equivalence group per pod which is undesirable.
+// Projected volumes do not impact scheduling so we should ignore them
+func sanitizedProjectedVolumesAndMounts(podSpec apiv1.PodSpec) apiv1.PodSpec {
+	var projectedVolumeNames []string
+	for i, v := range podSpec.Volumes {
+		if v.Projected != nil {
+			projectedVolumeNames = append(projectedVolumeNames, v.Name)
+			podSpec.Volumes[i] = apiv1.Volume{}
+		}
+	}
+
+	for _, pv := range projectedVolumeNames {
+		for c := range podSpec.Containers {
+			for v, mount := range podSpec.Containers[c].VolumeMounts {
+				if mount.Name == pv {
+					podSpec.Containers[c].VolumeMounts[v] = apiv1.VolumeMount{}
+				}
+			}
+		}
+	}
+
+	return podSpec
+}