fix incorrect pod equivalency check for pod specs with volume

cluster-autoscaler/core/equivalence_groups.go

@@ -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) && podSpecSemanticallyEqual(pod.Spec, g.representant.Spec) {
 				matchingFound = true
 				podEquivalenceGroups[g.id] = append(podEquivalenceGroups[g.id], pod)
 				break
@@ -87,3 +87,22 @@ func groupPodsBySchedulingProperties(pods []*apiv1.Pod) map[equivalenceGroupId][
 
 	return podEquivalenceGroups
 }
+
+func podSpecSemanticallyEqual(p1 apiv1.PodSpec, p2 apiv1.PodSpec) bool {
+	p1Spec := sanitizeVolumesAndMounts(p1)
+	p2Spec := sanitizeVolumesAndMounts(p2)
+	return apiequality.Semantic.DeepEqual(p1Spec, p2Spec)
+}
+
+// sanitizeVolumesAndMounts removes volumes and volume mounts from the pod spec
+// Due to the generated suffixes, a strict DeepEquals check will fail and generate
+// an equivalence group per pod which is undesirable.
+// This is also applicable to a pod without volumes scenario due to the volume
+// projection of the default service account onto the kube-api-access volume
+func sanitizeVolumesAndMounts(podSpec apiv1.PodSpec) apiv1.PodSpec {
+	podSpec.Volumes = nil
+	for i := range podSpec.Containers {
+		podSpec.Containers[i].VolumeMounts = nil
+	}
+	return podSpec
+}

cluster-autoscaler/core/equivalence_groups_test.go

@@ -47,6 +47,15 @@ func TestGroupSchedulablePodsForNode(t *testing.T) {
 		},
 	}
 
+	rc3 := apiv1.ReplicationController{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "rc3",
+			Namespace: "default",
+			SelfLink:  "api/v1/namespaces/default/replicationcontrollers/rc2",
+			UID:       "12345678-1234-1234-1234-12345678901a",
+		},
+	}
+
 	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 +65,16 @@ 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"}}
+	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"}}
+	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 +83,7 @@ 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 {
@@ -102,3 +118,31 @@ func TestGroupSchedulablePodsForNode(t *testing.T) {
 		assert.True(t, w.found, fmt.Errorf("Expected pod group: %+v", w))
 	}
 }
+
+func TestPodSpecSemanticallyEqual(t *testing.T) {
+	rc1 := apiv1.ReplicationController{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "rc1",
+			Namespace: "default",
+			UID:       "12345678-1234-1234-1234-123456789012",
+		},
+	}
+	p1_1 := BuildTestPod("p1_1", 1500, 200000)
+	p1_1.Spec.Volumes = []apiv1.Volume{{Name: "vol-8bx7p"}}
+	p1_1.OwnerReferences = GenerateOwnerReferences(rc1.Name, "ReplicationController", "extensions/v1beta1", rc1.UID)
+	p1_2 := BuildTestPod("p1_2", 1500, 200000)
+	p1_2.Spec.Containers[0].VolumeMounts = []apiv1.VolumeMount{{Name: "vol-3en7l"}}
+	p1_2.OwnerReferences = GenerateOwnerReferences(rc1.Name, "ReplicationController", "extensions/v1beta1", rc1.UID)
+	assert.True(t, podSpecSemanticallyEqual(p1_1.Spec, p1_2.Spec))
+}
+
+func TestSanitizeVolumesAndMounts(t *testing.T) {
+	p1 := BuildTestPod("p1", 1500, 200000)
+	p1.Spec.Volumes = []apiv1.Volume{{Name: "vol1"}, {Name: "vol2"}}
+	p2 := BuildTestPod("p2", 1500, 200000)
+	p2.Spec.Containers[0].VolumeMounts = []apiv1.VolumeMount{{Name: "volmount1"}}
+	p1SanitizedSpec := sanitizeVolumesAndMounts(p1.Spec)
+	p2SanitizedSpec := sanitizeVolumesAndMounts(p2.Spec)
+	assert.Nil(t, p1SanitizedSpec.Volumes)
+	assert.Nil(t, p2SanitizedSpec.Containers[0].VolumeMounts)
+}