test of even distribution of replicas for removing cluster scenario

Signed-off-by: chaosi-zju <[email protected]>

Author: chaosi-zju

pkg/scheduler/core/generic_scheduler_test.go

@@ -431,6 +431,74 @@ func Test_EvenDistributionOfReplicas(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		// Test Case No.7 of even distribution of replicas: ensure as much inertia as possible in removing cluster scenarios
+		// 1. create deployment (replicas=6), weight=1:1:1:1
+		// 2. check four member cluster replicas, can be 2:2:1:1、2:1:2:1、2:1:1:2、1:2:2:1、1:2:1:2、1:1:2:2
+		// 3. delete the member4 cluster in case of only one replica has been allocated to the member4 cluster
+		// 4. check three left member cluster replicas, the original replica in member4 cluster will be scaled to another cluster with one replica, just like:
+		//    * 2:2:1:1 --> 2:2:2
+		//    * 2:1:2:1 --> 2:2:2
+		//    * 1:2:2:1 --> 2:2:2
+		{
+			name: "replica 6, static weighted 1:1:1:1, remove a cluster and change static weight to 1:1:1, before change",
+			clusters: []*clusterv1alpha1.Cluster{
+				helper.NewCluster(ClusterMember1),
+				helper.NewCluster(ClusterMember2),
+				helper.NewCluster(ClusterMember3),
+				helper.NewCluster(ClusterMember4),
+			},
+			object: workv1alpha2.ResourceBindingSpec{
+				Replicas: 6,
+			},
+			placement: &policyv1alpha1.Placement{
+				ReplicaScheduling: &policyv1alpha1.ReplicaSchedulingStrategy{
+					ReplicaSchedulingType:     policyv1alpha1.ReplicaSchedulingTypeDivided,
+					ReplicaDivisionPreference: policyv1alpha1.ReplicaDivisionPreferenceWeighted,
+					WeightPreference: &policyv1alpha1.ClusterPreferences{
+						StaticWeightList: []policyv1alpha1.StaticClusterWeight{
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember1}}, Weight: 1},
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember2}}, Weight: 1},
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember3}}, Weight: 1},
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember4}}, Weight: 1},
+						},
+					},
+				},
+			},
+			previousResultToNewResult: map[string][]string{
+				"": {"2:2:1:1", "2:1:2:1", "2:1:1:2", "1:2:2:1", "1:2:1:2", "1:1:2:2"},
+			},
+			wantErr: false,
+		},
+		{
+			name: "replica 6, static weighted 1:1:1:1, remove a cluster and change static weight to 1:1:1, after change",
+			clusters: []*clusterv1alpha1.Cluster{
+				helper.NewCluster(ClusterMember1),
+				helper.NewCluster(ClusterMember2),
+				helper.NewCluster(ClusterMember3),
+			},
+			object: workv1alpha2.ResourceBindingSpec{
+				Replicas: 6,
+			},
+			placement: &policyv1alpha1.Placement{
+				ReplicaScheduling: &policyv1alpha1.ReplicaSchedulingStrategy{
+					ReplicaSchedulingType:     policyv1alpha1.ReplicaSchedulingTypeDivided,
+					ReplicaDivisionPreference: policyv1alpha1.ReplicaDivisionPreferenceWeighted,
+					WeightPreference: &policyv1alpha1.ClusterPreferences{
+						StaticWeightList: []policyv1alpha1.StaticClusterWeight{
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember1}}, Weight: 1},
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember2}}, Weight: 1},
+							{TargetCluster: policyv1alpha1.ClusterAffinity{ClusterNames: []string{ClusterMember3}}, Weight: 1},
+						},
+					},
+				},
+			},
+			previousResultToNewResult: map[string][]string{
+				"2:2:1:1": {"2:2:2"},
+				"2:1:2:1": {"2:2:2"},
+				"1:2:2:1": {"2:2:2"},
+			},
+			wantErr: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {