Merge pull request #857 from openshift-cherrypick-robot/cherry-pick-8…

…10-to-release-4.12

[release-4.12] OCPBUGS-3517: Ingress controller should not have affinity policy in single-replica clusters

pkg/operator/controller/ingress/deployment.go

@@ -282,6 +282,17 @@ func desiredRouterDeployment(ci *operatorv1.IngressController, ingressController
 		// node.  Thus no affinity policy is required when using
 		// HostNetwork.
 	case operatorv1.PrivateStrategyType, operatorv1.LoadBalancerServiceStrategyType, operatorv1.NodePortServiceStrategyType:
+		// Non-HA ingress controllers should have default deployment
+		// strategy with no affinity policy. We need to check the cluster
+		// topology in order to determine whether the affinity rule is
+		// required. Just checking desiredReplicas would be incorrect
+		// because we need the rule on multi-node clusters, even if
+		// desiredReplicas is 1, so that a rolling update schedules
+		// the new pod to the same node as the old pod.
+		if singleReplica(ingressConfig, infraConfig) {
+			break
+		}
+
 		// To avoid downtime during a rolling update, we need two
 		// things: a deployment strategy and an affinity policy.  First,
 		// the deployment strategy: During a rolling update, we want the
@@ -1690,3 +1701,14 @@ func capReloadIntervalValue(interval time.Duration) time.Duration {
 		return interval
 	}
 }
+
+// SingleReplica determines if ingress controllers are deployed in SingleReplica topology
+func singleReplica(ingressConfig *configv1.Ingress, infraConfig *configv1.Infrastructure) bool {
+	// DefaultPlacement affects which topology field we're interested in
+	topology := infraConfig.Status.InfrastructureTopology
+	if ingressConfig.Status.DefaultPlacement == configv1.DefaultPlacementControlPlane {
+		topology = infraConfig.Status.ControlPlaneTopology
+	}
+
+	return topology == configv1.SingleReplicaTopologyMode
+}

pkg/operator/controller/ingress/deployment_test.go

@@ -804,6 +804,37 @@ func TestDesiredRouterDeploymentHostNetworkNil(t *testing.T) {
 	checkContainerPort(t, deployment, "metrics", 1936)
 }
 
+func TestDesiredRouterDeploymentSingleReplica(t *testing.T) {
+	ic, ingressConfig, _, apiConfig, networkConfig, _ := getRouterDeploymentComponents(t)
+
+	infraConfig := &configv1.Infrastructure{
+		Status: configv1.InfrastructureStatus{
+			PlatformStatus: &configv1.PlatformStatus{
+				Type: configv1.IBMCloudPlatformType,
+			},
+			ControlPlaneTopology:   configv1.ExternalTopologyMode,
+			InfrastructureTopology: configv1.SingleReplicaTopologyMode,
+		},
+	}
+
+	deployment, err := desiredRouterDeployment(ic, ingressControllerImage, ingressConfig, infraConfig, apiConfig, networkConfig, false, false, nil)
+	if err != nil {
+		t.Fatalf("invalid router Deployment: %v", err)
+	}
+
+	if *deployment.Spec.Replicas != 1 {
+		t.Errorf("expected replicas to be 1, got %d", *deployment.Spec.Replicas)
+	}
+
+	if deployment.Spec.Template.Spec.Affinity != nil {
+		t.Errorf("expected no affinity, got %+v", *deployment.Spec.Template.Spec.Affinity)
+	}
+
+	if deployment.Spec.Strategy.Type != "" || deployment.Spec.Strategy.RollingUpdate != nil {
+		t.Errorf("expected default deployment strategy, got %s", deployment.Spec.Strategy.Type)
+	}
+}
+
 func checkContainerPort(t *testing.T, d *appsv1.Deployment, portName string, port int32) {
 	t.Helper()
 	for _, p := range d.Spec.Template.Spec.Containers[0].Ports {