Merge pull request #4022 from kahirokunn/adding-issue-taint

Checking for taint `karpenter.sh/disrupted:NoSchedule` while checking if node is suitable to handle traffic.

pkg/backend/endpoint_utils.go

@@ -13,7 +13,8 @@ const (
 	labelAlphaNodeRoleExcludeBalancer = "alpha.service-controller.kubernetes.io/exclude-balancer"
 	labelEKSComputeType               = "eks.amazonaws.com/compute-type"
 
-	toBeDeletedByCATaint = "ToBeDeletedByClusterAutoscaler"
+	toBeDeletedByCATaint        = "ToBeDeletedByClusterAutoscaler"
+	toBeDeletedByKarpenterTaint = "karpenter.sh/disrupted"
 )
 
 var (
@@ -61,12 +62,17 @@ func GetTrafficProxyNodeSelector(tgb *elbv2api.TargetGroupBinding) (labels.Selec
 // IsNodeSuitableAsTrafficProxy check whether node is suitable as a traffic proxy.
 // This should be checked in additional to the nodeSelector defined in TargetGroupBinding.
 func IsNodeSuitableAsTrafficProxy(node *corev1.Node) bool {
-	// ToBeDeletedByClusterAutoscaler taint is added by cluster autoscaler before removing node from cluster
-	// Marking the node as unsuitable for traffic once the taint is observed on the node
 	for _, taint := range node.Spec.Taints {
+		// ToBeDeletedByClusterAutoscaler taint is added by cluster autoscaler before removing node from cluster
+		// Marking the node as unsuitable for traffic once the taint is observed on the node
 		if taint.Key == toBeDeletedByCATaint {
 			return false
 		}
+		// karpenter.sh/disrupted:NoSchedule taint is added by karpenter before removing node from cluster
+		// Marking the node as unsuitable for traffic once the taint is observed on the node
+		if taint.Key == toBeDeletedByKarpenterTaint && taint.Effect == corev1.TaintEffectNoSchedule {
+			return false
+		}
 	}
 
 	return true

pkg/backend/endpoint_utils_test.go

@@ -131,6 +131,31 @@ func TestIsNodeSuitableAsTrafficProxy(t *testing.T) {
 			},
 			want: false,
 		},
+		{
+			name: "node is ready but tainted with karpenter.sh/disrupted",
+			args: args{
+				node: &corev1.Node{
+					Status: corev1.NodeStatus{
+						Conditions: []corev1.NodeCondition{
+							{
+								Type:   corev1.NodeReady,
+								Status: corev1.ConditionTrue,
+							},
+						},
+					},
+					Spec: corev1.NodeSpec{
+						Unschedulable: false,
+						Taints: []corev1.Taint{
+							{
+								Key:    toBeDeletedByKarpenterTaint,
+								Effect: corev1.TaintEffectNoSchedule,
+							},
+						},
+					},
+				},
+			},
+			want: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {