Allow running on control plane nodes, but prefer worker nodes

helm/cluster-aws/templates/aws-nth-helmrelease.yaml

@@ -1,6 +1,31 @@
 {{/* Default Helm values for the app */}}
 {{/* See schema for the appropriate app version here https://github.com/giantswarm/aws-nth-bundle/blob/main/helm/aws-nth-bundle/values.schema.json */}}
 {{- define "defaultAwsNodeTerminationHandlerHelmValues" }}
+awsNodeTerminationHandler:
+  values:
+    image:
+      registry: {{ include "awsContainerImageRegistry" $ }}
+
+    # Allow running on control plane nodes. On deletion, CAPI will first delete the worker nodes
+    # and we still want aws-node-termination-handler to take care of the last workers' EC2 lifecycle
+    # hooks since they otherwise won't be completed, resulting in unnecessary waiting time before
+    # AWS can terminate the instances
+    # (see `AWSMachinePool.spec.lifecycleHooks["aws-node-termination-handler"].heartbeatTimeout`).
+    # This runs on workers by default but allows moving pods to control plane nodes. Requires
+    # queue processing mode i.e. running as `Deployment`, not `DaemonSet`.
+    affinity:
+      nodeAffinity:
+        preferredDuringSchedulingIgnoredDuringExecution:
+          - preference:
+              matchExpressions:
+                - key: node-role.kubernetes.io/control-plane
+                  operator: DoesNotExist
+            weight: 10
+    tolerations:
+      - effect: NoSchedule
+        operator: Exists
+        key: node-role.kubernetes.io/control-plane
+
 clusterID: {{ include "resource.default.name" $ }}
 {{- if (.Values.global.connectivity.proxy).enabled }}
 proxy: