Update comments

Author: hakman

pkg/model/awsmodel/autoscalinggroup.go

@@ -74,6 +74,9 @@ func (b *AutoscalingGroupModelBuilder) Build(c *fi.CloudupModelBuilderContext) e
 			}
 		}
 
+		// Always create the user data, even for Karpenter manged instance groups
+		// Kaprenter expects the user data to be available in the state store:
+		// ${KOPS_STATE_STORE}/${CLUSTER_NAME}/igconfig/node/${IG_NAME}/nodeupscript.sh
 		userData, err := b.BootstrapScriptBuilder.ResourceNodeUp(c, ig)
 		if err != nil {
 			return err

pkg/model/bootstrapscript.go

@@ -67,7 +67,7 @@ type BootstrapScript struct {
 
 	// nodeupConfig contains the nodeup config.
 	nodeupConfig fi.CloudupTaskDependentResource
-	// nodeupScript contains the nodeup boostrap script.
+	// nodeupScript contains the nodeup bootstrap script, for use with Karpenter.
 	nodeupScript fi.CloudupTaskDependentResource
 }
 

pkg/model/components/nodeterminationhandler.go

@@ -41,6 +41,8 @@ func (b *NodeTerminationHandlerOptionsBuilder) BuildOptions(o *kops.Cluster) err
 	nth := clusterSpec.CloudProvider.AWS.NodeTerminationHandler
 	if nth.Enabled == nil {
 		if clusterSpec.Karpenter != nil && clusterSpec.Karpenter.Enabled {
+			// Karpenter manages its own NTH, so we disable the NTH addon.
+			// https://karpenter.sh/docs/troubleshooting/#aws-node-termination-handler-nth-interactions
 			nth.Enabled = fi.PtrTo(false)
 		} else {
 			nth.Enabled = fi.PtrTo(true)