Merge pull request #1149 from cdirubbio/patch-13

Additional Information on CoreDNS in EKS Auto Mode

Author: pgasca

latest/ug/automode/auto-networking.adoc

@@ -86,3 +86,10 @@ For more information, see <<auto-configure-alb>> or <<auto-configure-nlb>>.
 * {aws} does not support migrating load balancers from the self managed {aws} load balancer controller to management by EKS Auto Mode.
 * The `networking.ingress.ipBlock` field in `TargetGroupBinding` spec is not supported. 
 * If your worker nodes use custom security groups (not `eks-cluster-sg-*` naming pattern), your cluster role needs additional IAM permissions.  The default EKS-managed policy only allows EKS to modify security groups named `eks-cluster-sg-*`. Without permission to modify your custom security groups, EKS cannot add the required ingress rules that allow ALB/NLB traffic to reach your pods.
+
+[#dns-consider]
+==== CoreDNS considerations
+
+EKS Auto Mode does not use the traditional CoreDNS deployment to provide DNS resolution within the cluster. Instead, Auto Mode nodes utilize CoreDNS running as a system service directly on each node. If transitioning a traditional cluster to Auto Mode, you can remove the CoreDNS deployment from your cluster once your workloads have been moved to the Auto Mode nodes.
+
+IMPORTANT: If you plan to maintain a cluster with both Auto Mode and non-Auto Mode nodes, you must retain the CoreDNS deployment. Non-Auto Mode nodes rely on the traditional CoreDNS pods for DNS resolution, as they cannot access the node-level DNS service that Auto Mode provides.