EKS on Outposts Server

To provision an EC2 instance in an AWS Outpost to be associated with an extended EKS cluster in the region:

• Launch the EC2 instance into the private subnet that you created in the Outpost. Make sure to select the subnet and security group created specifically for the Outpost.
• When launching, specify the placement group if you want multiple instances to be closely located on the Outpost hardware for low latency.
• The instance must be able to communicate securely with the EKS cluster API endpoint, typically over HTTPS on port 443. Ensure the security group and network access control lists allow this inbound traffic.
• Use the AWS CLI or SDK to associate the EC2 instance IP with the EKS cluster as a node. For example:

eksctl create nodegroup \
--cluster eks-cluster \
--nodegroup-name outpost-nodes \
--node-type c5.large \
--nodes-min 1 \
--nodes-max 3 \
--nodes-max 3 \
--region us-east-1 \
--ssh-access \
--ssh-public-key path/to/key.pub

https://aws.amazon.com/blogs/containers/deploy-an-amazon-eks-cluster-across-aws-outposts-with-intra-vpc-communication/

EKS on Outposts Server is not supported by AWS. It just works in Outposts Racks both Extended or Local EKS clusters.