Context

EKS clusters have a default limitation on the number of pods that can be run per node. Although there is an option to increase this limit through VPC-CNI prefix delegation, this feature is not activated on our platform.

Answer

Currently, we do not support enabling VPC-CNI prefix delegation to increase the number of pods per node beyond the default limit. This decision is based on several important technical constraints:

• Activation would require major modifications to the existing network architecture, including:

  • Reallocation of CIDRs for each ENI per node

  • Reconfiguration of security groups and network policies

  • Updating the aws-node DaemonSet

• Technical restrictions:

  • This feature is only compatible with AWS Nitro nodes

  • Windows nodes are not supported

• For existing clusters, migration to a new subnet would be necessary to avoid network conflicts

If you need to host a large number of pods, we recommend adjusting your architecture by using additional nodes rather than increasing the number of pods per node.

For more information about this feature, you can consult the AWS documentation:

• https://docs.aws.amazon.com/eks/latest/userguide/cni-increase-ip-addresses.html

• https://docs.aws.amazon.com/eks/latest/userguide/cni-increase-ip-addresses-procedure.html

• https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-prefix-eni.html