AWS EKS does not support t3a and r5ad instance types yet

AWS released t3a instance family. I tried to use t3a series on new EKS cluster. But I got the following error.

$ kubectl describe pod utils
Type Reason Age From Message
---- ------ ---- ---- -------
  Warning  FailedCreatePodSandBox  24m                    kubelet,  Failed create pod sandbox: rpc error: code = Unknown desc = failed to set up sandbox container "7ec0142b4f93598e414998215c3b5227a07426db96c8a6e34db347bb97bb65a5" network for pod "utils": NetworkPlugin cni failed to set up pod "utils_default" network: add cmd: failed to assign an IP address to container
Warning FailedCreatePodSandBox 24m

when I checked worker logs I got the following error.

May 21 20:59:11 ip-10–65–8–15 cloud-init: No entry for t3a.medium in /etc/eks/eni-max-pods.txt. Not setting max pods for kubelet

It means, AWS VPC CNI shipped with eks 1.2.7 AMI does not support t3a series.

There is a PR for it at

Until AWS upgrade AMI CNI version to 1.5, do not use t3a, i3en and r5ad instance families.


Devops Engineer at Feedstock Inc.