Upgrade Karpenter node group to 1.27 fails

Hello,

I have upgraded my EKS cluster from 1.26 to 1.27. The managed EC2 node group for Karpenter, which consists of two on demand t3.small amd64 instances, should be upgraded to 1.27 as well. This fails after half an hour with the message "Couldn't proceed with upgrade process as new nodes are not joining node group karpenter".

I have tried a rolling update as well as a forced update. I have also tried setting the maximum allowed number of nodes to 4 before performing the node group upgrade. No extra nodes are provisioned and the failure is the same.

In the past, the upgrade from 1.25 to 1.26 went fine.

Best regards,

Werner.