VPC CNI Limited IP Addresses Alert

[sablumiah]

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

https://github.com/ministryofjustice/cloud-platform-terraform-eks-add-ons/blob/main/main.tf#L71

kubectl set env daemonset aws-node -n kube-system ENABLE_PREFIX_DELEGATION=true

Issue: Not enough IP addresses available per node due to the above being set to false (False is the default value when vpc cni is upgraded)

We need to devise a test or a check to be alerted if this issue happens again.

Things to look at:

Using VPC CNI metrics OS alert based on logs