Yes - the ASG will replace individual nodes one at a time. The issue tracked in
https://github.com/pulumi/pulumi-eks/issues/40 is that this process does not interact cleanly with Kuberenetes node drainging, so when a node is replaced, the pods on that node will die suddenly, instead of being migrated off prior to shutdown.
This is something that EKS itself has no support for yet unfortunately. We believe we can help solve this problem in
@pulumi/eks
(we've done similar things for ECS) - and plan to do that as part of
https://github.com/pulumi/pulumi-eks/issues/40.