I have an 3 node IKE2 cluster setup for rancher server with a Load Balancer in front. I need to change the IP addresses of the 3 nodes, but finding that kubectl no longer works. Is it possible to change IP addresses once RKE2 has been installed?

Not easily. You basically have to pick one of the servers, do a --cluster-reset on it to set it back to single-node cluster with the current IP, then delete the DB files off the other servers and rejoin them. IP address are expected not to change for the life of the node.

That's helpful. Thanks.