We're currently running a Kubernetes 1.0 cluster on AWS in production, and we'd like to spin up a second cluster to test out 1.1. Based on the AWS helper functions, it looks like multiple clusters aren't supported, but I wanted to be sure. There's a doc that describes running multiple clusters, but it's fairly brief.
In general, we'd like to have a second cluster continuously running for testing purposes. It seems like this would be a fairly common need.
You should be able to run a second cluster by setting INSTANCE_PREFIX before running kube-up. That variable in turn sets CLUSTER_ID which should parameterize everything in the cluster/aws/* scripts.