Migrating from one Kubernetes cluster to another

[virtxx]

I need to migrate a running app from one Kubernetes (OpenShift) cluster with several pods in several nodes, to another new cluster not currently serving traffic. The kubernetes nodes of the two clusters are on the same network but the two Kubernetes/OpenShift clusters are otherwise distinct. I need to make the pods on the new cluster join the Hazelcast cluster. What would be a good way to go about doing this? The running app is using the Kubernetes plug-in to find peers. I can upgrade the app code or configuration in the running app if needed in preparation for the upgrade, but it has to be without down time.

I've been considering taking a list of peers on the old cluster and typing into the config on the new (in addition to the kubernetes plugin discovery which will of course only find the peers on the new cluster) but I'm unsure if it will work given it is two different kubernetes installations and hence have distinct kubeproxy rules etc.