Redis Cluster data migration in two differnt Kubernetes Clusters

There are two possible approaches to establish connection between clusters:

NodePort - Exposes the service on each Node’s IP at a static port (the NodePort). A ClusterIP service, to which the NodePort service routes, is automatically created. You’ll be able to contact the NodePort service, from outside the cluster, by requesting <NodeIP>:<NodePort>
LoadBalancer - Exposes the Service externally using a cloud provider’s load balancer. NodePort and ClusterIP services, to which the external load balancer routes, are automatically created.
ingress (both 1st and 3rd party implementations) - more flexible then previous two, but only works with HTTP/HTTPS.

Istio supports multi-cluster deployment model. However, if you don't have service mesh deployed, doing so may be too much for single task use.

Once you have connection established between clusters you can migrate Redis using MIGRATE command, or redis-migrate-tool proposed in comments.

CodeHunter