The Google Container Engine's (GKE) documentation says: "There’s no vendor lock-in, you’re free to take your workloads out of Container Engine and run them anywhere Kubernetes is supported, including on your own on-premise servers."
Still, GKE is a managed environment for Kubernetes and I was wondering how difficult it would be to take your workloads out of GKE after, say, 2-3 years and run them on your own premises. What do you need to pay attention to maintain maximum portability?