I have done one massive AWS + kops > GKE migration and several smaller migrations between AWS/GCP/Azure. My experience leads me to believe the main problems st

I have done one massive AWS + kops > GKE migration and several smaller migrations between AWS/GCP/Azure. My experience leads me to believe the main problems stem from adopting IaaS/PaaS specific stuff outside of k8s. If you aren't doing that they are very portable and even if you are if you are using standard stuff like managed PostgreSQL/MySQL then it's still easy. Where that breaks down is very vendor specific stuff, ala Spanner, queues/logs like SQS/PubSub etc. If you are using those and your architecture is tied to specific semantics of them you are in for a rough time. I personally try to avoid any and all of those. Not for vendor lock-in reasons but because I greatly dislike not being able to run everything locally in exactly the same configuration it will be deployed in. So I run PostgreSQL in k8s using Patroni, Kafka or Pulsar for queue/log, etc and that is about it usually. I generally don't need/use other things. Maybe memcached if there is a good need for it over say Caffiene (in-memory cache). This is awesome because it means it's super super easy to have staging/UAT environment or even preview environments on PRs and I can run integration tests against the whole stack E2E without spinning up/manipulating cloud provider resources.