Author here. The plan is to get spinnaker setup on the cluster. It's a collection of around 8 microservices. Kubernetes should handle HA just fine. 20 cores and 10GB of memory for the cluster. I can build another one of these and put it in a separate room for multi-region ;)
Don't think that is enough, check if your next door neighbor is willing to plug one of these in their coat closet - that gives you multi zone. Then ship one to me (or I can build one myself) and host it in San Francisco, that gives us multi region. Are you game?