Commenters here are missing the point — the intent is to build otherwise isolated systems with properties that are very difficult to control, such as varying amounts of clock skew, arbitrary process pauses due to GC cycles or CPU consumption and build a system on top that allows for the storage of mutable state. An example would be a cluster of etcd or dqlite instances (which Kubernetes in multi-master setups also use BTW), or at a larger scale, something like DynamoDB.

It’s one of the more easily approached resources on the design of distributed systems, and a good read.