I believe Raft is supposed to handle this; every modification is a log entry, and every recipient has to ack the log entry, a bit like two-phased commit.
This is incorrect, only reads from the current Raft master are guaranteed to not be stale. In the case of InfluxDB, I think caching is safe because the shard metadata is immutable.
Where are you seeing that cluster metadata is immutable? I don't even know how that would work. Surely nodes, databases, shards, users, permissions, etc. all can change?
