Interesting. Maybe hashicorp should release an etcd compatible layer for Consul. Or CockroachDB even. Both have one thing etcd does not...inbuilt WAN support.
etcd can cross WAN links with tuning for the expected latencies. Tuning latencies is required to ensure the leader election algorithms know when to trigger a failure[1].
Yes, you can sort of detune the whole cluster. That's not quite the same as Consul's and CockroachDB's specific WAN awareness. Those two take different approaches, but do specifically understand and compensate.
>What is your use case?
Contract work, so use case varies. I agree that etcd is often the right answer.
Right, etcd's entire focus is on being a consensus database for distributed systems needing coordination, locking, etc. So, eventually consistent WAN replication hasn't really been a focus.
I do think this sort of cross-cluster key replication is useful and we offer it as a userspace external tool called make-mirror[1].
Worth noting that CockroachDB isn't using an eventually consistent model. Yes, it's not the same thing as etcd, but I can see some potential use case overlap.
What is your use case?
[1] https://coreos.com/etcd/docs/latest/tuning.html