> What happens if I'm monitoring and see an elevated clock-skew?
If you have monitoring that can detect that, NTP should also be able to run and correct it, apart from some very weird failure modes of the network itself (like traffic dropping in one direction).
> I think CockroachDB will be amazing when cloud providers start offering APIs for High-Resolution Clocks as a service
With the hybrid logical clocks that cockroach uses (basically wall time + vector clock), they don’t need to be all that precise. The trade off it makes is giving up linearizability (aka external serializability).
Spanner gets that by making every transaction wait for the maximum clock skew (7ms, with their atomic and GPS clock systems). But in order to run on commodity hardware Cockroach forewent it, in favor of allowing more acceptable skew.