In which case, you could equally use v1 or v5 UUIDs. Plus a UUID can be generated by a source outside your network -- eg, client side, with the ability to trea

In which case, you could equally use v1 or v5 UUIDs. Plus a UUID can be generated by a source outside your network -- eg, client side, with the ability to treat them as quasi-nonces for replay detection. Or inside your network, during long-running partitions. The bigger question is: why would I install, manage, update, monitor zookeeper/etcd and write my own custom ID generator and all the storage mechanisms around it, when I can just use UUIDs?