For basic SETNX single instance redis instances, sure. But for the Redlock algorithm, I've never encountered anyone that was already running 5 redis masters to

For basic SETNX single instance redis instances, sure. But for the Redlock algorithm, I've never encountered anyone that was already running 5 redis masters to use out of convenience. You're much more likely to have an etcd, consul, Zookeeper, etc cluster that you could use for coarse-grained distributed locking.