We're thinking about using Zookeeper as our coordination service and also for doing group membership in the Amazon Cloud. Currently our applications are deployed in Amazon Cloud on multiple availability zones (i.e. data centers), so this means that ZK nodes will be talking across datacenters. I'm assuming that the additional latency from going across datacenters shouldn't be too big of an issue. Also, we are paranoid about security in the cloud, so we'd like to use https as the communications protocol for Zookeeper -- not sure if this is a trivial thing to do or not. Wondering if anyone's already doing this today or whether Zookeeper is not the right solution given our environment currently.