OpenReplica from my research group is a highly available FOSS coordination service for data centers. It can be used for implementing locking, fail over, leader election, group membership and other coordination services. It differs from ZooKeeper in two critical ways:
It uses an object-oriented API. This makes it much easier to write coordination services. Synchronization code for OpenReplica looks exactly like its textbook counterpart; there is no need to master a file and upcall-based API like in ZooKeeper and Chubby.
It enables dynamic membership updates to the replica set. There is no need for static configuration files. The system is integrated into DNS (authoritative, slave for OpenReplica, or Amazon Route 53).
We actively support the system, do not hesitate to let us know if you have further questions.
