ClickHouse Keeper is a ZooKeeper alternative.

Network protocol

The network protocol used by clients to talk to ClickHouse Keeper is compatible with the ZooKeeper protocol. This means you can use any ZooKeeper client to talk to ClickHouse Keeper, and the ClickHouse keeper-client to talk to ZooKeeper servers.

The protocol used by ClickHouse Keeper nodes to talk to each other is not compatible with ZooKeeper. This means you cannot run mixed clusters with some nodes running ZooKeeper and others using ClickHouse Keeper.