The nodes in a ZooKeeper tree are called znodes. Version numbers for data modifications, ACL changes, and timestamps are kept by Znodes in a structure. ZooKeeper uses the version number and timestamp to verify the cache and guarantee that updates are coordinated. Each time the data on Znode changes, the version number connected with it grows.

There are three different types of Znodes:

Persistence Znode: These are znodes that continue to function even after the client who created them has been disconnected. Unless otherwise specified, all znodes are persistent by default.

Ephemeral Znode: Ephemeral znodes are only active while the client is still alive. When the client who produced them disconnects from the ZooKeeper ensemble, the ephemeral Znodes are automatically removed. They have a significant part in the election of the leader.

Sequential Znode: When znodes are constructed, the ZooKeeper can be asked to append an increasing counter to the path's end. The parent znode's counter is unique. Sequential nodes can be either persistent or ephemeral.