Every node in a ZooKeeper tree is referred to as a znode

Znodes maintain a stat structure that include, Version numbers, ACL ,Timestamp, Data length

Version number − Every znode has a version number, which means every time the data associated with the znode changes, its corresponding version number would also increased.

(ACL) − ACL is basically an authentication mechanism for accessing the znode. It represents read and write permisions on znode.




Timestamp − Timestamp represents time elapsed from znode creation and modification. It is usually represented in milliseconds.

Data length − Total amount of the data stored in a znode is the data length. You can store a maximum of 1MB of data.

Type of znodes: we have 3 types of znodes they are persistence, ephemeral and sequential.

Persistence znode is alive until they’re explicitly deleted, A znode can be deleted by calling the delete API call.

Ephemeral znodes are active until the client connection is alive. When a client gets disconnected from the ZooKeeper ensemble, then the ephemeral znodes get deleted automatically

Sequential znodes can be either persistent or ephemeral. When a new znode is created as a sequential znode, then ZooKeeper sets the path of the znode by attaching a 10 digit unique sequence number to the original name. Sequential znodes play an important role in Locking and Synchronization.


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