Apache ZooKeeper

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ZooKeeper - Data Model

== Data Model ==

The way you store data in any store is called data model. In case of zookeeper, think of data model as if it is a highly available file system with little differences.

We store data in an entity called znode. The data that we store should be in JSON format which Java script object notation.

The znode can only be updated. It does not support append operations. The read or write is atomic operation meaning either it will be full or would throw an error if failed. There is no intermediate state like half written.

znode can have children. So, znodes inside znodes make a tree like heirarchy. The top level znode is "/".

The znode "/zoo" is child of "/" which top level znode. duck is child znode of zoo. It is denoted as /zoo/duck

Though "." or ".." are invalid characters as opposed to the file system.