write operations in ZooKeeper are atomic and durable. There is the guarantee of a successful
write operation if it has been written to persistent storage on a majority of ZooKeeper's servers. However, the eventual consistency model of ZooKeeper permits reads to log the latest state of the ZooKeeper service, and the
sync operation allows a client to be up-to-date with the most recent state of the ZooKeeper service.
read operations in znodes, such as
getData, allow watches to be set on them. On the other hand, the watches triggered by znode's
write operations, such as
setData ACL operations do not participate in watches.
The following are the types of watch events that might occur during a znode state change: