Understand the zookeeper in zab agreement

1.zab protocol: zookeeper atomic broadcast, atomic broadcast protocol, for data consistency protocol zookeeper, reference paxos protocol implemented.
Request- 2.write> Request Processor (txn) ----> actomic broadcast-> replicationed database-> the Response
3. point of interest data consistency, accuracy unrelated data, authority, timeliness.
4.zab specific process (ordering)
@ 1. All transaction requests to the Leader
@ 2.leader monotonically increasing zxid, Broadcasting protocol
@ 3.follower processing proposals for feedback
@ 4.leader receive half of feedback, broadcast the commit
@ 5.leader as feedback