Server working status under Zookeeper
The server has four states, namely LOOKING, FOLLOWING, LEADING, and OBSERVING.
(1) LOOKING: Look for Leader status. When the server is in this state,
it will think that there is no leader in the current cluster, so it needs to enter the leader election state.
(2) FOLLOWING: Follower status. Indicates that the current server role is Follower.
(3) LEADING: Leader status. Indicates that the current server role is Leader.
(4) OBSERVING: Observer status. Indicates that the current server role is Observer