Interactive ZAB — five ZooKeeper servers. Elect by highest zxid, synchronize followers up to the leader, then broadcast writes in strict zxid order. Crash the leader to trigger a new epoch.
Elect by zxid
Sync followers
Broadcast a write
Crash leader
Free play
5 ZooKeeper servers · quorum = 3 · highest zxid wins
leader
proposed
committed
crashed
1 · Election
2 · Sync
3 · Broadcast
epoch
0
1 · Elect
2 · New epoch
3 · Sync
4 · Propose + ACK
5 · Commit
Step 0 / 0
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5 ZooKeeper servers. Press
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Free play — elect, broadcast, crash
Elect & sync
Crash leader
Reset
Write:
create /a
setData /a
create /b
delete /b
leader
—
epoch
0
zxid (counter)
0
committed
0
Message log
last 2 messages