[ZOOKEEPER-2847] Cannot bind to client port when reconfig based on old static config

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.5.3, 3.6.0
• Fix Version/s: 3.6.0
• Component/s: server
• Labels: pull-request-available
• Assignee: Yisong Yue
• Reporter: Fangmin Lv
• Created: 19/Jul/17 06:14
• Updated: 04/Oct/19 14:55
• Resolved: 01/Oct/18 04:11

Description

When started the ensemble with old static config that the server string doesn't have client port, dynamically remove and add the same server from the ensemble will cause that server cannot bind to client port, and the ZooKeeper server cannot serve client requests anymore.

From the code, we'll set the clientAddr to null when start up with old static config, and dynamic config forces to have <client port> part, which will trigger the following rebind code in QuorumPeer#processReconfig, and cause the address already in used issue.

public boolean processReconfig(QuorumVerifier qv, Long suggestedLeaderId, Long zxid, boolean restartLE) {
...
if (myNewQS != null && myNewQS.clientAddr != null
&& !myNewQS.clientAddr.equals(oldClientAddr))

{ cnxnFactory.reconfigure(myNewQS.clientAddr); updateThreadName(); }

...
}

Issue Links

• links to: GitHub Pull Request #620
• links to: GitHub Pull Request #649