| commit | ea75e1f63572fc72fb8520ba8c793523047acb49 | [log] [tgz] |
|---|---|---|
| author | Mate Szalay-Beko <symat@apache.org> | Wed Apr 14 22:22:09 2021 +0530 |
| committer | Mohammad Arshad <arshad@apache.org> | Wed Apr 14 22:22:09 2021 +0530 |
| tree | e9a6aa278365ccbf478319a060526deaeb747b9a | |
| parent | 7fdadf7273f34dd0552db25a3771cf55b65e9208 [diff] |
ZOOKEEPER-4247: NPE while processing message from restarted quorum member
When a ZooKeeper server realizes that an other quorum peer was shut down (e.g. during a rolling upgrade or
rolling restart), the ServerCnxn.zkServer variable is set to null by QuorumPear.close(). This is why in the code
we usually check the zkServer variable before using it. But this check was missing in one place thus causing
NPE in NettyServerCnx.receiveMessage:
```
2021-02-08T12:42:08.229+0000 [myid:] - ERROR
[nioEventLoopGroup-4-1:NettyServerCnxnFactory$CnxnChannelHandler329]- Unexpected exception in receive
java.lang.NullPointerException: null ~[zookeeper-3.6.2.jar:3.6.2]
at org.apache.zookeeper.server.NettyServerCnxn.receiveMessage(NettyServerCnxn.java:518)
at org.apache.zookeeper.server.NettyServerCnxn.processMessage(NettyServerCnxn.java:368)
at org.apache.zookeeper.server.NettyServerCnxnFactory
$CnxnChannelHandler.channelRead(NettyServerCnxnFactory.java:326)
...
```
In this commit we add the necessary check and (after throwing an IOException) we will basically ignore the
processing of the received message when the remote ZooKeeper server is already down.
Author: Mate Szalay-Beko <symat@apache.org>
Reviewers: Enrico Olivelli <eolivelli@apache.org>, Mohammad Arshad <arshad@apache.org>
Closes #1681 from symat/ZOOKEEPER-4247 and squashes the following commits:
7b140177d [Mate Szalay-Beko] ZOOKEEPER-4247: address PR comments
b99ee986b [Mate Szalay-Beko] ZOOKEEPER-4247: address PR comments
3c8478a40 [Mate Szalay-Beko] ZOOKEEPER-4247: fix NPE happens while processing messages during quorum member restart
For the latest information about Apache ZooKeeper, please visit our website at:
and our wiki, at:
https://cwiki.apache.org/confluence/display/ZOOKEEPER
Either downloaded from https://zookeeper.apache.org/releases.html or found in zookeeper-assembly/target directory after building the project with maven.
apache-zookeeper-[version].tar.gz
Contains all the source files which can be built by running:
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mvn javadoc:aggregate
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apache-zookeeper-[version]-bin.tar.gz
Contains all the jar files required to run ZooKeeper
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As of version 3.5.5, the parent, zookeeper and zookeeper-jute artifacts are deployed to the central repository after the release is voted on and approved by the Apache ZooKeeper PMC:
https://repo1.maven.org/maven2/org/apache/zookeeper/zookeeper
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