Wei-Chiu Chuang created HDFS-15719: -------------------------------------- Summary: [Hadoop 3] Both NameNodes can crash simultaneously due to the short JN socket timeout Key: HDFS-15719 URL: https://issues.apache.org/jira/browse/HDFS-15719 Project: Hadoop HDFS Issue Type: Bug Affects Versions: 3.0.0 Reporter: Wei-Chiu Chuang
After Hadoop 3, we migrated Jetty 6 to Jetty 9. It was implemented in HADOOP-10075. However, HADOOP-10075 erroneously set the HttpServer2 socket idle timeout too low. We replaced SelectChannelConnector.setLowResourceMaxIdleTime() with ServerConnector.setIdleTimeout() but they aren't the same. Essentially, the HttpServer2's idle timeout was the default timeout set by Jetty 6, which is 200 seconds. After Hadoop 3, the idle timeout is set to 10 seconds, which is unreasonable for JN. If NameNodes try to download a big edit log from JournalNodes (say a few hundred MB), it is likely to exceed 10 seconds. When it happens, both NN crashes and there's no way to workaround unless you apply the patch in HADOOP-15696 to add a config switch for the idle timeout. Fortunately, it doesn't happen a lot. Propose: bump the idle timeout default to 200 seconds to match the behavior in Jetty 6. (Jetty 9 reduces the default idle timeout to 30 seconds, which is not suitable for JN) Other things to consider: 1. fsck serverlet? (somehow I suspect this is related to the socket timeout reported in HDFS-7175) 2. webhdfs, httpfs? --> we've also received reports that webhdfs can timeout. so having a longer timeout makes sense here. 2. kms? will the longer timeout cause more lingering sockets? Thanks [~zhenshan.wen] for the discussion. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org