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Date: Mon, 26 Sep 2016 16:33:20 +0000 (UTC)
From: "Zhe Zhang (JIRA)" <jira@apache.org>
To: common-issues@hadoop.apache.org
Message-ID: <JIRA.13007628.1474907529000.665079.1474907600503@Atlassian.JIRA>
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References: <JIRA.13007628.1474907529000@Atlassian.JIRA> <JIRA.13007628.1474907529815@arcas>
Subject: [jira] [Updated] (HADOOP-13657) IPC Reader thread could silently
 die and leave NameNode unresponsive
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archived-at: Mon, 26 Sep 2016 16:33:22 -0000


     [ https://issues.apache.org/jira/browse/HADOOP-13657?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zhe Zhang updated HADOOP-13657:
-------------------------------
    Description: 
For each listening port, IPC {{Server#Listener#Reader}} is a single thread in charge of moving {{Connection}} items from {{pendingConnections}} (capacity 100) to the {{callQueue}}.

We have experienced an incident where the {{Reader}} thread for HDFS NameNode died from runtime exception. Then the {{pendingConnections}} queue became full and the NameNode port became inaccessible.

In our particular case, what killed {{Reader}} was a NPE caused by https://bugs.openjdk.java.net/browse/JDK-8024883. But in general, other types of runtime exceptions could cause this issue as well.

We should add logic to either make the {{Reader}} more robust in case of runtime exceptions, or at least treat it as a FATAL exception so that NameNode can fail over to standby, and admins get alerted of the real issue.

  was:
For each listening port, IPC {{Server#Listener#Reader}} is a single thread in charge of moving {{Connection}} items from {{pendingConnections}} (capacity 100) to the {{callQueue}}.

We have experienced an incident where the {{Reader}} thread for HDFS NameNode died from run time exception. Then the {{pendingConnections}} queue became full and the NameNode port became inaccessible.

In our particular case, what killed {{Reader}} was a NPE caused by https://bugs.openjdk.java.net/browse/JDK-8024883. But in general, other types of runtime exceptions could cause this issue as well.

We should add logic to either make the {{Reader}} more robust in case of runtime exceptions, or at least treat it as a FATAL exception so that NameNode can fail over to standby, and admins get alerted of the real issue.


> IPC Reader thread could silently die and leave NameNode unresponsive
> --------------------------------------------------------------------
>
>                 Key: HADOOP-13657
>                 URL: https://issues.apache.org/jira/browse/HADOOP-13657
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: ipc
>            Reporter: Zhe Zhang
>            Priority: Critical
>
> For each listening port, IPC {{Server#Listener#Reader}} is a single thread in charge of moving {{Connection}} items from {{pendingConnections}} (capacity 100) to the {{callQueue}}.
> We have experienced an incident where the {{Reader}} thread for HDFS NameNode died from runtime exception. Then the {{pendingConnections}} queue became full and the NameNode port became inaccessible.
> In our particular case, what killed {{Reader}} was a NPE caused by https://bugs.openjdk.java.net/browse/JDK-8024883. But in general, other types of runtime exceptions could cause this issue as well.
> We should add logic to either make the {{Reader}} more robust in case of runtime exceptions, or at least treat it as a FATAL exception so that NameNode can fail over to standby, and admins get alerted of the real issue.


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