[jira] [Commented] (HADOOP-10755) Support negative caching of user-group mapping

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-10755?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14044944#comment-14044944 ] 

Hadoop QA commented on HADOOP-10755:
------------------------------------

{color:green}+1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12652521/HDFS-5369.000.patch
  against trunk revision .

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:green}+1 tests included{color}.  The patch appears to include 1 new or modified test files.

    {color:green}+1 javac{color}.  The applied patch does not increase the total number of javac compiler warnings.

    {color:green}+1 javadoc{color}.  There were no new javadoc warning messages.

    {color:green}+1 eclipse:eclipse{color}.  The patch built with eclipse:eclipse.

    {color:green}+1 findbugs{color}.  The patch does not introduce any new Findbugs (version 1.3.9) warnings.

    {color:green}+1 release audit{color}.  The applied patch does not increase the total number of release audit warnings.

    {color:green}+1 core tests{color}.  The patch passed unit tests in hadoop-common-project/hadoop-common.

    {color:green}+1 contrib tests{color}.  The patch passed contrib unit tests.

Test results: https://builds.apache.org/job/PreCommit-HADOOP-Build/4178//testReport/
Console output: https://builds.apache.org/job/PreCommit-HADOOP-Build/4178//console

This message is automatically generated.

> Support negative caching of user-group mapping
> ----------------------------------------------
>
>                 Key: HADOOP-10755
>                 URL: https://issues.apache.org/jira/browse/HADOOP-10755
>             Project: Hadoop Common
>          Issue Type: Improvement
>          Components: security
>    Affects Versions: 2.2.0
>            Reporter: Andrew Wang
>            Assignee: Lei (Eddy) Xu
>         Attachments: HADOOP-10755.000.patch, HADOOP-10755.001.patch, HDFS-5369.000.patch
>
>
> We've seen a situation at a couple of our customers where interactions from an unknown user leads to a high-rate of group mapping calls. In one case, this was happening at a rate of 450 calls per second with the shell-based group mapping, enough to severely impact overall namenode performance and also leading to large amounts of log spam (prints a stack trace each time).
> Let's consider negative caching of group mapping, as well as quashing the rate of this log message.



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