Hello,

This warning typically means that your user is not defined/visible within the 
host OS for all nodes in the Hadoop cluster.  The Hadoop code determines a 
user's set of group memberships by consulting the underlying OS.  If the user 
is unknown at the OS layer, then Hadoop sees an empty set of group memberships 
and logs this warning.

The typical fix is to make sure the user is defined at all nodes in the 
cluster, such as by running useradd.  For large production clusters, 
integrating with a centralized LDAP server obviously makes this a lot more 
manageable.

Alternatively, you could choose to ignore the warning.  If your application is 
not dependent on group memberships for anything (such as HDFS file permissions 
granting access to a group), then that might be acceptable for your use case.

Chris Nauroth
Hortonworks
http://hortonworks.com/


From: xeonmailinglist-gmail 
<[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Date: Thursday, April 23, 2015 at 3:04 AM
To: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Subject: UserGroupInformation: No groups available for user


I am trying to submit a remote job in mapreduce, but I get the error [1].
I even have set in hdfs-site.xml in the remote hadoop the content [2], and 
changed permissions [3], but the problem remains.

How should I get rid of this problem?

2015-04-23 05:57:35,648 WARN org.apache.hadoop.security.UserGroupInformation: 
No groups available for user xeon


    <property>
        <name>dfs.web.ugi</name>
        <value>xeon,webuser,webgroup</value>
    </property>


[3]

2041  hdfs dfs -chown -R xeon:supergroup /user/xeon
2045  hdfs dfs -chown -R xeon:supergroup /tmp/hadoop-yarn/staging/xeon/
2039  hdfs dfs -chmod -R 777 /user/xeon
2053  hdfs dfs -chmod -R 777 /tmp/hadoop-yarn/staging/xeon


​

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