[HADOOP-13965] Groups should be consistent in using default group mapping class

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha2
• Fix Version/s: 3.0.0-alpha2, 2.10.2
• Component/s: security
• Hadoop Flags: Reviewed
• Assignee: Yiqun Lin
• Reporter: Yiqun Lin
• Created: 10/Jan/17 11:31
• Updated: 21/Jan/21 17:46
• Resolved: 19/Jan/17 01:46

Description

Groups.java

      public Groups(Configuration conf, final Timer timer) {
       impl = 
      ReflectionUtils.newInstance(
          conf.getClass(CommonConfigurationKeys.HADOOP_SECURITY_GROUP_MAPPING, 
                        ShellBasedUnixGroupsMapping.class, 
                        GroupMappingServiceProvider.class), 
          conf);
      ...
}

The default value of setting hadoop.security.group.mapping is different in code and config file. In file core-default.xml, it uses the class JniBasedUnixGroupsMappingWithFallback and this should be the true value.

<property>
  <name>hadoop.security.group.mapping</name>
 <value>org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback</value>
  <description>
    Class for user to group mapping (get groups for a given user) for ACL.
    The default implementation,
    org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback,
    will determine if the Java Native Interface (JNI) is available.....
  </description>
</property>