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https://issues.apache.org/jira/browse/HDFS-7146?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14160410#comment-14160410
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Allen Wittenauer commented on HDFS-7146:
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bq. For getent command, when it sees a numerical key, it thinks you are doing
reverse lookup (from id to name). That's why it returns nothing.
Something sounds broken if it is returning nothing. It should be able to map
forward and reverse if things are working correctly.
The problem with using id is that output isn't exactly portable.
bq. Unfortunately there is no corresponding one for group.
getent most definitely routes gid<->group mappings as well:
Linux:
{code}
$ getent group 1
bin:x:1:bin,daemon
$ getent group bin
bin:x:1:bin,daemon
{code}
Solaris:
{code}
$ getent group 1
other::1:root
$ getent group other
other::1:root
{code}
> NFS ID/Group lookup requires SSSD enumeration on the server
> -----------------------------------------------------------
>
> Key: HDFS-7146
> URL: https://issues.apache.org/jira/browse/HDFS-7146
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: nfs
> Affects Versions: 2.6.0
> Reporter: Yongjun Zhang
> Assignee: Yongjun Zhang
> Attachments: HDFS-7146.001.patch, HDFS-7146.002.allIncremental.patch
>
>
> The current implementation of the NFS UID and GID lookup works by running
> 'getent passwd' with an assumption that it will return the entire list of
> users available on the OS, local and remote (AD/etc.).
> This behaviour of the command is advised to be and is prevented by
> administrators in most secure setups to avoid excessive load to the ADs
> involved, as the # of users to be listed may be too large, and the repeated
> requests of ALL users not present in the cache would be too much for the AD
> infrastructure to bear.
> The NFS server should likely do lookups based on a specific UID request, via
> 'getent passwd <UID>', if the UID does not match a cached value. This reduces
> load on the LDAP backed infrastructure.
> Thanks [~qwertymaniac] for reporting the issue.
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