[jira] [Commented] (HDFS-7146) NFS ID/Group lookup requires SSSD enumeration on the server

["Brandon Li (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HDFS-7146?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14153952#comment-14153952 ] 

Brandon Li commented on HDFS-7146:
----------------------------------

Thank you, [~yzhangal] for uploading the patch.
In general the patch looks good. One question I have is: do we still want to load a bunch of name-id mapping when the IdUserGroup object is initialized? the initial  loading could cache many useless user/group accounts.


> 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
>
>
> 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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