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From Shashi Vishwakarma <shashi.vish...@gmail.com>
Subject Re: Get member list of group in HDFS using Java/Script
Date Sat, 20 Feb 2016 17:41:14 GMT
Thanks Chris. Information you provided is very much helpful..
On 20 Feb 2016 12:18 am, "Chris Nauroth" <cnauroth@hortonworks.com> wrote:

> Hello Shashi,
>
> HDFS itself doesn't have any knowledge of membership of users in groups.
> The user and group field of an HDFS file or directory are just arbitrary
> strings.  For consulting a user's group memberships, HDFS runs a group
> mapping provider [1].  This is pluggable, but the common case is either
> querying the underlying OS directly or querying an LDAP server.
>
> For a given username, you can check what HDFS thinks its group memberships
> are by running the "hdfs groups" command [2].  For example:
>
> > hdfs groups chris
> chris : staff everyone localaccounts _appserverusr admin _appserveradm
> _lpadmin _appstore _lpoperator _developer com.apple.access_screensharing
> com.apple.access_ssh
>
> However, there is no way to query a list of all users in a group through
> HDFS.  HDFS doesn't have a use case for this kind of query, so it doesn't
> implement one.  For that, I'd expect you'd need to query directly whatever
> your group membership infrastructure is (i.e. run the "groups" command at
> the OS layer or query an LDAP server).
>
> I hope this helps.
>
> --Chris Nauroth
>
> [1]
> http://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-hdfs/HdfsPermissionsGuide.html#Group_Mapping
> [2]
> http://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-hdfs/HDFSCommands.html#groups
>
>
> From: Shashi Vishwakarma <shashi.vish123@gmail.com>
> Date: Thursday, February 18, 2016 at 11:29 PM
> To: "user@hadoop.apache.org" <user@hadoop.apache.org>
> Subject: Get member list of group in HDFS using Java/Script
>
> Hi
>
> I need to find how many users belong to particular group in HDFS using
> Java/Script.
>
> Let's say I have a directory /user/data in HDFS and it belongs to a group
> 'abc' .
>
> I need to find how may other users belongs to 'abc' group.
>
> Can anyone suggest something.
>
> Thanks
>

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