Hi Kai,

1. To the best of my knowledge, you can only use one group mapping service
at a time. In order to do what you're suggesting, you'd have to write a
customized group mapping service.

2. Currently multiple ADs are not supported, but it's certainly an
improvement that could be made.

3. The LdapGroupsMapping already supports OpenLDAP. It's pretty heavily
configurable for the purpose of supporting multiple types of LDAP
implementations. The defaults just happen to be geared towards Active
Directory.

Thanks,
Natty

On Mon, Oct 15, 2012 at 8:07 PM, Zheng, Kai <kai.zh...@intel.com> wrote:

>  Hi Koert & Harsh,****
>
> ** **
>
> Regarding LdapGroupsMapping, I have questions:****
>
> **1.      **Is it possible to use ShellBasedUnixGroupsMapping for Hadoop
> service principals/users, and LdapGroupsMapping for end user accounts?****
>
> In our  environment, normal end users (along with their groups info) for
> Hadoop cluster are from AD, and for them we should use the ldap mapping;**
> **
>
> but for hdfs/mapred service principals, the default shell based one is
> enough, and we don’t want to create the user/group entries in AD just for
> that.****
>
> **2.      **Can we support multiple ADs? Hadoop users might come from
> more than ONE AD in big org.****
>
> **3.      **Is there any technical  issue not to support LDAPs like
> OpenLDAP? In my understanding, one possible difficulity might be that it’s
> not easy to extract common****
>
> group lookup mechanism with common filters/configurations both for AD and
> OpenLDAP like, right?****
>
> ** **
>
> I’m wondering if these are just limits for current implementation, and if
> so if we need to improve that. Might the community has already been going
> for that?****
>
> ** **
>
> Thanks****
>
> Kai****
>
> ** **
>
> *From:* Ivan Frain [mailto:ivan.fr...@gmail.com]
> *Sent:* Tuesday, October 09, 2012 2:46 PM
> *To:* user@hadoop.apache.org
> *Subject:* Re: Secure hadoop and group permission on HDFS****
>
> ** **
>
> Hi Koert,****
>
> ** **
>
> Another option is to use the LdapGroupsMapping which picks up the group
> membership from a LDAP directory.****
>
> You can find more details on the JIRA issue:
> https://issues.apache.org/jira/browse/HADOOP-8121****
>
> Up to now, it is available for ActiveDirectory and released in
> hadoop-2.0.0-alpha and next releases.****
>
> You can easily apply the patch on a 0.23.1, I already did that and it
> works well.****
>
> ** **
>
> OpenLdap with POSIX groups is not yet supported by this patch, it was
> tailored for ActiveDirectory.****
>
> ** **
>
> ** **
>
> BR,****
>
> Ivan****
>
> ** **
>
> 2012/10/9 Harsh J <ha...@cloudera.com>****
>
> Koert,
>
> If you use the org.apache.hadoop.security.ShellBasedUnixGroupsMapping
> class (via hadoop.security.group.mapping), then yes the NameNode's
> view of the local unix groups (and the primary group) of the user is
> the final say on what groups the user belongs to. This can be relied
> on - but note that HDFS uses BSD style semantics when it comes to
> groups and when creating directories/files, the parent directory
> groups are inherited automatically unless altered after creation.****
>
>
> On Tue, Oct 9, 2012 at 2:30 AM, Koert Kuipers <ko...@tresata.com> wrote:
> > With secure hadoop the user name is authenticated by the kerberos server.
> > But what about the groups that the user is a member of? Are these simple
> the
> > groups that the user is a member of on the namenode machine?
> > Is it viable to manage access to files on HDFS using groups on a secure
> > hadoop cluster?
> >
>
>
> ****
>
> --
> Harsh J****
>
>
>
> ****
>
> ** **
>
> --
> Ivan Frain
> 11, route de Grenade****
>
> 31530 Saint-Paul-sur-Save****
>
> mobile: +33 (0)6 52 52 47 07****
>
> ** **
>
> ** **
>

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