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From Ananth Gundabattula <agundabatt...@gmail.com>
Subject Re: Symbolic links disablement
Date Thu, 01 Jan 2015 01:09:40 GMT
Thanks for the response Colin.

On Thu, Jan 1, 2015 at 11:12 AM, Colin McCabe <cmccabe@alumni.cmu.edu>
wrote:

> As far as I know, nobody is working on this at the moment.  There are
> a lot of issues that would need to be worked through before we could
> enable symlinks in production.
>
> We never quite agreed on the semantics of how symlinks should work...
> for example, some people advocated that listing a directory should
> list the resolved names of all symlinks in it, while others argued
> that this would impose too great a performance load on clients listing
> directories with symlinks.  Similarly, some people argued that
> cross-filesystem symlinks should be banned, partly because they can't
> be optimized very effectively.
>
> Then there were a bunch of security issues.  Basically any
> higher-level software that is relying on path-based access will have
> problems with symlinks.  For example, Hive assumes that if you limit a
> user's access to just things under /home/username, then you have
> effectively sandboxed that person.  But if you can create a symlink
> from /home/username/foo to /foo, then you've effectively broken out of
> Hive's sandbox.  Since Hive often runs with elevated permissions, and
> is willing access files under /home/username with those permissions,
> this would be disastrous.  Hive is just one example, of course...
> basically we'd have to audit all software using HDFS for this kind of
> problem before enabling symlinks.
>
> You can see a list of all these issues and more at:
> https://issues.apache.org/jira/browse/HADOOP-10019.
>
> best,
> Colin
>
> On Thu, Dec 25, 2014 at 12:30 PM, Ananth Gundabattula
> <agundabattula@gmail.com> wrote:
> > Hello All,
> >
> > Happy holidays.
> >
> >
> > I was wondering if Symbolic links would be re-enabled anytime in the near
> > future ? https://issues.apache.org/jira/browse/HADOOP-10020
> >
> > I am using CDH VM and the moment I try to use the
> > FileContext.createSymlink() I get an error stating " Symbolic links not
> > supported" message ( UnsupportedOperationException ). The release notes
> > from CDH states that HADOOP-10020 is currently in the binary release.
> >
> > Is there any expected time line for this feature to be put back into the
> > main trunk ? If it is already, could anyone point me to the hadoop
> release
> > that the symbolic link has been reenabled ?
> >
> > Thanks for your time.
> >
> >
> > Regards,
> > Ananth
>

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