Subject: Re: [RFC][PATCH 2/4] sunrpc: Use utsnamespaces
From: Trond Myklebust <Trond.Myklebust@netapp.com>
To: Matt Helsley <matthltc@us.ibm.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>,
       Linux Containers <containers@lists.linux-foundation.org>,
       linux-nfs@vger.kernel.org,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       "J. Bruce Fields" <bfields@fieldses.org>,
       Chuck Lever <chuck.lever@oracle.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Linux Containers <containers@lists.osdl.org>,
       Cedric Le Goater <clg@fr.ibm.com>
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Organization: NetApp
Date: Tue, 06 Jan 2009 20:10:02 -0500
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On Tue, 2009-01-06 at 16:43 -0800, Matt Helsley wrote:
> On Tue, 2009-01-06 at 19:20 -0500, Trond Myklebust wrote:
> > On Tue, 2009-01-06 at 16:08 -0800, Matt Helsley wrote:
> > > IMHO This seems more incorrect than trying to use a more proximal
> > > namespace.
> > 
> > You have yet to explain why.
> 
> It's "more proximal" -- it's closer to the container that we expect to
> cause (directly or otherwise) the bulk of the RPC calls for that mount.
> If the container does not wind up sharing that mount with other
> containers then the reported node name matches. If the container winds
> up sharing the mount with other containers then at least we can learn
> which container originated the mount.
> 
> I imagine an NFS administrator trying to determine the source of a bunch
> of RPC calls. If we just report the initial namespace then that
> administrator has to do lots more digging to determine which container
> sent the calls (assuming they aren't in different network namespaces).

As I said elsewhere, the network namespaces do not matter, since we
always create the sockets via the rpciod workqueue.

> By not always reporting the initial namespace we may give the
> administrator one way to narrow down the search. Even if the reported
> node name does not perfectly match the source of all RPC traffic related
> to the mount at least the administrator gets something more specific.

The administrator would have to be running wireshark or something in
order to track the rpc calls. That's hardly a convenient interface, or a
compelling reason to add namespace info into RPC credentials. We
certainly haven't added any other information to the RPC calls in order
to allow the administrator to identify which process it originated from.

  Trond

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com
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