Re: [autofs] [RFC] Towards a Modern Autofs

From: Mike Waychison
Date: Wed Jan 07 2004 - 11:23:28 EST


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H. Peter Anvin wrote:
> Tim Hockin wrote:
>
>>On Tue, Jan 06, 2004 at 02:06:34PM -0800, H. Peter Anvin wrote:
>>
>>>
>>>First of all, I'll be blunt: namespaces currently provide zero benefit
>>>in Linux, and virtually noone uses them. I have discussed this with
>>>Linus in the past, and neither one of us see namespaces as being worth
>>
>>Let's get rid of them, then. Make life that much easier.
>>
>
>
> That's what the Linux community is doing, de facto. The Linux userspace
> simply is not set up to handle namespaces, and the autofs daemon is no
> exception. Consider such a simple thing as /etc/mtab - /proc/mounts
> which is necessary for most of the mount(8) functionality to work. It
> doesn't support namespaces and really cannot be made to.
>
> namespace support in Linux is at the best a far-off future goal. It is
> one thing to put in infrastructure, especially since it has some other
> nice benefits; it's another thing to revamp all of userspace to use it;
> it's nowhere close and autofs is no exception.
>

This is clearly not 'all of userspace'. Autofs is an exception. As is
/etc/mtab. The way I see it, automounting is a 'mount facility', as are
namespaces. The two should be made to work together. Yes, mount(8)
should probably be fixed one way or another as well due to /etc/mtab
breakage. Why? Because it too is a mount facility.

There are a couple problems inherent with namespaces. Most of these are
mount facilities that are broken such as mentioned above. They *should*
be fixed to work nicely.

Other parts of userspace get confused with namespaces, eg: cron and atd.
These programs clearly need infrastructure added that somehow allows
for arbitrary namespace joining/saving. If you have suggestions for how
we can solve this issue, please do let me know. I'm stumped :\ I'd be
more than happy to discuss this with you.

One not-so-far fetched approach would be to associate cron/at jobs with
automount configurations so that a namespace can be re-constructed at
runtime.


--
Mike Waychison
Sun Microsystems, Inc.
1 (650) 352-5299 voice
1 (416) 202-8336 voice
mailto: Michael.Waychison@xxxxxxx
http://www.sun.com

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NOTICE: The opinions expressed in this email are held by me,
and may not represent the views of Sun Microsystems, Inc.
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