Subject: Re: devfs, was Re: FreeBSD 5/6/7 kernel emulator for NetBSD 2.x
To: None <wrstuden@NetBSD.org>
From: M. Warner Losh <email@example.com>
Date: 10/29/2005 00:11:57
In message: <20051027224153.GD16197@netbsd.org>
Bill Studenmund <wrstuden@NetBSD.org> writes:
: I do see an advantage to having multiple /dev mounts so that chroot
: environments can have devices. I think that came up as a MUST last time we
: hashed this out.
I think it is a must. Let me share some experience I had when FreeBSD
transitioned to using devfs from the traditional method. I don't
share this to show FreeBSD is better or worse than anything, but to
give a concrete example of why it is needed, and some of the pitfalls
that I didn't anticpate up front.
My company builds FreeBSD based systems. We have a build process that
builds a chroot, then builds the image/binaries in the chroot to
ensure that there is no host contamination possible. We quickly
discovered (and fixed) that you have to mount a devfs instance inside
the jail, or you get weird errors. Lots of stuff just works w/o real
devs, but enough doesn't that you really need to mount it. There were
also issues about mounting devfs on top of a amd automount, but those
were also resolved.
If you have a lot of chroots, then the chroot command you used to use
might have to change to into a mount + chroot command to get the