Date: Fri, 1 Mar 2002 16:08:29 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Robert Watson <rwatson@FreeBSD.ORG>, Glenn Gombert <ggombert@imatowns.com>, Cliff Sarginson <csfbsd@raggedclown.net>, current@FreeBSD.ORG Subject: Re: more -current testers Message-ID: <200203020008.g2208TH47729@apollo.backplane.com> References: <Pine.NEB.3.96L.1020301183610.97153A-100000@fledge.watson.org>
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There is a 'diskless' manual page, /usr/src/share/man/man8/diskless.8.
It is somewhat out of date and it would be nice if it had a dhcpd.conf
example. It would be great if someone did a major rewrite of it.
-Matt
Matthew Dillon
<dillon@backplane.com>
:On Fri, 1 Mar 2002, Glenn Gombert wrote:
:
:> I have spent several months figuring how to do diskless mounts for
:> test kernels, run debuggers from serial terminals and do remote kernel
:> debugging with gdb, and spent lots and lots of time doing is as well.
:> Some 'up to date' "How To's" are really needed to support this kind of
:> debugging and testing efforts, the material in the FreeBSD manual is
:> helpful to a point, but much 'key' information on such subjects is just
:> not there and has to be dug out of mailing list archives and just
:> sending e-mails to various people who have done such things in the past
:> and ask for help, taking up their time...which could be saved with some
:> up-to-date documentation :))
:
:If you want to start writing that stuff up for inclusion in the FreeBSD
:Handbook or some related location, I'd be happy to review it for content,
:since I use what sounds like a very similar development environment.
:
:In my environment, I have a central build and file server, and then a
:series of network booted crash machines. The central server has two
:ethernet cards, one going to the "outside world" for some definition of
:outside, and the other a dedicated development network. The server runs a
:DHCP server for the development network, a TFTP server to server copies of
:pxeboot(8) for the development network, and NFS exports of a /usr/netboot
:tree where I store the diskless roots, kernels, et al for the crash boxes.
:Typically, I'll use
:
: /usr/netboot/crash1.decoverly.watson.org
: /usr/netboot/crash2.decoverly.watson.org
:
:as the roots for each environment, point tftpd(8) at /usr/netboot as its
:root, and appropriately configure the DHCP server to point each host at
:the right root directory to pull down pxeboot, and for its later NFS root.
:I also hook up serial consoles for each box; currently working on remote
:power.
:
:Depending on what I'm working on, I may use the crash boxes in different
:ways. Frequently, I'll boot them entirely from the network, with a
:complete installkernel and installworld into their roots under
:/usr/netboot. However, if I'm doing filesystem related work, I may do
:more disk-centric installation mechanisms. I haven't tried the modified
:install floppy trick.
:
:Some cute tricks..
:
:newfs is faster than fsck. If you need to use local filesystems on the
:box, and don't care about persistent data, it's a lot faster to newfs the
:file systems than do the file system check :-). If that's true for even
:one file system, it's an improvement. Sometimes I wonder if that wouldn't
:be a good change for all installs :-).
:
:Some boxes appear to have broken serial break support. There's a kernel
:option for an alternative break key that can be quite useful. I have this
:problem with two SGI boxes I'm using for various TrustedBSD-related
:things.
:
:I can configure the hard disks as dump devices, and by swapping back and
:forth between kernels, I can pull the dump over to the development server.
:It may be you can dump over the network, but perhaps not :-).
:
:It's possible to replace the kernel out from under a machine while still
:crashing/dumping/rebooting. This can dramatically reduce the
:develop/compile/install/test/crash/repeat cycle by coallescing the test
:and crash bits with the other bits, since you can compile while still
:testing or crashing.
:
:If you have multiple machines, you can easily allocate them to various
:projects, etc, etc. I have a couple of scripts that help populate a
:system the first time, by chrooting and running cap_mkdb, pwd_mkdb, etc,
:etc. I generally also tweak the rc.diskless[12] scripts a bit based on
:what I need. I also tend to enable remote root login and empty passwords
:for the crash box in sshd_config so that I can login into the machines
:once they come up very easily.
:
:Occasional PXE bugs can be very frustrating. Some machines I've used have
:no problem loading pxeboot from a different machine than the DHCP server.
:A couple of others ignore the server specification in the DHCP response
:and insist on trying to tftp pxeboot from the DHCP server.
:
:Robert N M Watson FreeBSD Core Team, TrustedBSD Project
:robert@fledge.watson.org NAI Labs, Safeport Network Services
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