[nycbug-talk] rc.conf / rc'ng hacking

[Charles Sprickman]

On Oct 13, 2011, at 2:59 PM, Isaac Levy wrote:

> On Oct 13, 2011, at 2:53 PM, Charles Sprickman wrote:
> 
>>> - The mfsroot bit:
>> 
>> Just a quick pointer in case you're not aware of it - mfsbsd might be helpful as it's already got many of the basics in doing a remote install/upgrade handled.  http://mfsbsd.vx.sk/  It's based on "depenguinator".  I use it in combination with PXE booting, but that's not the only option.
>> 
>> Charles
> 
> Quick question to clarify: this is still a fairly risky procedure, no?  Some partition on the machine has to be stable enough to persist the mfsroot for reboot/install, right?

My use case is totally different, but IIRC you can use this similar to the original depenguinator tool on a running system.  It is risky - there's no turning back once you dd the image to the drive.

I just noticed that it now has a section in the handbook:

http://www.freebsd.org/doc/en/articles/remote-install/preparation.html

> I've never put mfsroot and bare-metal upgrades/installs in the same thought before... so this is both intriguing and scary :)

I'm really happy with mfsbsd here - it's used for two things.  It's available as sort of a "livefs" rescue tool that supports ZFS on root and has all the tools needed if you need to boot a box and roll back to a known good snapshot, and it's also our default installer for new or recycled hardware.  We use PXE to boot it and then use a slightly modified version of mm's zfsinstall script (included in mfsbsd) to do the install.  It's very easy to add additional packages to the mfsbsd image as well if you need any custom tools.  We do have remote console (but not kvm) access and that's needed to toggle between network or hdd booting in the bios.  We keep multiple mfsbsd images around too - both for different FBSD versions and for i386 and amd64.  Toggling between them simply requires an edit in dhcpd.conf on the dhcp server.

Oh, it's also handy for pre-upgrade testing - it's a nice non-destructive way to verify that whatever new version of FreeBSD we're toying with at the very least boots and can go multi-user without wiping anything.  It's currently one of my favorite hammers.

Charles

> Rocket-
> .ike
> 
>