Jaervosz' burrow

Coming Underground

2009-12-15 15:35, by jaervosz, Categories: General, Gentoo Tips, Gentoo, Universe/English

I just managed to reboot one of the Xen servers I still admin, just by creating another domain:-/

Running with old versions of xen-sources results in problems as seen above and with newer udev versions. For reference to the Gentoo Xen users out there I'm posting this.

If you see errors like:
* Mounting proc at /proc ... [ ok ] * Mounting sysfs at /sys ... [ ok ] * Your kernel is too old to work with this version of udev. * Current udev only supports Linux kernel 2.6.25 and newer. * Could not create /dev/pts! * Checking root filesystem ...Failed to open the device '/dev/sda1': No such file or directory * Filesystem couldn't be fixed :( [ !! ] Give root password for maintenance (or type Control-D to continue):

You've probably upgraded to a version of udev that actively refuses to boot with your old Xen kernel. Normally my workaround is to mask all udev versions greater than 141 (the fix being a migration to a supported supported virtualization technology).

Also make sure that you have the old version of /etc/init.d/udev-mount, otherwise your system will refuse to boot. Perhaps it's possible to just hack around this limitation in the udev-mount init script but I haven't really bothered to check. There might be a better official fix that I haven't found yet though....

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Comment from: Jim T [Visitor]

Is Xen still using 2.6.11? Do they have any plans to rectify this? I'm sure Xen isn't end-of-life ...

2009-12-15 @ 16:34

Comment from: Aaron [Visitor]

The other migration path is to move towards the pv_ops dom0 branch that tracks the mainline kernel. My understanding is that it and Xen 4.0 should be landing in early 2010.

2009-12-15 @ 16:41

Comment from: jaervosz [Member]

To be honest I haven't bothered with their upgrade path. I'm heading for KVM in the mainline kernel, I'm just waiting for some proper init scripts....

2009-12-15 @ 16:43

Comment from: nitro322 [Visitor] · http://www.legroom.net/

I don't understand why Gentoo insists on staying with 2.6.18 for xen-sources, but Andrew Lyonan maintains an unofficial and much more up-to-date kernel here:

http://code.google.com/p/gentoo-xen-kernel/

I've been using this on my Xen server for a while it it works well, plus you won't need to worry about the udev hassles described here.

2009-12-15 @ 17:27

Comment from: Kevin Bowling [Visitor]

· http://www.kev009.com/

Not sure what you mean by migrate to KVM. This seems to be a common misconception.

There is a very large pool of very useful servers that CANNOT run KVM due to not having proper CPUs. This includes powerful first and second generation Opterons and many 32- and 64-bit Xeon CPUs before the Core microarchitecture.

It is naive to assume everybody can afford to upgrade to expensive new machines or should put their current high end hardware in a landfill because KVM is the hot new thing. Xen works very well, so please stop spreading FUD. Gentoo is broken, not Xen.

2009-12-15 @ 17:44

Comment from: jaervosz [Member]

@nitro322: thanks for the link, might look into that.

@Kevin Bowling: Certainly not intended as FUD just as a help for those using stock Gentoo xen-sources. I just clarified the post a bit. If people want to use Xen fine with me, it would be even greater if we had updated xen-sources in the tree. I'm wondering why the above link is not in Portage or Sunrise though....

2009-12-15 @ 18:15

Comment from: jens [Visitor]

I have to second nitros suggestion, Andrew Lyonan´s kernel ebuild works like a charm.

2009-12-18 @ 17:59

Comment from: jaervosz [Member]

I guess I'll take the updated Xen kernel for a spin at work.

2009-12-18 @ 21:49

Comment from: Raul [Visitor]

Oh awesome!
Thanks for the link. I was about to move to the pv_ops but I dunno if I trust it yet. I think i'll stick with the patched kernel for now.

Thanks!

2009-12-18 @ 23:25

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