Categories
advocacy

XenSource ‘Simply Virtualize’

The XenSource ‘Simply Virtualize‘ tour made it’s way to NZ this week, with a 3 hour set of presentations at Microsoft House yesterday afternoon. We had a good catchup with John Glendenning from XenSource on Monday, but I can’t talk about most of that.

The presenters at the event were XenSource, Sun Microsystems, Microsoft, Platespin and ExpresData hosted the event. The tour seems to be done in conjunction with IBM elsewhere, but was done with Sun here in NZ.

John Glendenning from XenSource gave a brief introduction to XenSource and Xen Enterprise, and also some points about where development is heading. One point is the planned interoperability with Veridian, the Microsoft virtualization stack. The Microsoft presentation followed, which focussed entirely on MS’s various virtualization technologies – presentation, application, server, etc. It had some interesting aspects, but was a tiny bit out of place I thought.  Sun had a good set of slides on their AMD-V platforms, including their new blade infrastructure which will support opteron, xeon (when they come out later in the year) and ultrasparc blades. Platespin then gave a fairly quick, but comprehensive overview of their P2V / V2V and capacity planning and management tools. James Johnstone from ExpressData finished up with a demo of Xen Enterprise and Windows XP guests running on a SunFire x4200 M2.

Things that I got from the various presentations:

  • Microsoft’s SoftGrid Application Virtualization software suite looks damn useful, and I can think of at least one site we could have used it this year.
  • Sun are coming out with Xeon-based servers soon, as well as AMD’s quad-core range being on the horizon
  • Sun have a blade range that has a fully modular IO system – the PCI infrastructure is abstracted away from the blade.
  • Platespin’s PowerConvert and PowerRecon products look very useful, and they are aggresively adding new features.

From Platespin’s presentation and some of the points that MS came out with it is very clear that the virtualization technology you choose for server virtualization is definitely not the final decision to make, nor should it be. The virtualization ecosystem is massive already – mostly due to the number of ISVs VMWare has on board. These ISVs are now targetting Xen Enterprise as a platform as well, and are bringing their already mature technology to focus on the alternative platforms. This gives Xen Enterprise quite a bit of credibility, as the management tools don’t have to be rebuilt – vendors like Platespin, Leostream, Mountain View Data, Marathon etc can target Xen with relative ease.

Categories
NSP WLUG

Feisty Fawn and Software RAID

It turns out there’s a race condition in Feisty Fawn, which can cause software RAID sets to not be set up on boot. This is problematic if you have your root partition on software RAID

Bug #75681 discusses this in some detail, although there are several suggestions on how to fix it.

I first hit this bug on a local machine, then had to the same upgrade on a machine in a different country. Needless to say I wanted to get it right. I’m archiving my notes here as I’m sure I’ll need them eventually. This race condition has probably already been fixed in Feisty, but it’s not worth risking on a remote machine.

First of all, there is some new management involved in setting up software RAID under feisty, so you need to make sure you read the documentation for the mdadm package. Every time an initramfs is generated it will generate a warning:

[code]
update-initramfs: Generating /boot/initrd.img-2.6.20-14-generic
cp: cannot stat `/etc/udev/rules.d/85-brltty.rules’: No such file or directory
W: mdadm: unchecked configuration file: /etc/mdadm/mdadm.conf
W: mdadm: please read /usr/share/doc/mdadm/README.upgrading-2.5.3.gz .
W: mdadm: no arrays defined in configuration file.
W: mdadm: falling back to emergency procedure in initramfs.
[/code]

Following those instructions, you are told to check the configuration in /etc/mdadm/mdadm.conf and compare with the output of /usr/share/mdadm/mkconf. Once you’ve done that, you can remove /var/lib/mdadm/CONF-UNCHECKED and re-run update-initramfs -u -k all to regenerate your initramfs images.

The particular race condition that I mentioned above occurs because udev hasn’t had time to stabilise before mdadm tries to create the array, which means mdadm can’t find the devices and fails. The fix suggested in the bug report is to insert udevsettle into the initramfs at an appropriate point, and recreate the initramfs images:

[code]
# echo “/sbin/udevsettle –timeout=10” >> /usr/share/initramfs-tools/scripts/init-premount/udev
# update-initramfs -u -k all
[/code]

This works, at least as of today. I don’t know if the bug is actually still a problem or not – I didn’t want to risk it./

Categories
General NSP WLUG

Debian Etch and apt-proxy issues

Debian Etch (4.0) was released on Monday, and I have to say I wasn’t at all prepared. I’ve got about 70 machines that will probably need to be upgraded to Etch at some point in the near future. I could leave some of them running sarge, but I’ll definitely have to upgrade most of these servers.

We use an apt-proxy internally, to improve apt performance. It works well, aside from a couple of bugs that cause it to lock up every now and then. While running some upgrades on out of the way servers today, I discovered that the version of apt in sarge really doesn’t play very nicely with an etch repository served by apt-proxy running on an etch server. It seems that Ubuntu is fine, and trying to update a sarge server via an apt-proxy running on an etch server is ok too.

Once the etch client has been upgraded, the etch apt-proxy works fine. So, looks like a key issue. The version of apt in sarge doesn’t have the archive security stuff in it, and has no way of checking whether the keys are intact – BUT, it still seems to care, and will timeout and eventually fail.

It turns out that installing a copy of apt from the sarge backports solves this. You’ll also need the gnupg package, but the one from sarge is OK
[code]
wget http://backports.org/debian/pool/main/a/apt/apt_0.6.46.4-0.1~bpo.1_i386.deb
wget http://backports.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2006.11.22~bpo.2_all.deb
dpkg -i *.deb
apt-get update
[/code]