Cyconet Blog » xen

[selfnote] Change CD-image while (HVM) domU is running

cyco — Sun, 29 Nov 2009 15:23:15 +0000

xm list | grep <VMName>
xm block-list <VMName_Number>
xm block-detach <VMName_Number> <VMName_Vdev> -f
xm block-attach <VMName_Number> file:///iso/disk.iso \
hdc:cdrom r

New server hardware for svn.kvirc.de

cyco — Fri, 19 Jun 2009 04:15:12 +0000

Maybe some of you have noticed, svn.kvirc.de was running under heavy load recently while it was smashed by search engine crawlers.

First we tried to tweak the trac installation, which caused the heavy load, when running the spiders trough. But it turned out, that this doesn’t has the effect to recover the situation, since the trac tree is growing (with the svn tree and revisions). So the spiders have more to crawle and taking more resources away.

We checked our relations and we where lucky to find with waaf.net a sponsor for new server hardware.

Some features of our new ProLiant DL360 server we baptized ‘baikonur‘:

* Dual Core Processor
* 2 GB RAM
* Compaq Smart Array Raid Controller
* 2x 72.8 GB IBM Ultra3 10K
* 2x Gigabit Ethernet
* Integrated Lights Out

The migration was quite relaxed. svn.kvirc.de is a virtual maschine, so we did setup the new host and proudly racked it up at the bandnew hosting center of TMT Teleservice as first (sponsored) customer. The last step was to migrate the system over to the new host and change the DNS records. The outage was something about 5-10 minutes basically caused by the TTL of 600.

Looking into the Load Average I think we have enought resources for a couple of more svn revisions and search engine spiders.

That’s all, happy ircing, and happy developing.

windows in domU on etch. where is the showstopper?

cyco — Tue, 24 Apr 2007 18:29:17 +0000

Since some days I’m trying to install windows into a domU just for fun. All went fine until accessing discs. Sometime partition is not formatable, sometimes files could not read from cdrom. To be sure, it’s not the disc image, I used a fresh one from a MSDN Subscription, but it didn’t help.

Searching around on web, I found that I’m not the only one, with this issue. The common(s) seems to be etch (and AMD CPU).

I found traces of the issue at SP Team Blog, xen-users and xen-forum (german).

Maybe anybody can enlighten me?

Taking Xen guests (domU) alive via routed network

cyco — Thu, 29 Mar 2007 12:02:46 +0000

The xend config looks like this:

playground:~# grep -v ^# /etc/xen/xend-config.sxp
(network-script ‘network-bridge netdev=dummy0′)
(vif-script vif-bridge)
(dom0-min-mem 196)
(dom0-cpus 0)

Creating volume group for Xen domU (/dev/hdb2 was allready created with id 8e):

playground:~# pvcreate /dev/hdb2
Physical volume “/dev/hdb2″ successfully created
playground:~# vgcreate xen-vol /dev/hdb2
Volume group “xen-vol” successfully created
playground:~# vgscan
Reading all physical volumes. This may take a while…
Found volume group “xen-vol” using metadata type lvm2

Creating first domU:

playground:~# xen-create-image –ip 192.168.222.50 –hostname xetch.blubb.cyconet.org
General Infomation
——————–
Hostname : xetch.blubb.cyconet.org
Distribution : etch
Fileystem Type : ext3
Size Information
—————-
Image size : 4Gb
Swap size : 1024Mb
Image type : full
Memory size : 128Mb
Kernel path : /boot/vmlinuz-2.6.18-4-xen-vserver-686
Initrd path : /boot/initrd.img-2.6.18-4-xen-vserver-686
Networking Information
———————-
IP Address 1 : 192.168.222.50
Netmask : 255.255.255.0
Gateway : 192.168.222.1
Creating ext3 filesystem on /dev/xen-vol/xetch.blubb.cyconet.org-disk
Done
Installing your system with debootstrap mirror ftp://ftp.de.debian.org/debian/
Done
Running hooks
Done
No role script specified. Skipping
Creating Xen configuration file
Done
Setting up root password
Enter new UNIX password:
etype new UNIX password:
passwd: password updated successfully
All done
Logfile produced at:
/var/log/xen-tools/xetch.blubb.cyconet.org.log

Add the following to /etc/network/interfaces:

auto dummy0
iface dummy0 inet static
address 192.168.222.1
netmask 255.255.255.0
network 192.168.222.0
broadcast 192.168.222.255

Bringing up network interface, restarting xen and starting the domU:

playground:~# ifup dummy0
playground:~# /etc/init.d/xendomains stop
playground:~# /etc/init.d/xend restart
playground:~# /etc/init.d/xendomains start
playground:~# xm create xetch.blubb.cyconet.org.cfg -c
Using config file “/etc/xen/xetch.blubb.cyconet.org.cfg”.
…

If you want to autostart your domUs, you have to symlink the configfile to /etc/xen/auto:

playground:~# mkdir /etc/xen/auto/
playground:~# ln -s /etc/xen/xetch.blubb.cyconet.org.cfg /etc/xen/auto/xetch.blubb.cyconet.org.cfg

Getting started with XEN on etch

cyco — Wed, 28 Mar 2007 16:32:10 +0000

Today I thought it’s time to look deeper into the Xen hype. So I decided to install xen on etch. I followed Ganneffs recommandation

playground:~# aptitude install bridge-utils iproute \
xen-ioemu-3.0.3-1 xen-utils-3.0.3-1\
xen-linux-system-2.6.18-4-xen-vserver-686 libc6-xen

Booting the dom0 leeds me into kernel panic, cause no root device was found. Hmm … there seems to be the driver missing. Right – there wasn’t any /boot/initrd.img-2.6.18-4-xen-vserver-686.
Waldi did hint me to /var/lib/dpkg/info/linux-image-2.6.18-4-xen-vserver-686.postinst and I got my ramdisk this way:

playground:~# update-initramfs -c -t -k \
2.6.18-4-xen-vserver-686
playground:~# command -v update-grub > \
/dev/null && update-grub

After booting dom0 successfully, my serial console disappeared. After some digging around, I got the clue I need to tell xen, that there is one.
I modified /boot/grub/menu.lst:

# xenhopt=com1=115200,8n1 console=com1
..
# xenkopt=console=vga

Dom0 is running now, lets see what we can do next, maybe:

playground:~# aptitude install xen-tools