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+ <title>Petter Reinholdtsen: Migrating Xen virtual machines using LVM to KVM using disk images</title>
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+ <div class="title">
+ <h1>
+ <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
+
+ </h1>
+
+ </div>
+
+
+ <div class="entry">
+ <div class="title">Migrating Xen virtual machines using LVM to KVM using disk images</div>
+ <div class="date">2010-11-22 11:20</div>
+ <div class="body">
+<p>Most of the computers in use by the
+<a href="http://www.skolelinux.org/">Debian Edu/Skolelinux project</a>
+are virtual machines. And they have been Xen machines running on a
+fairly old IBM eserver xseries 345 machine, and we wanted to migrate
+them to KVM on a newer Dell PowerEdge 2950 host machine. This was a
+bit harder that it could have been, because we set up the Xen virtual
+machines to get the virtual partitions from LVM, which as far as I
+know is not supported by KVM. So to migrate, we had to convert
+several LVM logical volumes to partitions on a virtual disk file.</p>
+
+<p>I found
+<a href="http://searchnetworking.techtarget.com.au/articles/35011-Six-steps-for-migrating-Xen-virtual-machines-to-KVM">a
+nice recipe</a> to do this, and wrote the following script to do the
+migration. It uses qemu-img from the qemu package to make the disk
+image, parted to partition it, losetup and kpartx to present the disk
+image partions as devices, and dd to copy the data. I NFS mounted the
+new servers storage area on the old server to do the migration.</p>
+
+<pre>
+#!/bin/sh
+
+# Based on
+# http://searchnetworking.techtarget.com.au/articles/35011-Six-steps-for-migrating-Xen-virtual-machines-to-KVM
+
+set -e
+set -x
+
+if [ -z "$1" ] ; then
+ echo "Usage: $0 <hostname>"
+ exit 1
+else
+ host="$1"
+fi
+
+if [ ! -e /dev/vg_data/$host-disk ] ; then
+ echo "error: unable to find LVM volume for $host"
+ exit 1
+fi
+
+# Partitions need to be a bit bigger than the LVM LVs. not sure why.
+disksize=$( lvs --units m | grep $host-disk | awk '{sum = sum + $4} END { print int(sum * 1.05) }')
+swapsize=$( lvs --units m | grep $host-swap | awk '{sum = sum + $4} END { print int(sum * 1.05) }')
+totalsize=$(( ( $disksize + $swapsize ) ))
+
+img=$host.img
+#dd if=/dev/zero of=$img bs=1M count=$(( $disksize + $swapsize ))
+qemu-img create $img ${totalsize}MMaking room on the Debian Edu/Sqeeze DVD
+
+parted $img mklabel msdos
+parted $img mkpart primary linux-swap 0 $disksize
+parted $img mkpart primary ext2 $disksize $totalsize
+parted $img set 1 boot on
+
+modprobe dm-mod
+losetup /dev/loop0 $img
+kpartx -a /dev/loop0
+
+dd if=/dev/vg_data/$host-disk of=/dev/mapper/loop0p1 bs=1M
+fsck.ext3 -f /dev/mapper/loop0p1 || true
+mkswap /dev/mapper/loop0p2
+
+kpartx -d /dev/loop0
+losetup -d /dev/loop0
+</pre>
+
+<p>The script is perhaps so simple that it is not copyrightable, but
+if it is, it is licenced using GPL v2 or later at your discretion.</p>
+
+<p>After doing this, I booted a Debian CD in rescue mode in KVM with
+the new disk image attached, installed grub-pc and linux-image-686 and
+set up grub to boot from the disk image. After this, the KVM machines
+seem to work just fine.</p>
+</div>
+
+ <div class="tags">Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>.</div>
+
+ </div>
+
+
+
+
+
+
+<div id="sidebar">
+
+<h2>Archive</h2>
+<ul>
+
+<li>2010
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (9)</a></li>
+
+</ul></li>
+
+<li>2009
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
+
+</ul></li>
+
+<li>2008
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
+
+</ul></li>
+
+</ul>
+
+
+
+<h2>Tags</h2>
+<ul>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (12)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (10)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (41)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (49)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (70)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (11)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (5)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (4)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (10)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (90)</a></li>
+
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+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (18)</a></li>
+
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+
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+
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+
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+
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+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (3)</a></li>
+
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+
+</ul>
+
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+</html>
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