Glenn: catchg

2011-10-21T21:22:15Z

catchg

Glenn: +cat

2011-10-21T19:19:31Z

+cat

Fluor: quick transcript of an openvz to linux-vserver migration

2008-08-12T13:19:01Z

quick transcript of an openvz to linux-vserver migration

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So, you've repeatedely heard that [http://openvz.org/ OpenVZ] was hip, better than [http://linux-vserver.org/ Linux-Vserver] even, and thought you'd give it a try? So did we! However, you weren't as pleased as you were supposed to be, and kept thinking back about how Linux-Vserver was cool for you? Well, if that's your case too, here's how we moved back to Linux-Vserver in a few simple keystrokes.

== System info ==

=== Kernels ===

We are running [http://debian.org/ Debian GNU/Linux], in its testing flavour (pre-release Lenny, frozen package base). For OpenVZ, we were using [http://packages.debian.org/sid/linux-image-2.6.26-1-openvz-686 Debian kernel 2.6.26 with OpenVZ patches]. For Linux-Vserver, we are using [http://packages.debian.org/lenny/linux-image-2.6.25-2-vserver-686 Debian kernel 2.6.25 with Linux-Vserver patches].

=== Paths ===

We created our OpenVZ CTs under ''/srv/vps/$VEID/{private,root}/'', and our vservers under ''/srv/vservers/''.

== Migrating ==

=== Copying data ===

After rebooting under the -vserver kernel, here's how we migrated each VPS, using the 'rsync method':

<pre>
[sudo] vserver $vname build -m rsync \
--hostname $vhostname \
--interface $interface:$ip \
--context $ctx -- \
--source /srv/vps/$veid/private/ -o -va
</pre>

So, for migrating an OpenVZ CT named [http://en.wikipedia.org/wiki/Seitan 'seitan'] using '192.168.66.6' on 'eth0', in context '666', the command would look like:

<pre>
sudo vserver seitan build -m rsync \
--hostname seitan \
--interface eth0:192.168.66.6/24 \
--context 666 -- \
--source /srv/vps/seitan/private/ -o -va
</pre>

Note the trailing ''-o -va'', which allows us to follow rsync as it goes.

=== Fix daemons ===

When rsync is done, we can't start our vservers yet, because some of the system daemons that OpenVZ allows are not compatible with a Vserver environment. Let's remove their startup links, then!

To do so, let's chroot into our freshly migrated vserver:

<pre>sudo chroot /srv/vservers/seitan/</pre>

Once inside, let's unlink all the undesired daemons:

<pre>
for undesired in klogd hwclock.sh setserial urandom networking umountfs halt reboot ;
do update-rc.d -f $undesired remove ;
done
</pre>

=== Enjoy ===

Let's log out of the chroot, and start our vserver!

<pre>
exit
sudo vserver seitan start
</pre>

It should work fine, provided some of your daemons don't depend upon bind mounts from host, which then need to be integrated into the fstab for each of your vservers.

Welcome back!

← Older revision		Revision as of 21:22, 21 October 2011
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	Welcome back!		Welcome back!

−	[[Category:~~Documentation~~]]	+	[[Category:Migration]]

← Older revision		Revision as of 19:19, 21 October 2011
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	Welcome back!		Welcome back!
		+
		+	[[Category:Documentation]]

Migrating from OpenVZ to Linux-Vserver - Revision history

Glenn: catchg

Glenn: +cat

Fluor: quick transcript of an openvz to linux-vserver migration