[Users] Using OpenVZ Legacy OS Templates on Virtuozzo 7 Beta

[Scott Dowdle]

Greetings,

The subject of this email might horrify the V7 developers with the ongoing development and testing of Virtuozzo 7, but there is a fairly obvious way to use OpenVZ Legacy OS Templates with Virtuozzo 7 Beta.  First, on your V7 host make sure you install all of the ez template meta-data packages:

centos-5-x86-ez-7.0.0-2.vz7.noarch
centos-6-x86_64-ez-7.0.0-1.vz7.noarch
centos-7-x86_64-ez-7.0.0-5.vz7.noarch
debian-8.0-x86_64-ez-7.0.0-2.vz7.noarch
ubuntu-14.04-x86_64-ez-7.0.0-2.vz7.noarch

The CentOS ones should already be there but not Debian and Ubuntu.

1) Create a container using the OS Template that is closest to your target OpenVZ Legacy OS Template.  Please note that CentOS 5 uses SysVinit, CentOS 6 uses Upstart, and CentOS 7 uses systemd.  Debian 8 uses systemd whereas Ubuntu uses Upstart.

2) mount your new container

3) cd into /vz/root/{ctid} and delete everything... removing all of the files that were part of the container you just created

4) Extract the contents of your target OpenVZ Legacy OS Template in the same place you just deleted everything

5) umount the container

6) Start the container

If everything went well your container will start and you'll see the normal set of processes you'd expect.  Hopefully networking is configured correctly, etc.  If so, you can use prlctl's clone parameter to make additional containers... or use the clone command with the --template flag to turn the existing container's filesystem into a new OS Template.

While that recipe is a fairly sloppy way to do it, it'll at least let us try additional container types... and even have a basis for submitting contributed OS Templates (which there isn't a process nor storage place for yet) at some point in the future.  A better way of doing it would be to make additional ez template meta-data packages... or use a manual way to create new OS Templates once the community is more familiar with the pre-created OS Template format used by V7... but we aren't quite there yet.

Using the basic recipe above, I converted a CentOS 7 container to a Fedora 22 container... and it seems to be working nicely.  I haven't tried any others yet so it may be that I was just lucky with this combination... but if anyone else tries other OpenVZ Legacy OS Templates and gets them to work, please let me know.  Feel free to email me directly if desired.

TYL,
-- 
Scott Dowdle (dowdle at montanalinux.org)
704 Church Street
Belgrade, MT 59714
(406)388-0827 [home]
(406)994-3931 [work]