Lucid and OpenVZ and/or LXC ?

[starfry]

Hi there,

I'm well into using OpenVZ on Hardy 8.04. I'm starting to think about the next LTS upgrade that will be Lucid 10.04.

I just downloaded Alpha2 and tried OpenVZ: it isn't there! So I've been searching and it would seem that LXC (Linux Containers) is going to be in Lucid. I'd never heard of LXC before today.

Does anyone know the full story? Will OpenVZ be in Lucid? Even if it is, should one plan on migrating to LXC? What will be the pain involved in that (given the investment in configured and running Hardy based OpenVZ VEs)

As a day 1 plan, I had intended a host upgrade to Lucid leaving the many Hardy based OpenVZ VEs in place and I have (naively) hoped they would just continue working.

Any thoughts/comments appreciated...

[mkvnmtr]

I saw your post and googled LXC. On a short read it looks like this is for apps on the native system. I am still reading.

[narcisgarcia]

I've talked with one Ubuntu-OpenVZ team member, and told me:

• The plan for Lucid as agreed on with Canonical at the UDS is to have LXC in Ubuntu main and use it as a replacement for OpenVZ
• LXC stands for Linux Containers, it's a similar technology but provided by the vanilla kernel instead of an heavily patched kernel like OpenVZ.
• Kernel support is included in mainline since 2.6.26, so it has been a while. Userspace is still in development but works correctly and is integrated with libvirt.
• A OpenVZ container itself should work as-is with LXC, only the configuration will need to be converted.
• LXC doesn't need the VT (vmx) processor instruction set.
• You can assign memory quota for both ram and swap and due memory overcommit without any issue.
• Disk space isn't implemented yet, so you'd have to user regular quotas or use LVM for storage.

Some references to use LXC:

• http://www.stgraber.org/category/lxc
• https://wiki.ubuntu.com/ContainersSpec
• http://www.ibm.com/developerworks/li...xc-containers/

[starfry]

Thanks for the replies. So one question: If I want to continue using OpenVZ on Lucid, will I be able to ?

I'd like the choice, and the ability to migrate over in my own timeframe

I'm running 2.6.24-26 (Hardy) so I don't have the option of migrating in advance.

[narcisgarcia]

With any Ubuntu version (younger or older than 8.04) you can recompile the kernel to use OpenVZ:
http://wiki.openvz.org/Compiling_the...he_Debian_way)

With Ubuntu GNU/Linux 8.04 we had an already compiled+patched kernel for OpenVZ, but you can do the same by yourself.

[bodhi.zazen]

Thanks for the replies. So one question: If I want to continue using OpenVZ on Lucid, will I be able to ?

Almost certainly not.

I use OpenVZ and would advise you migrate to Proxmox.

The problem with OpenVZ is that it is a kernel patch, and there is no patch for more recent kernels.

The "solution" is LXC. I have just started LXC and I will tell you

1. It is not up to par with openvz yet. You will need to be willing to do a lot of reading to migrate.

2. LXC still has bugs. I was unable to boot a Fedora-12 container I built for example.

3. Much of LXC is not there yet, the containers are NOT as isolated as they should be and networking is manual, in order to get networking I had to manually add a bridge (no big deal, but still ... ), manually add an IP to the container, and manually add a route.

4. Documentation for LXC is sketchy at best, it seems scattered and incomplete, for example I can not find a document that explains the config files and options in any detail, most of the stuff I have found seems to use the minimal options.

5. Did I mention LXC containers are not completely isolated from the host ? Isolation seems better in a standard chroot then lxc. One has access to the host file system, I accessed the host swap with no problem, and one can start a process on the host from the container, all without "cracking" anything, simply running an init or upstart script or starting a server in the container can start a process on the host.

6. I have had problems getting the user space tool set working, I need to look into this problem more.

7. Although LXC is reported to work with libvirt, I could find no documentation in my brief search and libvirt seemed to have no clue about LXC.

Now these problems may well be that I do not yet understand LXC, but IMO it is not yet up to par with OpenVZ.

Moving forward, it appears once they work out the bugs and get libvirt up w/ LXC it will almost certainly replace OpenVZ.

On the flip side, LXC are part of the main stream kernel so many more developers are working on LXC and forward compatibility will be much easier.

You can start with LXC very easily, simply

sudo apt-get install lxc

This installs the tools / scripts, lxc is already enabled in the kernel, so installing the lxc package does not affect the host as much.

I suggest playing with lcx in a VM or in a dedicated test host, and it certainly is not ready for deployment in a production environment.

You may wist to look at some of these links:

http://openvz.org/pipermail/devel/20...er/014314.html

http://forum.openvz.org/index.php?t=msg&goto=38118&

http://openvz.org/pipermail/users/20...ry/003189.html

[starfry]

This is a real shame. I've grown to really like OpenVZ. Proxmox isn't really an option for me here because my OpenVZ VE's are running on a desktop workstation box rather than a dedicated server box. OpenVZ has given me what I need and I am mostly happy with it.

I am not afraid of recompiling kernels and I have done this many times. I've never done it on any Ubuntu box however because I wasn't sure how it would affect the ability to run other packaged software that depends on a specific kernel package.

For ease of life I may have to go LXC if the Lucid team don't see sense and include OpenVZ in the next LTS release.

I'm going to take your suggestion and evaluate LXC in a virtual machine.

[Dorowan]

Thanks for the replies. So one question: If I want to continue using OpenVZ on Lucid, will I be able to?

Sinc OpenVZ just released a 2.6.32 Kernel with OpenVZ patches you have a good chance though I do not think the kernel will make it into the official Lucid Lynx release. Maybe you will be able to get it from the OpenVZ repository or from launchpad. At the moment there are only rpms and source.

[narcisgarcia]

As commented by Dorowan OpenVZ released a 2.6.32 Kernel with OpenVZ support. At the moment the only prebuild packages are for rpm-based distros, but server administrators need a reliable way to upgrade our LTS host servers, and LXC sowftare+docummentation is not ready for OpenVZ migration.

[bodhi.zazen]

Sinc OpenVZ just released a 2.6.32 Kernel with OpenVZ patches you have a good chance though I do not think the kernel will make it into the official Lucid Lynx release. Maybe you will be able to get it from the OpenVZ repository or from launchpad. At the moment there are only rpms and source.

If you wish to try that kernel, IMO, I would start with the patch. If that fails you could take a look at converting the .rpm with alien, which is what I believe Proxmox does.

It does not appear either openvz or LXC are priorities for the Ubuntu Developers and if you wish to use OpenVZ I highly suggest Debian, Proxmox, or Centos.