OpenVZ

Back from the LinuxTag

Tue, 30 Jun 2009 21:22:13 GMT

First, hello to all!

Second, my friend Bernhard and I helped Kir with his booth on the LinuxTag. It was a great pleasure for us because Kir is a really cool guy. We had the chance to hear and learn a lot about Kernel development and OpenVZ in general. Also it was very nice to discuss our OpenVZ server farm at work with Kir's Know How. Quote "Kir: Uhh, you perl scripts are really hardcoded" - :o)

I hope we will see us before the next LinuxTag next year. As we spoke about we decide to help the project by doing support on the forum/blog and maybe some wiki stuff (system use case).

For all readers we took some pictures from the booth and us. You can find them on our blog page systec.blogsite.org.

Thank you - It was a lot of fun - Mario

Conferences, conferences...

Mon, 22 Jun 2009 18:10:26 GMT

I am almost ready for the LinuxTag, my flight from Moscow to Berlin is tomorrow mid-day. I have prepared booklets, even in German (thanks to Mario and Bernhard, OpenVZ users from Austria who will also help me with the booth). And I will even have a monitor to demo Overo Gumstix running Linux (thanks to Björn from XtreemFS). So if you are visiting LinuxTag this year, come to say hello!

If you happen to be on a different continent, North America, then I welcome you to visit LinuxSymposium. This is a quite a big annual event, and unlike LinuxWorld (which is now called OpenSourceWorld) they haven't changed their name for 10 years (well, hmm, actually they dropped the Ottawa prefix since this year it will be held in Montreal -- but at least they left the Linux part, the one that is most important for me). For the LinuxSymposium I am preparing a tutorial and a BoF. So, again, come to say hello! :)

LinuxTag: any volunteers?

Wed, 10 Jun 2009 16:24:29 GMT

I have just got my passport back from the German embassy today, with a shiny new Schengen visa and booked tickets to Berlin. Yes, this is for LinuxTag event which will take place in Berlin, Germany, from 24th to 27th of June. OpenVZ will have a booth on the show.

Are there any OpenVZ users living not too far from Berlin* who can help me with the booth (i.e. be a booth star together with me)? Please contact me by leaving a comment here or email to kir at openvz dot org, I need your help.

* from my perspective every German city is not too far from Berlin :) but YMMV.

Completion in vzctl

Fri, 22 May 2009 12:11:43 GMT

There is a nice feature in vzctl (well, technically not in vzctl binary itself; it just comes in vzctl package) that many people don't know about -- completion. This basically makes it able to save a few keystrokes when typing.

Say you want to create a container. You type vzct and press <TAB> -- it completes that to vzctl and a space after. This is usual feature of bash -- it looks all the binaries available in $PATH and tries to complete their names.

Now let's see the vzctl completion:
# vzctl cr<TAB>
completes to
# vzctl create
and then after yet another <TAB> it suggests a CT ID which is the MAX+1 (i.e. if you have containers 101, 102 and 105 it will suggest 106):
# vzctl create 106
Now we want to specify an OS template:
# vzctl create 106 --os<TAB>
will get you to
# vzctl create 106 --ostemplate
and then you press <TAB> again twice to see the list of available OS templates:
# vzctl create 106 --ostemplate <TAB><TAB> centos-5-x86 centos-5-x86-devel fedora-9-x86 suse-11.1-x86
Now you type in the first few characters of the OS template you want to use:
# vzctl create 106 --ostemplate f<TAB>
and it will complete that to
# vzctl create 106 --ostemplate fedora-9-x86
Now, unless you want to specify --config or some other parameters, just press Enter.

This completion is smart -- say, if you want to start a container, type in
# vzctl start <TAB><TAB>
and it will give you the list of container IDs that can be started (i.e. all the stopped containers).

And so on and so forth. Well, you say, it doesn't work! In that case you have to enable it, here's how.

On a RHEL, CentOS or Fedora system run yum install bash-completion and then relogin (i.e. log out and log in again). If your host system is Gentoo, run emerge bash-completion and then eselect bashcomp enable vzctl. I hope someone will comment on how to enable this for Debian/Ubuntu/SUSE or whatever your favorite distro is.

new templates are almost here

Tue, 19 May 2009 14:31:06 GMT

I am preparing an updated set of precreated templates; those should be ready tonight or tomorrow, available from the usual place.

In addition to a bunch of updated templates, this time we add a few new ones:
- Fedora 10 (aka Cambridge)
- openSUSE 11.1
- Ubuntu 9.04 (aka The Jaunty Jackalope)

OpenSUSE is interesting -- apparently they dropped yum (which was available in 10.3 and 11.0 but not in 11.1) and now they have something called zypper. Also note that openSUSE lacks the code name. Apparently the SUSE guys are already aware of the issue and have a plan to fix it -- the next release (openSUSE 11.2) will be codenamed Fichte, after the German XIIX century philosopher. Subsequent openSUSE releases will also be named after famous philosophers -- Rousseau, Voltaire, Lessing (although I'm not sure which Lessing do they have in mind, probably Theodor). Interesting... maybe they got the naming idea from OpenVZ kernels. ;)

Also, during the next update (i.e. in about a month, not now) we are going to remove a few templates that are old and unsupported:
- Debian 3.1 "Sarge" (EOL 30 Mar 2008)
- Fedora 7 (EOL 13 Jul 2008)
- openSUSE 10.3 (EOL 19 Sep 2008)
- Fedora 8 (EOL 7 Jan 2009)
- Ubuntu 7.10 (EOL 18 Apr 2009)
Anybody who's using those distros inside containers should updated to something more (r|d)ecent and supported. You have been warned.

PS For people who use our stable kernels (i.e. RHEL5 branch) -- please note that you have to update to the latest kernel (028stab062.3 at the moment) in order to use Fedora 10 in containers. This is due to a few new system calls recently added to the Linux kernel which Fedora 10 userland expect to have in the kernel. Those syscalls were just backported to our RHEL5 branch by the OpenVZ team.

plone vs. mediawiki

Thu, 02 Apr 2009 08:33:50 GMT

I promised to write more non-OpenVZ specific stuff. Here we go.

About 3 years ago I wrote about my experiences with Plone and Mediawiki. I just reread it this morning because someone left a comment there and it went into my email.

So I briefly visited plone.org to see what are they up to. Insteresting, they fixed some of what I was moaning about in that old post (the part about Joe the user). Apparently Plone 3 has wiki syntax support, versioning and history, and I guess a bunch of other cool features.

I'm not sure if it is any faster now, and whether it's easier to tweak and modify. I hope it is.

But oh no, I don't have enough courage to try it. Although Mediawiki lacks a few features of "the proper CMS" like Plone which I miss, although I prefer Python to PHP, I am still pretty happy using Mediawiki for openvz.org. So I let well enough alone.

Fear no KLOC

Wed, 25 Mar 2009 13:18:52 GMT

From time to time, somebody critisizes OpenVZ kernel patch for its intrusiveness and size. Right, it is big and intrusive -- it adds a whole lot of new features into the kernel. But how big is it?

Our engineer prepared some stats on three different kernels:
1. OpenVZ stable kernel (based on 2.6.18-RHEL5);
2. OpenVZ development kernel (based on 2.6.27);
3. RHEL5.3 kernel (based on 2.6.18).
You can see the results by clicking the image at the right.

Some notes for the graph. For OpenVZ kernels, we distinguish between core kernel changes and the stuff that is built as modules. For RHEL kernel, we break the patchset down into a few categories, such as drivers, Xen, GFS, ext4 and so on; "other" means everything not covered by any other category. The numbers are thousands lines of code added and deleted, combined. A table below the graph has some more details, like how many files were changed, how many lines added and deleted.

Now to the conclusions. Two major points can be made:
1. Even without drivers, RHEL5 kernel patches add/delete 434 KLOCs*, which is 8.5x times bigger then OpenVZ kernel modifications (51 KLOC). So, yes, OpenVZ patch set is big, but not that big.
2. OpenVZ based on mainstream 2.6.27 kernel requires 40% less** modifications to the kernel due to on-going effort to integrate the functionality into mainstream.

* KLOC is a thousand lines of source code.
** we only count the core changes, omitting the modules.

live from SCALE7x

Sun, 22 Feb 2009 14:26:32 GMT

Greetings from SCALE7x! Today will be the second (and the last) day of the show. Yesterday I did a presentation titled "Recent Advances in the Linux Kernel resource management". The scope of the talk is much more technical and narrow than my usual talk about containers. More to say, I was focusing more on mainstream Linux kernel (i.e. cgroups and memory controller) than on OpenVZ kernel (i.e. user beancounters).

I think the talk was well received and I had about 10 different interesting questions, one is puzzling enough so I was not able to provide a good answer. This is definitely a sign of a good audience.

If anyone is interested in slides from my presentation, they are available: OpenOffice ODP (276K), PDF (409K), PPT (437K).

if (time() == 1234567890) celebrate();

Fri, 13 Feb 2009 22:36:13 GMT

Disclaimer:This post is not really related to OpenVZ, but who cares? I don't... :) So from now on I will be writing more here, on just about everything.

In UNIX systems, system time is accounted as a number of seconds since so-called "UNIX epoch" -- 1 January 1970 00:00:00 UTC. This number of seconds is returned by system call time(), plus there are library routines to convert it to more human-appealing formats.

You can guess the number is pretty big nowdays, incrementing every second. In fact, it's already over a million seconds, and in about 1 hour it will be equal to 1234567890. For some people this is a good enough reason to have a beer or two in a good company. Check http://www.1234567890day.com/ for 1234567890 parties around the globe. As for myself, I will just watch the number growing. Some kind of a meditation, similar to staring at an open fire, or flowing water, or people at work... I can do that for hours! Just kidding...

On Linux, you can see the current time() using date +%s command. Enjoy.

Getting ready for SCALE7x

Thu, 12 Feb 2009 15:57:57 GMT

In about a week I will be in Los Angeles for the annual Southern California Linux Expo, a.k.a. SCALE. It is quite a big event. Well, not quite as big as LinuxWorld or Linux Symposium, but still big enough and growing bigger each year. I'd like to say this conference is of good spirit, whatever that means.

Like the last year, we were granted a booth in the dot-org area (#63), plus I will be giving a talk titled "Recent advances in the Linux resource management", talking about cgroups, memory controller and stuff. Because of the booth I am not coming along -- Lesya Novaselskaya will hostess the booth. Lesya is working for Parallels as a Quality Assurance engineer, her job is to test various software including OpenVZ in order to make it bullet-proof and rock solid.

We still have lots of things to do to be fully prepared for the event. I have already created a brand new OpenVZ t-shirt design codenamed "kernel classics" which you can see on the right (also, here is the back design in hi-res). It plays around the fact that we name our 2.6.26- and 2.6.27-based kernels after famous Russian writers and painters, respectively. If you will be at the conference and tell us your OpenVZ story, you get your t-shirt. If you are not going to visit SCALE but eager to get such a t-shirt (not the same since I'm ordering from a different place, but with the very same graphics) you can buy it from cafepress (previous "container lifecycle" t-shirt is also available).

I hope I will also prepare the new DVD images containing a live CD OpenVZ distro which could be used to get a feeling of what OpenVZ is without installing it, plus all the latest kernels, tools and templates.

'dab' Debian/Ubuntu Appliance Builder released!

Tue, 20 Jan 2009 10:33:20 GMT

We just published our Debian/Ubuntu appliance builder for OpenVZ (of course perfectly usable on Proxmox VE).

Short description

Creating high quality appliances is a difficult task and requires deep knowledge of the underlying operating system. So we created the 'Debian Appliance Builder' to simplify that task. 'dab' is a script to automate the creation of OpenVZ appliances. It is basically a rewrite of debootstrap in perl, but uses OpenVZ instead of chroot and generates OpenVZ templates. Another difference is that it supports multi-stage building of templates. That way you can execute arbitrary scripts between package installation steps to accomplish what you want.

Furthermore, some common tasks are fully automated - like setting up a database server (mysql or postgres). To accomplish minimal template creation time, packages are cached to a local directory, so you do not need a local Debian/Ubuntu mirror (although this would speed up the first run). All generated templates includes an appliance description file. Those can be used to build appliance repositories.

Virtual appliances are a well known and quite successful way to demonstrate and run server software. But till now, no high quality appliance builder for OpenVZ was available.

Anybody is talking about the economic and financial crisis – a good chance to bring powerful open source software to the enterprise customer – start now using OpenVZ for virtual appliances!

All details:
http://pve.proxmox.com/wiki/Debian_Appliance_Builder

Best Regards,

Martin Maurer

martin@proxmox.com
http://www.proxmox.com
____________________________________________________________________
Proxmox Server Solutions GmbH
Kohlgasse 51/10, 1050 Vienna, Austria

2.6.27 kernel and Russian painters

Mon, 19 Jan 2009 15:18:52 GMT

A new 2.6.27-based OpenVZ branch is opened, and the first 2.6.27-based OpenVZ is released.

The idea of using names instead of numbers for kernel releases is working for 2.6.26, and we decided to have some fun with 2.6.27 kernels, too. These kernels are [to be] named after famous Russian painters, of course in the alphabetical order.

First 2.6.27 OpenVZ kernel is named after Ivan Konstantinovich Aivazovsky. Aivazovsky is a great painter and I'd love to add a link to some of his masterpieces here, but while trying to find a good reproduction of "The Ninth Wave" I realized that a typical notebook/PC is incapable of displaying such art. Then you try to fit a 2x3 meters painting into a 22" computer screen, nothing good is to be expected. Even in case of high resolution copy stored in a lossless format you either see a full picture but details are lost, or you see some part of it with all the details but then you don't see the full picture. So be aware that a painting that you see online is a pathetic shadow of what you can enjoy in a real (i.e. offline) museum or art gallery.

The 2.6.27-aivazovsky kernel, on the other side, is perfect for you PC, so enjoy.

New year, new stuff

Fri, 09 Jan 2009 17:17:17 GMT

Consider this as a new year gifts from Father Frost, or Dad Moroz, or Santa Clous, or me, if you so prefer.

First gift is a new fresh set of precreated templates, which spent quite some time in beta before. Those are the same templates, but updated couple of days ago, plus there is Ubuntu-8.10 added. I hope I will update those monthly or so, since now I have some automation in place. A 'date' column was added to list of template files on wiki so you can easily see how old are those.

Second one is new shiny SSL certificates for https://wiki.openvz.org/ and https://bugzilla.openvz.org/. I call it shiny because they are neither self-signed nor bough from a commercial certificate authority. As you can see they are CAcert.org certificates. CAcert is an organisation which is building so-called web of trust, and acts as a certificate authority for its members. If you need free certificates, you are welcome to join. And, if you decide to trust CAcert as a certificate authority and your browser isn't configured for it yet, you have to import their root certificate.

Finally, a new 2.6.24 kernel is coming out later today. Others will follow. Update: here it is, 2.6.24-ovz007.1.

The Linux Link Tech Show

Wed, 17 Dec 2008 19:19:50 GMT

I will be a guest on The Linux Link Tech Show this evening (Wednesday, Dec. 17th) representing the OpenVZ Project so check it out. It will be streamed live starting at 8:30PM Eastern Standard Time and here are links for your favorite audio application that can stream over http:

At some point after the live show, it will be archived and available for download as an .mp3 or .ogg.

Updated Introduction to OpenVZ screencast

Tue, 09 Dec 2008 23:39:52 GMT

Since the last intro video I made was over 1.5 years ago, I thought I'd make a new one.

Screencast: vzpkg2 & pkg-cacher

Wed, 19 Nov 2008 20:52:50 GMT

Robert Nelson released updated versions of vzpkg2 and pkg-cacher... as well as updated OS Template metadata packages for Fedora, CentOS, Debian and Ubuntu. In all there are 48 different OS Templates that can easily be built using his software. I'm hoping to get more people in the community interested/involved so I made a screencast. If more people get involved, do more testing, and provide feedback... hopefully at some point in the not too distant future Robert's new software can replace the stock vzpkg that the OpenVZ Project provides.

New vzctl and vzquota

Tue, 11 Nov 2008 17:52:07 GMT

Today is definitely a day of releases.

OpenVZ project has released both new vzctl and vzquota tools today.

New vzctl has a handful of new small features and a bunch of bugfixes, including compatibility with recent glibc, bash, and kernel headers.

New vzquota has only one (but quite useful) new feature -- an ability to explain what's wrong when it can not turn container's disk quota on or off. Recent OpenVZ kernels have a feature to report open files in container's private area, and now with the new vzquota the feature is finally available for mere mortals.

In the meantime Parallels has released Parallels Desktop for Mac 4.0 -- and that's just a coincidence, I'm sure they do not sync their release cycles with OpenVZ. Or maybe it's not a coincidence... We're sitting in the same office and for the last few weeks they've been providing free late dinners because of their release, that maybe made me leave the office later and thus maybe gave more time to work on OpenVZ tools. :)

OpenVZ is running on an ARM (Gumstix Overo)!

Thu, 23 Oct 2008 16:08:07 GMT

When my colleague Pavel Emelyanov returned from the 2008 Linux kernel summit back in September he brought a small present for me -- a Gumstix Overo (every LKS participant got one for free; yet another reason to become a high-profile kernel developer!). Overo is a computer (well, actually a set of boards and cables) with a CPU board the size of a gum stick, featuring TI OMAP3 CPU, 128 megs of RAM and a microSD slot. It also has 802.11g Wi-Fi and Bluetooth but those happens to be completely dead as this the first beta release of hardware.

For the last few days I was digging into a project to make OpenVZ running on this Overo thing. That involved patching OpenVZ kernel to support ARM architecture, building vzctl package (.ipk) for ARM using bitbake, and creating a template.

It was amazingly easy to port the OpenVZ kernel to ARM; you can see here that besides a big-all-in-one-openvz-for-2.6.27 patch I only had to add 4 tiny ARM-specific patches (1, 2, 3, 4). For vzctl, it was even easier -- all I had to do is to add openvz syscall numbers for ARM which were added, and create a bitbake recipe file.

Creating a template for ARM architecture was tougher but I managed to win that fight, too -- you can find a Debian Lenny template here.

Here is an except from a terminal session showing OpenVZ on Overo:


root@overo:~# uname -a
Linux overo 2.6.27-omap1 #1 Tue Oct 21 21:19:40 MSD 2008 armv7l unknown unknown GNU/Linux

root@overo:~# cat /proc/vz/version
037test001

root@overo:~# vzlist
      CTID      NPROC STATUS  IP_ADDR         HOSTNAME
       777          5 running -               -

root@overo:~# vzctl enter 777
entered into CT 777
-bash-3.2# ps axf
Unknown HZ value! (0) Assume 100.
  PID TTY      STAT   TIME COMMAND
  310 ?        Ss     0:00 vzctl: pts/0   
  311 pts/0    Ss     0:00  \_ -bash
  313 pts/0    R+     0:00      \_ ps axf
    1 ?        Ss     0:00 init [2]      
  208 ?        Sl     0:00 /usr/sbin/rsyslogd -c3
  227 ?        Ss     0:00 /usr/sbin/cron

Please note that all this is still in very alpha stage -- there are errors, bugs, ugly warnings, you have to modify some things in place etc. But it's working. If someone is interested in running OpenVZ on ARM hardware, please let me know -- leave a comment here or email kir (A) openvz (.) org.

2.6.26 kernel and Russian writers

Thu, 02 Oct 2008 15:04:57 GMT

We are going to release first 2.6.26-based kernel soon -- it went to testing today and hopefully will be released next week.

We are also changing the versioning scheme -- instead of boring numbers like 001, 002, 003 etc., every 2.6.26 OpenVZ kernel will be named after one or another great Russian writer. We will do it in alphabetical order so there will be no upgrade pain.

As you can see here, first 2.6.26 is named after Mikhail Afanasievich Bulgakov. I personally enjoy his The Master and Margarita (it's truly a masterpiece; although I'm afraid a lot is lost in translation) and Heart of a Dog.

And yes, we are doing that just for fun.

Interview with vzpkg2 and pkg-cacher creator Robert Nelson

Sat, 27 Sep 2008 23:32:17 GMT

Robert Nelson was kind enough to agree to an email-based interview which readers of the OpenVZ Users mailing list will have already seen. Robert has written a replacement for vzpkg (currently named vzpkg2) and has greatly enhanced it with the addition of a package named pkg-cacher. For an introduction to OS Templates and the tools used to manage them as well as Robert's fantastic answers, see:

Interview with vzpkg2 and pkg-cacher creator Robert Nelson

Obligatory quote:

ML: You have added a number of features / capabilities to vzpkg. Could you give us an overview of what's new?

Robert: I think the most significant change over the stock version of vzpkg is the separation of the packager specific code from the higher level code. This allows scripts to be written to support other package managers like apt which is used on Debian and Ubuntu.

The other slightly less significant change is the introduction of the concept of a hierarchical structure to the template meta data. Information which is the same for all versions and platforms of a distribution need only be specified once. If there is a need for separate settings for a specific version it can be overridden by a file lower in the template meta data tree.

Also new packager-independent commands have been added for managing packages in installed containers.

One thing worth mentioning is that while the number of OS Template Metadata packages provided by the OpenVZ Project is quite limited, Robert has created new metadata packages for vzpkg2 that allow for easily building CentOS, Debian, Fedora, and Ubuntu OS Templates. If I counted correctly, Robert's new metadata packages make it easy to build 44 different OS Templates. Wow!

It might take a few more weeks before vzpkg2 and pkg-cacher are finalized and added to the OpenVZ Project repositories. If you don't want to wait and would like to help out with testing, Robert has posted some instructions to the OpenVZ Users mailing list and here is a link to the archive for the time period in question:

http://openvz.org/pipermail/users/2008-September/thread.html

Net "beta" OS Templates

Wed, 27 Aug 2008 16:31:35 GMT

Just wanted to mention that Kir created a new directory at the top level of the download site named beta. Inside of it you'll find a directory structure that you can eventually drill down into to find a number of new, beta OS Templates that Kir has built. Here's a list:

centos-4-x86_64.tar.gz, centos-4-x86.tar.gz, centos-5-x86_64.tar.gz, centos-5-x86.tar.gz, debian-3.1-x86.tar.gz, debian-4.0-x86_64.tar.gz, debian-4.0-x86.tar.gz, fedora-7-x86_64.tar.gz, fedora-7-x86.tar.gz, fedora-8-x86_64.tar.gz, fedora-8-x86.tar.gz, fedora-9-x86_64.tar.gz, fedora-9-x86.tar.gz, suse-10.3-x86_64.tar.gz, suse-10.3-x86.tar.gz, ubuntu-7.10-x86_64.tar.gz, ubuntu-7.10-x86.tar.gz, ubuntu-8.04-x86_64.tar.gz, ubuntu-8.04-x86.tar.gz

Sorry SUSE fans, no openSUSE 11 yet. :(

One big difference is that the Fedora and CentOS OS Templates now include yum which will make a number of people happy. No more fumbling around trying to download a bunch of rpm packages an using rpm to install yum.

The CentOS 5 OS Template

Oddly enough an OpenVZ "official" pre-created OS Template for CentOS 5 did not previously exist although there have been a number of builds posted in the "contrib" section. So far, I've tested out the CentOS 5 x86 and x86_64 OS Templates and they are a bit different from the contrib releases. For one thing, udevd is installed and running and the vzdev package puts files in /etc/udev/devices/ rather than /dev. This is good, because on previous CentOS Templates udev was not installed and if it happened to get installed as a dependency for something else, it would prevent future container starts from working... until udev was removed or the starting of udev was commented out from /etc/rc.d/rc.sysinit. Perhaps including udev will make migrating physical servers to OpenVZ containers a little more easy.

There are a number of updated vz packages installed that include:

vzdummy-kernel-el5, vzdummy-jre-fc6, vzdummy-glibc, vzdummy-apache, vzdev

The CentOS 5 OS Template is quite light-weight resource wise as a container made from initially only takes up about 14MB of RAM. The vzdummy-apache package helps there because it offers a modification to the stock Apache configuration (/etc/httpd/conf.d/swtune.conf) that changes the StartServers value to 1.

Community, please test these out and report any bugs you find!

how free software works: Red Hat and OpenVZ

Wed, 20 Aug 2008 14:24:18 GMT

Here is an example of how things are working in the free software world.

We at OpenVZ use kernels from Red Hat Enterprise Linux as a base for our OpenVZ kernels. This is because vendors such as Red Hat invest a lot of work into making their kernels really stable. The usual recipe for a super-stable kernel is to pick a mainstream kernel and marinate it in QA for at least half a year (more for the best results), doing bugfixing and cherry-picking of fixes and driver updates from the mainstream. This way one have enough time to test it, plus (at least in theory) one get new fixes but do not get new bugs slipped into one's kernel. This is what Red Hat (and other guys such as Novell/SUSE) does for their kernels, and believe me it's quite a lot of work to do, and the end result is of great value.

Here comes the beauty of free software: now everybody can use the result of Red Hat's work. Yes, this is exactly what we do. At this point you might stand up saying: all right, Red Hat invested a lot of resources into something you use for free, this does not look like a fair deal.

Fortunately I have a good answer. Here is the list of bug (i.e. software defect) reports that were fixed in Red Hat Enterprise Linux kernels thanks to OpenVZ team (in some way): #405521, #247379, #205335 , #210852, #168659, #243252, #207463, #228461, #243263, #224541, #232209, #232211, #239767, #220971, #400651, #214778, #203894, #212144, #215715, #241096, #241096, #439670. These 22 bugs are all kernel bugs, most are security-related (and therefore quite serious). Almost all the bug reports from the list include patches (i.e. changes to code to fix a problem reported), so those are not like "hey, you have a problem", but rather "you have a problem and here's the solution".

The majority of those bugs were found while testing OpenVZ kernels. This is what we contribute back. This is also a lot of work and of great value -- some of those bugs were really hard to find and/or fix.

The latest (23rd) addition to the above list is bug #454865, which is actually a regression in a new version of RHEL4 kernel. Again, this report not only includes a clear description of what's wrong, but also a test case program which reproduces the bug, and a patch to fix it. Clear test cases are very important because those can be included into a validation test suite, to make sure bugs are not popping out for the second time (which sometimes happens in the real world).

This is just one example, a close-up picture. The big picture is free software developers and users helping other developers and users. Unus pro omnibus, omnes pro uno.

Is anyone aware of a distro which supports its running in OpenVZ?

Sat, 16 Aug 2008 00:47:16 GMT

I mean, in case you're doing a physical to VE migration, you're to remember turning some things off and doing other tuning («rat-file works»). And it's easy to miss something. At the other hand, the distro-devs know their rc-system perfectly (at least some of them should) and direct support of distro run inside VE would be really great. But I'm afraid there're no such distros, am I wrong?

Live from LinuxWorld expo

Tue, 05 Aug 2008 21:33:35 GMT

I am currently standing at the OpenVZ booth at LinuxWorld Conference and Expo, San Francisco. Today is the first day of the show, the traffic is pretty good. The only bad thing is Delta lost my bag with booth banners and rollups so the booth looks a bit empty.

Marc Perkel, Scott Dowdle and Adeel Nazir are all manning the booth, talking to existing and (I hope) future OpenVZ users. So I was able to release a new RHEL5-based kernel right from here.

Tomorrow morning at 10:15 I will be giving a talk titled "Containers, Virtualization, and Live Migration".

Containers mini-summit and Linux Symposium

Tue, 22 Jul 2008 15:50:12 GMT

While I am writing this, people are discussing the future of containers in the Linux Kernel at the containers mini-summit which is happening in Ottawa at the moment. You can check some rough notes from the event here. Three guys from OpenVZ team are there: Pavel Emelyanov, Denis Lunev, and Andrey Mirkin.

If you are attending Linux Symposium in Ottawa, note that this Friday, 25th, Andrey Mirkin will talk about containers checkpointing and live migration (12:00, Rockhopper room). It's going to be an interesting talk, do not miss it.

Also, this Wednesday, 23rd, Balbir Singh will lead a BoF on Memory Controller (17:45, Fiordland room). Memory controller is quite important for containers, and while some stuff are already in the mainline kernel, there's still lots to be discussed and developed in the area. You can think of this BoF as an extension to containers mini-summit.