OpenVZ

Parallels ranked among top updaters for 2.6.32

Sat, 28 Aug 2010 13:59:48 GMT

Jon Corbet wrote a piece yesterday that will be in next week's Linux Weekly News entitled, "Some numbers and thoughts on the stable kernels". The point of the article is to review the last five years of stable mainline kernel releases and the updates to them.

As you may know, Parallels / OpenVZ has a 2.6.32 "devel" branch and a goal of making it the next "stable" branch. They have had several 2.6.32 releases and have been putting a lot of work into it. This work has also lead to 29 patches so far that have made their way into the mainline 2.6.32 kernel updates. This ranks Parallels the 9th top updates contributor (or 11th if you count "None" and "Unknown"). It should be noted that these mainline contributions benefit everyone and are not OpenVZ specific... just in case someone were to get confused and wrongly think the patches were an attempt to get OpenVZ into the mainline.

Want to read about it for yourself? It is currently subscriber-only content that should becoming freely available on September 9th. I've been an LWN reader since the beginning and a paying subscriber since they went to a subscription model. I can provide a "subscriber-link" that will allow non-subscribers to read the article as an enticement to become a subscriber. Once it is freely released, I'll try and remember to update this post with a new link.

To the Parallels / OpenVZ developers I say... Thanks for the continuing hard work on 2.6.32, your contributions are appreciated... and I look forward to the upcoming "stable" 2.6.32 OpenVZ kernel.

OpenVZ Presentation for GOLUM

Wed, 18 Aug 2010 17:09:45 GMT

I'm on vacation in Memphis, Tennessee visiting family. A couple of weeks before going on vacation I looked for a Linux Users Group in Memphis to see if I could attend or even possibly present at one of their meetings. The Group of Linux Users Memphis (GOLUM) has been around for well over a decade and continues to have an active mailing list... but their website was outdated and they hadn't had a meeting in the last two years. My inquiry lead to a resurgence of GOLUM with a desire to start having monthly meetings again.

They had to locate a venue for the meetings, set a date and time, etc... and I will be presenting "Introduction to OpenVZ" for their first new meeting. For details see their website... which has only recently been redone and is still in the beginnings stage.

Before the topic was picked I gave them 5 or 6 potential topics to pick from and they voted and selected OpenVZ. Seems that OpenVZ is not well known in Memphis but I hope to change that.

hello from Ottawa

Tue, 13 Jul 2010 23:10:27 GMT

When I have a high temperature, i.e. fever, I am very talkative. I just measured it up to 39.6deg;C (103.3°F). Now I don't have anyone to talk to verbally, so I'm blogging. You have been warned. But no, this post is not contageous.

I am in Ottawa since last night, despite all the challanges on the way -- our flight from Moscow was delayed by about half an hour, and in Washington there was a huge queue to the passport officers. And it was a queue for transfer passengers, who obviously have a connecting flight in a few. Airport personnel was of no help, they basically say that everyone is in the same situation. Well, I guess, it might have made sense to check the next flight take-off time of complaining passengers and move some of them to "US citizens" queue which was 6x smaller. They did that, but in random manner, i.e. for some passengers who already made it to the first row. I guess a CFQ scheduler would be a nice addition to that system.

Anyway, after more than 1 hour in a queue I reached the office and was allowed to enter the USA. This was only needed for immediately taking the plane to Canada (where there is another border and another officer and I have another visa in my passport). It is a bit strange to me that there is no direct way for transfer passengers going to other countries. When I said "thank you, sir, bye" to the USA officer, it was exactly 5:20pm -- the take-off time of my flight.

So I ran to the baggage check out, then to the security control, then to the gate (a helpful lady said the plane is still there). It took me 10 minutes to go from the officer to the gate, including the time to go back to pick one bag which I forgot at security check. OK, I am sweating and breating hard, but I am in the place.

The big problem is I caught a cold during the first flight, and now I feel strange. I can not listen to the talks (except for the keynote), I am taking pills (how paracetamol is named acetaminophen here, and all the other drugs are either absent, not OTC, or have different names is yet another story I won't tell here to save Internet bandwidth and LJ.com storage) and such, gargling the NaCl solution, and all that. So far it helps a little -- I either have a fever or feel like a slowpoke under the drugs.

My talk is moved from Wednesday evening to Thursday morning (not because of me, and I only found it while getting a badge). I hope I will be less of a hot vegetable by that time. I need to make it because I already did most of it.

Just in case you missed it

Thu, 01 Jul 2010 21:29:38 GMT

Just wanted to mention a few news items from the OpenVZ Project.

Updated vzctl - vzctl 3.0.24 has been released. Even though the version number only changed from 3.0.23 to 3.0.24 there are a ton of changes, fixes and some feature additions. Of special interest is the --swappages option as well as being able to refer to a container by its name rather than requiring the CTID with vzmigrate. Overall it was a long overdue, much appreciated update.

Updated Official OS Templates - The last wiki notice is dated April 27th but looking today at the dates on the OS Templates they appear to have been updated May 27th. One thing to note is that there are now OS Templates for Ubuntu 10.04 which I'm sure Ubuntu folks will be happy about.

Beta Fedora 13 OS Templates - And speaking of OS Templates, Kir just released Beta OS Templates for Fedora 13. The day Fedora 13 was released I tried creating my own OS Templates by taking Fedora 12 containers and upgrading them but ran into a snag. With Fedora 13 a lot of new stuff has been added to the init setup and some of it causes a container to just hang during init. I was glad to see the beta OS Templates released. I created containers from them, made my own changes, and then uploaded those to the contrib section.

As luck would have it, later in the afternoon the Fedora Project release a whole bunch of updates and among them was a new initscripts package. I suspected that when I upgraded my container whatever changes the OpenVZ folks had made to the init setup that made it work in a container would be wiped out and I was correct as upgrading the initscripts package did indeed make the container get stuck in the init process upon container reboot. I ended up filing two bugs: 1566 and 1567 and await their joyful resolution.

*** Please note*** Any URLs mentioned (and the information they contain) in this posting are time sensitive and will surely be outdated not long after posting.

openvz for Debian Squeeze

Sat, 12 Jun 2010 12:17:55 GMT

I am still at the OpenVZ booth at LinuxTag 2010 in Berlin. At least two people asked me about the status of OpenVZ kernel for the upcoming Debian Squeeze. Specifically, they said, there is no openvz kernel in "testing" repository (i.e. what will become Squeeze when it will be released). My guess is some more people interesting in that, so here's the public answer.

We are working pretty close with the Debian kernel team, you can see some traces of that on either debian-kernel AT lists.debian.org or debian AT openvz.org mailing lists. Specifically, we work together to bring good quality OpenVZ kernel to Squeeze, and this was one of the main reasons for us to port to 2.6.32.

But yesterday we tried to search for openvz linux-image on packages.debian.org and it gave us no results for testing. I then emailed Max Attems (who maintains our kernels in Debian) and this is his response:

it should be there now, the switch to libata did uphold testing
transition of linux-2.6 for quite some time, so testing had an
outdated linux-2.6 for quite some while

Indeed, the kernel is now there. So yes, Squeeze will have OpenVZ kernel, and I guess it can also be used by people who switched to Ubuntu 10.4.

running firefox in a container

Wed, 09 Jun 2010 15:24:41 GMT

I am standing here at the LinuxTag 2010 event, so if you are in Berlin this week come to our booth to say hello (and maybe recommend a local beer place to go).

One visitor asked me if it's possible to run Firefox inside a container (with the main purpose to browse insecure sites). Yes, it is possible, there are two ways -- using Xvnc and SSH's X forwarding. I just implemented it here (using the latter way), and want to share the experience, because there are a few rough edges here and there.

We start with the "vanilla" Fedora 12 template:

vzctl create 777 --ostemplate fedora-12-x86
vzctl start 777

Next thing to do is to make the container access the network. It can be done in different ways, here I used the NAT technique described in wiki, so I am skipping this part here. Just do not forget to set up the nameserver entry in container's /etc/resolv.conf.

At this point you already have an Internet available in container, let's check it:
vzctl exec 777 ping -c 1 openvz.org

OK, now it's time to install firefox and other needed stuff. Besides firefox itself and its dependcies, you need xauth (for ssh forwarding to work) and some fonts that firefox will use:
vzctl exec 777 yum install firefox xauth liberation\*fonts
This command will result in downloading and installing about 100 packages or so, thus it's a perfect time to enjoy some tea.

Next thing to do is to enable X forwarding inside the container:

vzctl exec 777 sed 's/^.*X11Forwarding .*$/X11Forwarding yes/'
vzctl exec 777 /etc/init.d/sshd restart

Now, set up a user account in CT to run firefox:
vzctl set 777 --userpasswd ffox:mysecpass

All right, time to actually run firefox. But first make sure you do not have it runnng locally, because if you do, remote firefox will just open up a new window of your already running firefox instance. So,

killall -TERM firefox
ssh -Y x.x.x.x dbus-launch firefox

Oh yes, we need dbus-launch here because otherwise firefox complains that it is not able to find machine uuid or something -- apparently nowdays Firefox can't be happy without dbus.

That's pretty much it. Enjoy.

Less branches, more kernels

Mon, 26 Apr 2010 12:47:47 GMT

We have just announced that we stop making new releases for OpenVZ kernel branches 2.6.24, 2.6.26, and 2.6.18. So, from now on we only have 2.6.27, 2.6.32, RHEL4-2.6.9 and RHEL5-2.6.18. Removing the number of parallel kernel branches we have to maintain really helps to concentrate on supporting the remaining ones and moving to mainline. I hope that doesn't affect anyone too much -- from where I stand most users run either stable (i.e. RHEL5-2.6.18) or bleeding edge (2.6.32, before it used to be 2.6.27). In any case, we are not dropping support for vendor kernels, such as OpenVZ kernels in Debian and Ubuntu -- those are still supported from us for the lifetime of the distributions that carry it, we will help with OpenVZ bugs in those kernels through the usual channel.

On the remaining branches. Last Thursday we did an update to 2.6.32 kernel fixing some nasty bugs found in the first public version, and today we updated 2.6.27 kernel as well. Speaking of 2.6.27, it will eventually be dropped as well, but we will keep maintaining it for at least a few more months.

Stable kernel update (RHEL5.5 based, 028stab069...) is currently in testing, but don't expect it to be released real soon now -- previous experience tells us that .y updates are not that easy. We also anticipate to open RHEL6-2.6.32 branch soon, since Red Hat already shooted a beta of their upcoming release.

OpenVZ vs KVM, or Car vs Bike

Wed, 07 Apr 2010 19:39:00 GMT

Today I came across the page which compares OpenVZ to KVM to Xen. Leaving Xen aside, from that one it looks like KVM is ways better, it got all the green pluses, while OpenVZ got all the dull minuses, except for a few features where it says "limited support".

For example, from the author's POV, KVM supports cool features such as "Independent kernel" and "Independent kernel modules" , while OpenVZ lacks all that. I am not mentioning "Full control on sockets and processes" -- definitely, such things as sockets and processes are completely out of control when you use OpenVZ, to the extent that you can not distinguish between a process, a socket, and a potato! (Was that sarcasm? Yes, in fact I don't have an idea of what do they mean by that statement...)

But such a comparison is inspiring, so I invested 15 minutes of my time and made my own, titled Car vs bike. It clearly states that a car is better than a bike -- its capacity is higher and it doesn't require lots of muscle power. After all, it has powered steering wheel (not mentioning powered windows) and can come with an automatic gearbox, air conditioning and even a sunroof! A bike, from the other side, is missing a lot of features -- even windshield wipers are absent which are standard for every car since about 1925!

Actually, I didn't stop there and made yet another comparison, titled Bike vs car. Now it's perfectly clear that a bike is a better choice than a car, since it's cheaper, ecologically clean, and you can even take it with you on a train! A car is big and heavy, it requires periodical refuelling and a parking spot.

Both comparisons are on the openvz wiki, so feel free to edit and add more features!

2.6.32 is here

Wed, 24 Mar 2010 13:43:01 GMT

Recently we have opened a git repository for 2.6.32 based OpenVZ kernel. The port to 2.6.32 kernel was primarily targeted for the next Debian "Squeeze" release which is due in a few months. The kernel is already there, kudos to Max Attempts

That doesn't mean we forgot users of RPM-based distros. Yesterday we have uploaded the first 2.6.32 release, named after the Soviet/Russian cosmonaut Viktor Afanasyev. Yes, the kernels from 2.6.32 branch will be named after cosmonauts.

Please update your openvz.repo, enable the 2.6.32 kernel repo, install this kernel and play with it (not on your production machines though).

SCALE8x, OpenVZ goodies, and new kernels (including 2.6.32)

Tue, 16 Feb 2010 15:56:46 GMT

I am flying from Moscow to Los Angeles tomorrow. It's 13 hours in the air but right to the place I need (and want) to be -- SCALE8x. Just before SCALE, though, I will be in San Francisco for a day and a half -- let me know if you want to meet for a glass of beer or shot of coffee. No vodka, I only drink it when it's cold. Right, Moscow is very cold in the winter...

My plans about new t-shirts for SCALE are not fulfilled; instead I want to print some stickers/labels and maybe something like postcards. I am still designing those, hope to print overnight at Fedex Office when I arrive. An OpenVZ sticker is what I always wanted personally -- my notebook cover carries a lot of stickers (mostly related to GNU and Linux), but OpenVZ one is missing. So I am kinda using my official position to get what I want :) -- if I am not mistaken the correct English word is jobbery.

In the meantime, and this is now fully official, OpenVZ kernel team is working on porting our stuff to Linux kernel 2.6.32. This will take about a month, and we hope to have it working in time to include into next Debian release.

While 2.6.32 is some time away, we keep updating our stable (RHEL5-based) kernel. You can have a sneak preview of newest kernel changelog here. One feature worth noticing is added support for signalfd() syscall which is desperately needed by late versions of udevd and thus all the latest distros (like Fedora 12 and Ubuntu 9.10) which you might want to run in a container.

new openvz t-shirt

Wed, 20 Jan 2010 16:59:07 GMT

OpenVZ will have a booth at the upcoming SCALE8x conference in Los Angeles, California, USA.

I want to design a new t-shirt for the conference (and other future events). So far we have two designs (about which I wrote before here): first "container lifecycle" and then "kernel classics" (you can see both at the shop). Now I want to have something as geeky as the first design, which looks like a screenshot from a terminal, but using a dark-colored t-shirt (I think dark green will fit well).

If you have any suggestions for the design, or yet better can draw it (or a mock-up) -- please speak up here or email me (kir at openvz org). If OpenVZ will take your design I promise to post two t-shirts to you.

An OpenVZ Experiment, 1 year later

Thu, 10 Dec 2009 12:35:35 GMT

Some of you may recall that last December I did an experiment where I created 638 OpenVZ containers on an HP Proliant DL380 G5 machine with dual quad-core CPUs and 32GB of RAM. I stopped there because I ran into an error. Well, one of the OpenVZ / Parallels developers suggested a fix back in July both as a comment to my article and as a comment to the bug report... but somehow I overlooked it until I ran across it again the other day when cleaning out my email.

I finally got a chance to give it a try and sure enough it removed the limit I had run into (the sysctl kernel.pid_max default setting being too low) and I verified it by creating 700 containers.

At first I decided to stop there but then I got an email from Kir asking if disk space was going to end up being my real limitation. I'm wondering if Kir has seen other experiments that go to this extreme or if he is simply a good guesser (with some inside information)? Anyway, I decide to bump it up to 1,000 containers. Sure enough, the machine is handling it just fine.

I didn't do a completely new write up, I just wrote a few more comments to the original article and you can find it here:

An OpenVZ Experiment - How many containers?
http://www.montanalinux.org/openvz-experiment.html

vzctl-3.0.24 is on its way; some thoughts on code refactoring

Tue, 17 Nov 2009 20:50:43 GMT

Long time no see. It's 11pm here now and I'm still in the office. Just though about why not to post to the blog right before I drive home. Really, why not?

I'm mostly working on new vzctl release lately (you can see the progress in vzctl's git web interface here). The ultimate task is to fix most of bugs opened for vzctl in OpenVZ bugzilla (some are dated back to 2007 -- no, they are not critical or even major, but anyway). So far the list of vzctl bugs yet opened are down to one singe page (i.e. scroll bar has disappeared from the browser window) which is a big improvement.

The process is somewhat slow because of my attitute to fix even minor things thenever I notice them -- known as code refactoring. The simplest example is when you open a C file in vim (or Emacs, whatever) and see that there are spaces instead of tabs. When you notice it, there are three ways to go: (A) leave it as is; (B) fix it in place, keep working on what you've planned, commit; (C) fix it, make a separate commit, then continue working on what you've planned.

Way A is not that bad, actually, it's definitely better than B, because the result of B is a spaghetti of a functional (e.g. a new feature or a bugfix) and non-functional (e.g. whitespace cleanup) changes. Mixing apples and oranges is a bad thing to do: it makes patch review harder, it makes porting between branches harder, and in case you'll want to revert the patch (say because of a bug in new code) you will also revert those cleanups (which are not buggy). So, if you are not a perfectionist, better follow way A but please not B.

Unfortunately I just can't ignore the bad things I see, so I follow the way C. Sometimes this is very annoying, because instead of implementing a new feature you keep refactoring your code for hours, sometimes even days. No, it's not only whitespace cleanups or fixing typos in comments. Sometimes you see that there are a few identical snippets of code and you put that code into a new function. Sometimes you notice that some function arguments are unused (or always the same) and you remove those. Sometimes you just read the code and see there is a bug in it, and you fix it. Oh, the text of error message is not clear enough -- you fix it. The typesetting of a man page is wrong (e.g. bold is used instead of italic for variable argument) -- you fix it. You see that a function is not used outside of the source file -- you make it static and remove its prototype from a header file. You notice a typo in the function name (and of course also in every place that calls it, since otherwise that code won't compile) -- you fix it. A typo in a comment -- fix it! And so on, and so forth...

Every single thing from the above paragraph (and some more) happened to me when I was working on the boot order priority feature (the subject of OpenVZ bug #1300). So I ended up with 22 (twenty two) code commits, from which 3 implement the actual feature, 1 documents it, and the other 18 are all code refactoring, preparation and minor bugfixing.

The way to perfection is never easy. That doesn't mean we shouldn't try.

Utah Open Source Conference 2009

Tue, 15 Sep 2009 16:18:00 GMT

Just wanted to post a blurb saying that there will be an OpenVZ booth at the Utah Open Source Conference 2009. I will also be giving a presentation entitled, Introduction to OS Virtualization, Containers, and OpenVZ.

So, if you live anywhere near Utah or the mid-west, please try to attend and stop by the booth and say hello.

What: Utah Open Source Conference 2009
When: October 8-10, 2009
Where: Miller Campus of the Salt Lake Community College

See links above for more details. I'll be driving from the Bozeman, Montana area which is approximately 413 miles.

FUDforum upgrade and troubles

Thu, 09 Jul 2009 13:59:32 GMT

I finally did an upgrade of forum software used on forum.openvz.org. As any big upgrade, it went not so flawlessly as I wanted it to. Read on for some details.

The first problem is "Compact messages" operation caused all the messages to, hmm, be ultimately compacted, or in plain words deleted. Have restored it from the backup, so a few messages written after the last backup were lost. I apologize if it caused any problems for you. Some people may still find messages that

Next problem is forum theme -- basically you have to recreate it from scratch, haven't done that yet, still thinking of what layout will be more convenient.

Yet another problem we found only today is with private messaging, basically rendering it useless. The thing is, a new version of forum software introduced a separate limits on total size of private messages for admins and moderators. Strange enough, upgrade script did't care and just set the new values to zero! Tracked it down by reading the source code, fixed the limits, problem solved. Fortunately no one has seen it, except for the admins and moderators -- which is kinda funny.

Also, I fixed a bug in the forum code (well, technically not a bug but a bad interaction of old version of PHP vs. forum software) which prevented indexing of non-latin (i.e. cyrillic, i.e. russian) messages. So now it's possible for Russian-speaking users to use search.

Finally, I am still a bit unsure if the forum functions fine after the upgrade. So if you find any problems with forum, please let me know.

wiki spam fighting

Mon, 06 Jul 2009 15:50:46 GMT

Yet again I spent almost full working day trying to improve antispam protection on wiki.openvz.org.

Currently 99% of all spam on the web is link spam -- bad guys are adding lots of links to the sites they promote in order to increase page rank values for that sites. In fact they get no profit from that, since in all recent mediawiki installation (including wikipedia itself) all the external links comes with ref="nofollow" attribute. That attribute is respected by Google crawler and other such bots and basically means "ignore this link".

Nevertheless spammers keep inserting trash into such wikis. Recently such activity mostly comes in a form of a user page (or user talk page) creation that looks like, well, a legitimate user page (something along the lines of "My name is John Doe, I'm Java coder, my hobbies are swimming and fishing") but with a blatant plug added ("Here are some cool sites: [1] [2] [3] ...").

For about 2 years or so wiki.openvz.org asks you to login/register in order to edit, so anonymous edits are not allowed. That helps a bit, but still there are bots that performs register, log in and post.

So now I have added another restriction: users that have just registered can not create new pages. Here "just registered" means "registered less than 24 hours ago". Note that such users can still freely edit existing pages. Let's see if it helps.

Oh, almost forgot to say it: looks like captchas don't work at all! Either spammers have good OCR tools, or they hire enough human beings to "manually" decipher those cryptic images.

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.