Wikimedia Simplifies By Moving To Ubuntu

David Gerard writes "Wikimedia, the organization that runs Wikipedia and associated sites, has moved its server infrastructure entirely to Ubuntu 8.04 from a hodge-podge of Ubuntu, Red Hat, and various Fedora versions. 400 servers were involved and the project has been going on for 2 years. (There's also a small amount of OpenSolaris on the backend. All open source!)"

More surprised at the mess they had before

For such a large effort, it seems wild they had so many different distros running in their environment.

What do you guys think?

Re:More surprised at the mess they had before

I think that it's good to standardize on the best OS for your needs, but to find out which one is best you should first try running a bunch of them.

Re:More surprised at the mess they had before

I think it likely that Wikipedia started out as a small pet project, and just happened to grow piecemeal as they needed more and more resources as they grew in popularity. They wouldn't have been sure to start with just how popular they were going to become, how could they? Also take into account that perhaps they had been using different OSes in a consistent way (though I don't expect that to be likely), like some were just for webserving, some held a quick database of current articles, some machines held compressed archives, some were for intended for virtualisation and testing out of new designs, that kind of thing?

Anyone who has written a small well planned (or perhaps not so well planned) application but then been asked to make many, many, many changes over the years will be able to sympathise I expect. It's much easier to design a large coherent system than grow one out of a smaller system..

Re:More surprised at the mess they had before

I believe the devs (the sysadmins at Wikimedia are also called "devs") experimented with a wide range of OSes - various Fedoras, Red Hat, Ubuntu, FreeBSD, Solaris 10, OpenSolaris - in various situations to see what was best to work with. This is a rationalisation from that.

Realistically, it's all Unix and it'll all do the job. So it then becomes a matter of picking one your team is comfortable with. With armchair sysadmins' distro wars, "perfect" is the enemy of "good" - there's nothing you can do with CentOS that you can't also do with Ubuntu, you eventually just have to pick a damn distro and stick with it.

Re:More surprised at the mess they had before

That is an entirely accurate summary of the situation. :) We still have a tiny technical staff, and re-organization of things that got thrown together in a hurry long ago is an ongoing task.

Re:More surprised at the mess they had before

Your mistake is in thinking it's a large effort - they started with just volunteers and then had only one or two full time staff for a while with the technical stuff still being done by volunteers. The first technical person wasn't hired until August 2005, four and a half years after the launch of Wikipedia (which, by that point, was already a top 50 website according to Alexa), they only have around 5 technical staff now. It's a very small project from that point of view, it's just a hell of a lot of servers!

Re:More surprised at the mess they had before

The first technical person was Brion, who'd done the job as a volunteer for quite a while before that.

I started editing Wikipedia in early 2004. I believe they'd just made the radical jump from one box to three boxes.

Now stuff is structured in a horizontally-expandable fashion. "Add some more Squids." "Add some more Apache servers." So a single platform is an obvious win, and picking one platform to standardise on is actually more important than which of various near-indistinguishable free Unix-like operating systems that could all do the job they pick.

CentOS is free RHEL

So it's unlikely the decisions were influenced heavily from a budgetary standpoint. If they wanted to stay with a free RHEL derivative linux that's essentially identical to the one you pay for, they'd be using CentOS. [centos.org]

They chose Ubuntu. Maybe they just like it better? I think you can factor cost of out the equation.

Re:CentOS is free RHEL

Canonical has recently provided us a donated support contract, but that didn't influence our (much earlier) decision to stick with Ubuntu.

Primarily:

• We liked it better
• It's nice that people can run the same version locally (who runs CentOS on their desktop? Playing CentOS vs RHEL just feels like a big fat kludge and tells you there's something broken about the distro.)
• Unlike Debian stable, and like Fedora, it's updated fairly frequently so we get a decent rate of package updates for infrastructure...
• ...unlike Fedora, it's not so bleeding edge that things die all the time (SELinux breaking everything, yay!)
• ...and Canonical actually puts out security updates for a decent amount of time.

Re: Wikimedia Simplifies By Moving To Ubuntu

[citation needed]

Re:And?

In related(ly boring) news, Sun Microsystems replaced 200 old worn-out keyboards on their office workstations. Also, a handful of Microsoft employees patched their OSes, and some guy in Phoenix got a paper cut on his finger.

Re:And?

My finger hurts too. You know those bits of skin just above and behind your nails? Part on that the left side of my left index finger has gotten torn a little and now it's like a flap. The problem is, I don't need to alter the aerodynamics of my finger because I can't fly. It's really just painful, instead of useful, like on an aeroplane.

Actually, does anyone know how that happens?

Re:And?

the cuticle doesn't properly detach itself from the nail as it grows. The nail's growth slowly tears your skin apart.

Re:And?

How is this news?

Well they either should have stuck with 7.10 or waited for 8.10.

That's news...

8.04 is a long-term release. In the world of servers, that counts for something. Also, there were changes from 7.10 to 8.04 that were probably things Wikimedia wanted to take advantage of.

Re:And?

It is when a new license costs $0.00. Other than deployment costs, there's no reason not to upgrade frequently.

There is always risk involved when upgrading or deploying systems. Businesses don't upgrade just for the sake of upgrading. They will weigh the risks against the benefits and proceed if there is a clear advantage to upgrading. Like the saying goes, if it ain't broke, don't fix it [answers.com]. The cost of licenses can be minuscule compared to deployment costs, so much so that many licenses might as well be $0.00. Deployment costs can be some of your largest costs. How many people will it take to upgrade? What is their cost per hour to the business? Multiply that by the number of people involved. Have you deployed on an identical test system and tested your software to ensure that it will continue to function as required on the new production system? Do you have test scripts so that you can validate that it performs as required? Will you have to make changes to software or hardware to accommodate the upgrade? Will you need to update your documentation? What is your contingency plan should the upgrade fail? What will be the cost to the business if the system is unavailable outside of the deployment window?

Some systems, like SAP, may take years to be deployed throughout an organization. Your favorite distro might reach the end of support before deployment even completes. For other systems, your time line for product upgrades and support may not be entirely within your control. What if your system is part of a product that needs approval from the FDA [fda.gov]? With five years of support you may have eaten up three years of that during product development and FDA approval, leaving only two years of support for the OS on your products. That could leave you with a short product lifecycle or mean that you have to perform significant upgrades in the field.

Other operating systems, such as Solaris, Windows, AIX, and HP-UX are supported for 10 and sometimes 12 years. The only saving grace for these enterprise Linux distros is that the source is available. But when the five years are up, then what? Will you still be able to pay Red Hat or Canonical to support your end-of-life Linux distro? What if they have made a business decision not to support end-of-life distros no matter what? If they will support it, it's safe to assume that your support contract will cost more than it did during the previous five years. And if you go somewhere else and hire some linux experts to support your distro, they won't have access to the information that the distro creators have. They won't have the documentation about why certain patches were applied, or specific changes were made, or other internal decisions. You better hope that your new support company is very careful and thorough.

So then, would it have been a better investment to pay for Solaris and 10 years of support, pay for 10 years of Linux support, or pay to upgrade your systems every three to five years? I don't know. It depends on your goals. Clearly Wikipedia likes to move faster than the average business. They seem to be continually upgrading their wiki software and like staying on the leading edge. From reading about their server setup, they appear to have a lot of redundancy and can reduce their risk when upgrading. Three to five years of support for their operating systems is probably sufficient for their needs. But don't let that lull you into thinking that five years is long term.

Re:And?

I'm sure Xorg and KDE4 are high on their priority list for their web servers.

Re:And?

You wouldn't believe how much nicer Squid and MySQL look in Compiz.

Re:did not know that....

I did not know that ubuntu was a player in the server market.

http://www.ubuntu.com/products/whatisubuntu/serveredition [ubuntu.com]

Re:did not know that....

I did not know that ubuntu was a player in the server market.

THIS is what makes it "news that matters".

Re:did not know that....

Actually, the only difference between "Ubuntu Server Edition" and the "regular" Desktop version is which packages get installed by default.

That's one of the things we like about Ubuntu -- the 'supported' version (should you want a support contract, or even just security updates for a longer period!) isn't a totally separate distro from what folks use at home.

When Red Hat split "Red Hat Linux" into "Red Hat Enterprise Linux" (supported, but for $ only) and "Fedora" (free, fast-changing, no long-term security updates), they lost the benefit that techs would likely be running the same version of the software on their desktops and servers.

Re:Is this really a good idea?

I'll probably get modded Troll for this but whatever ...

But as a server distro, I'm not so sure. I'm surprised that Wikimedia didn't go with a distribution that's more established for server needs.

If you have an argument to make about the OS's merits as a server then make it based on facts. Tell us why you don't think it's a perfect fit on the server. Don't just say "I'm not so sure" and leave it hanging there. Support your position with something that can be argued.

Re:homogeneity

Uh, whuh? You've obviously never had to herd a large number of machines. Most stuff running the same OS is the only way to live - jumpstart/kickstart, standard patch clusters, one local package repository server, that sorta thing.

(I do in fact do this for a living. Standardised Solaris 10 servers with Blastwave for the open-source toys, CentOS 4 when we need Linux, local repository servers for both. A few Windows boxes with a locally-served copy of Cygwin on them. May I heartily recommend Cygwin on any Windows servers you may be stuck with - it makes life so much saner.)

Re:How many admins?

Mass installation of a customized distro can do better than mass installation of a general distro (eg, the kernel and software can be optimized for your use case).

And indeed, we use a slightly customized Ubuntu, in that we have our own patched versions of some packages (PHP, Squid, MySQL, some custom PHP extensions, etc) tweaked for performance or features we need, plus custom meta-packages to install the configurations we require on different server sub-types.

This is pretty easy to do on any distro with a decent package manager. I still like apt better than yum, though!

Re:Whither OpenSolaris?

These are on our new image/media-upload fileservers. We're trying out the wonders of ZFS (snapshotting for consistent backups and "rm -rf oops" protection, potentially filesystem-level replication, etc).

Since they're an isolated service type it's not a *huge* burden to have them be a little funky (eg, we don't randomly have an OpenSolaris box in the middle of the Apache/PHP cluster), though if we could do ZFS on Linux without jumping through scary hoops we'd happily to that instead!

We'll try it out for a while, and if we're happy with it we'll keep using it, if not we'll migrate to something else eventually (the machines should as happily run Ubuntu as they do OpenSolaris)

Re:Simple is good

I need to overwhelmingly emphasize that OS X Server is *barely* suitable for a production environment.

I'm a big fan of Apple, and do appreciate the nice GUIs that they provided with OS X Server. However, it's not particularly stable, tends to break at odd intervals, and ignores many common Unix conventions, making it a huge pain to perform certain tasks, or do things not supported by the GUI.

It's a nice start, but I'd be very cautious about adopting it across your entire server infrastructure. Using it to host certain Apple-y apps might be fine, though I'd rely upon Linux/BSD for serious server tasks, especially if you already have the staff/experience to do so.