Desperately Seeking Xen

AlexGr sends us to an excellent article on the state of Xen by Jeff Gould (Peerstone Research). He concludes that the virtualization technology has some maturing to do and will face increasing competition for the privilege of taking on VMWare. Quoting: "What's going on with Xen, the open source hypervisor that was supposed to give VMware a run for its money? I can't remember how many IT trade press articles, blog posts and vendor white papers I've read about Xen in the last few years... The vast majority of those articles — including a few I've written myself — take it as an article of faith that Xen's paravirtualizing technical approach and open source business model are inherently superior to the closed source alternatives from VMware or Microsoft."

Comments

Re:Need a special processor

[Mostly a lurker]

It is true that Xen requires special hardware to legally run MS Windows. It is also better for performance, generally, to have such hardware. However, there is nothing stopping you from running Xen on pretty much any computer you are likely to own as long as the VMs are Linux based.

Re:vm ware

[Per Wigren]

If you want to run multiple linux instances on the cheap then xen is the way to go at the moment. Except that OpenVZ is a better way to go in that case. If you are only going to run multiple instances of Linux, with OpenVZ you don't need to preallocate a fixed amount of memory for each VM, the root filesystem can be a subdirectory of the root OS instance's filesystem, among many other things. It can do just about everything that XEN can do, including live migration to other physical nodes.

Re:what went wrong is

[stevey]

Not true.

If you have VT-capable hardware then you can run Windows under Xen. You do need the hardware to support it though, and that is a problem for some home users. Recent AMD and Intel chips have slightly differing VT support but both work.

I run Xen at home along with xen-tools (which I wrote) to easily create new Debian guests on demand. These are used for software testing, hacking, and general service isolation.

I think Xen is just now reaching "mainstream" in the sense that you don't have to be an early adoptor or major tinkerer to get it working. Now that distributions are including Xen kernels in their newer releases it really us available for all.

Using it...

[dmayle]

You can choose to believe the hype or not, as you wish, but I'm using Xen in my production environment, and it's simply fantastic. I've got friends with companies who are doing it as well, and it really changes how you think about administration.

Of course, there are some learning curves. For example, how you manage 3-7 servers is completely different from how you manage 20-30, even if they are all virtual. There's a lot more emphasis on system images, isolating functionality, reproducing configurations. On the other hand, dev environments are so much easier to build-up and tear down.

I just wish the OpenBSD port was in a usable state. The mercurial servers hosting it are often down, and even when they're up, I haven't been able to get a working kernel compiled from the sources (even after doing some of my own bugfixes). And last I saw on the Xen lists, Christoph Egger (the guy doing the OpenBSD port) submitted a security patch related to stack slamming, and the Xen guys were kind of like, "meh, security's not really a priority..."... Oh well, here's to keeping my fingers crossed

The Problem With Xen

[Aeonite]

Is that Gordon Freeman ruined it.

Re:vm ware

[gtrubetskoy]

Except that OpenVZ is a better way to go in that case. For fairness it should be mentioned that aside from OpenVZ there is also Linux VServer which does a few things better than OpenVZ (though OpenVZ does some things it does not). Our preference has always been VServer, it's a well-run project with emphasis on quality and well thought through design rather than quantity.

Xen (and virtualization) is for the Enterprise

[xzvf]

While it might be nice if all these things are easy and work well for the hobby crowd, the real money in virtualization is in the enterprise space. Most servers in enterprise environments run 15% max and are refreshed every 3-5 years. The special processor matters less in that case, and the competition is between a mature VMWareESX server (not free), a hardware based IBM and Xen. Microsoft is a surprisingly minior player. VMWareESX server is very good for x86 consolidation and saves customers money, but is very expensive. It is still the best option for Intel based consolidation. Xen has deep penatration in enterprise lab environments. It is just getting the enterprise management tools to move into real production. IBM is very good at virtualization and stability, but on proprietary power and mainframe hardware. Xen will be fine, because the market is very immature, but expect more seamless and non-attrusive virtualization on the desktop.

Guaranteed Results

[catdevnull]

If you want to get a colorful thread of comments started on slashdot, there are 3 ways to do it with guaranteed results:

1) Say something bad about linux (or about Apple).

2) Say something good about Microsoft (or about Apple).

3) Throw a grenade in the room about Open Source software like this:

The vast majority of those articles -- including a few I've written myself -- take it as an article of faith that Xen's paravirtualizing technical approach and open source business model are inherently superior to the closed source alternatives from VMware or Microsoft.

I'm not making any value judgements here--I'm just amused.

Re:Xen "Just Works" (I know. I use it every day)

[div_2n]

The only exception is the deployment of Zimbra I'm going to do. It requires Redhat Enterprise Linux 4 and NPTL

Last I checked, Zimbra runs on Ubuntu 6 just fine.

Re:Xen "Just Works" (I know. I use it every day)

[eno2001]

It depends on what I'm doing. If you weren't trying to be cute, I'd say you were trolling. In reality, it's very common practice to use LVM to clone a filesystem, make some changes to the various files that set IP and hostname as well as other unique host settings and bring up alternate "Test" VMs on a Xen box. So some days I might be running three VMs other days eight or ten. It all depends on what I need to do.

As an aside, I forgot to mention that there are NO other products other than VMWare ESX that offer "live migration" of a running VM from one hardware host to another. That's right... you can take a VM that is running with many users actively using it and move it from one physical box to another with only a few milliseconds down time. The users NEVER notice. The free VMWare server can't do that. Micrsoft's Virtual Server can't do that until they have a hypervisor. And there really isn't anything else that can.

Data Center USA

[fyoder]

I stopped reading the article with this quote:

Oh my. Editable XML configuration files, obscure command line interfaces, grayed out options in the GUI? Thanks, but no thanks. This thing doesn't sound like it's ready for prime time in Data Center USA.

Are sysadmins at "Data Center USA" morons? "Oh nooo, command line time, I hate that. Oh nooo, my option I want is all grayed out! Help me, help me! Oh I am so sad now."

Deploying vm stuff is not the same as using a word processor. "Data Center USA" is in real trouble if their sysadmins aren't any smarter than regular desktop users.