An Overview of Virtualization Technology

Jane Walker writes to tell us that TechTarget has a short writeup on virtualization and some of the ins and outs of using this technology effectively. From the article: "Virtualization is a hot topic in the enterprise space these days. It's being touted as the solution to every problem from server proliferation to CPU underutilization to application isolation. While the technology does indeed have many benefits, it's not without drawbacks."

Good reading until the end

[tinkertim]

From TFA:
>>>>>
  Novell is investing lots of effort in optimizing Xen specifically for running a virtualized copy of NetWare on top of Linux. The company's goal is to provide its customers with a migration path over to the Linux platform without giving up NetWare.
>>>>>

One of the many un-sung uses for Xen is a swiss army SAN. I'm glad to see someone touch on this.

>>>>>
If you want to use Linux as your host OS, you'll definitely have to go with VMware.
>>>>>

That wasn't so cool. I appreciate the fact that there are just too many products available to touch on everything in one short summary article / writeup, and while the majority of the article was informative even to the lay person, you need to end a sentence like that with a 'Because .... [summary]'. That's a really broad and sweeping statement to make.

Or perhaps even "I recommend VMWare" would have been better.

It looks like the author lost interest in what they were writing near the end of the article. They talk about IRC or newsgroups being the only support options available for OS products [another sweeping statement], however have you checked out the wiki at xensource.com [xensource.com] lately?

Just seems like TFA lost coherency after 'What's best?' It went from really informative to misleading rather quickly. If your going to go to a virtualized platform you owe it to yourself to spend a month trying each candidate to see what works best for you, not the author of whatever article you read :) This is not a pro Xen rant but I'd like to point out that it does install effortlessly on most Debian systems in under an hour, the TFA sort of indicated otherwise.

Piss Poor Article

[HoofArted]

Not much in it, is there? The outcome ... "it depends".

Re:Psst. btw

[Decker-Mage]

With VMWare Server (ex-GSX) switching to free status, frankly I don't think they had a choice. I've been working with, and beta-testing for years, with both and the VMWare product still wins in my opinion. No win situation for MS.

Re:Psst. btw

[LarsWestergren]

Psst yourself.

You have to pay for the OS to run the virtualisation server on, you have to register to download it, and then you have to follow the usual licences- i.e (From MS own Virtual Server 2005 Technical Overview White Paper):
* you may not transfer original OEM server licenses from one computer to another,
* Each installed copy of Windows Server must be separately licensed. This means, for example, that if you are setting up four virtual machines within Virtual Server 2005 to run one instance of Windows 2000 Server and three instances of Windows NT Server 4.0 concurrently, you will need one Windows 2000 Server license and three Windows NT Server 4.0 licenses, in addition to the Windows Server 2003 host license running Virtual Server 2005.
* Each additional licence such as for IIS or databases have to be paid for each virtual machine... and so on.

Yeah, that sounds like an awesome deal.

Re:previous hot topic: virtual reality

[Decker-Mage]

If you play in the Enterprise space, virtuationization can be a god-send, just on the basis of server consolidation alone. Where I play, systems security from SMB to Enterprise, I've been doing some interesting work on developing bastions (no relation to the Linux setup with the same name, think the Military Engineers Vauban and Michelangelo) that I think will play well once fully worked out. Heck, even on a consumer machine, if all internet work is done in a VM, you cut the risk of infection by a wide margin. Those are just a three sample ways to go with this technology. Virtuationzation just gives you more interesting capabilities.

Just my $.02

Re:Good reading until the end

[Anonymous Coward]

I found the entire article to be almost content free. This is the sort of thing that PHBs like to read to feel they're "staying in touch" with technology.

For example, there was no mention of the reason behind the performance differences between VMware (ie. you're emulating everything, right down to the CPU) and Zones (ie. you're running one kernel and only jailing processes).

Fortunately, it was short enough that I could get to the end without wasting too many seconds of my life. But the /. keepers really ought to think twice before posting articles like this, even on a slow news day. It does nothing to improve the image of the site.

Netscaping

[Savage-Rabbit]

Microsoft has made their server virtualization software available for free.

Isn't this the opening phase of what Computer Business Review calls 'Netscaping' the competition? I wonder if that word will ever make it's way into the Microsoft system spelling dictionaries?

Re:Which is missing a QEMU trick

[Cytlid]

I've been working with VMWare and virtual servers for a while now (Xen still won't run on my main workstation at home, some ACPI problem or whatnot), but I was really amazed at QEMU. I never really tried it until I read this month's issue of LinuxJournal (all about Virtualization!) ... some of the Xen and VMWare stuff I was already familiar with.

QEMU's ability to emulate other CPUs is invaluable. You can emulate a MIPS architecture and test your favorite Linksys firmware (I believe the OpenWRT guys already do this). I would really like the m68k emulation to stabalize so I can run old Amiga stuff (or try linux on m68k). Or emulate an ARM processor , drop a PocketPC firmware on it, and test drive Windows Mobile software (or porting Linux to those devices). The possibilities are endless.

Re:I think we've heard this before

[LurkerXXX]

A virtualisation solution running on Windows with, say 5 instances of Windows. That's 6 copies of patches to apply, resulting in at least 11 reboots (1 for each instance and 1+5 for the primary OS).

6 copies of patches to apply? Um no. Any admin working with that kind of setup SHOULD know about WSUS server and be rolling out patches (after he's evaluated them on a test rig to make sure they don't break any of his company-specific software) automatically.

And no, it's not 11 reboots. That's a really really dumb way to do it. You set a group policy to prevent the machines from automatically rebooting after patch installation. When it's time for the scheduled maintenence you shut down all the VM's, reboot the host OS, then crank back up the VMs. That's a total of 6 reboots for 6 windows machines.

Virtualisation is a fun toy and may be a useful tool if you're a multi-platform developer. But it does not seem to be a serious enterprise solution for the datacenter.

Virtualization IS a serius enteprise solution. Lots and lots of us have it in production. Then again, we know a bit about the field and don't patch every machine by hand and do unneccessary reboots.

The cost savings are real if you hire someone competent to run the machines.