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Xen 2.0 Virtual Machine Monitor Released 199

Posted by michael
from the xen-and-the-art-of-system-maintenance dept.
An anonymous reader writes "The Xen team are pleased to announce the release of Xen 2.0, the open-source Virtual Machine Monitor. Xen enables you to run multiple operating systems images concurrently on the same hardware, securely partitioning the resources of the machine between them. Xen uses a technique called 'para-virtualization' to achieve very low performance overhead -- typically just a few percent relative to native. This new release provides kernel support for Linux 2.4.27/2.6.9 and NetBSD, with FreeBSD and Plan9 to follow in the next few weeks. Xen 2.0 runs on almost the entire set of modern x86 hardware supported by Linux, and is easy to 'drop-in' to an existing Linux installation. The new release has a lot more flexibility in how guest OS virtual I/O devices are configured. For example, you can configure arbitrary firewalling, bridging and routing of guest virtual network interfaces, and use copy-on-write LVM volumes or loopback files for storing guest OS disk images. Another new feature is 'live migration', which allows running OS images to be moved between nodes in a cluster without having to stop them. Visit the Xen homepage for downloads and documentation."
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Xen 2.0 Virtual Machine Monitor Released

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  • by gowen (141411) <gwowen@gmail.com> on Friday November 05, 2004 @10:16AM (#10733759) Homepage Journal
    What is the sound of one hand crashing?
  • Alas, no Windows... (Score:5, Interesting)

    by October_30th (531777) * on Friday November 05, 2004 @10:16AM (#10733760) Homepage Journal
    A port of Windows XP was developed for an earlier version of Xen, but is not available for release due to licensce restrictions

    Sigh... how hard would it be to get a license and distribute it as a binary-only module to people like me who'd be willing to pay for it? I'm sure it'd still be less expensive than the existing alternatives.

    Otherwise this looks very nice. In fact, I didn't know that there was such a mature free virtual machine available.

    • by Frasier (67878) on Friday November 05, 2004 @10:29AM (#10733843) Homepage

      Sigh... how hard would it be to get a license and distribute it as a binary-only module to people like me who'd be willing to pay for it?

      Microsoft has their own virtual server product. They propably do not want competition, especially something that allows one to run Windows XP and Linux on the same machine at the same time.

      I would personally love to have access to a Windows system without having to dedicate entire machine for it. But Microsoft has not, is not, and propably will not show any signs of willingness to cooperate with non-Microsoft systems.

    • you can run xp in vmware

      you can have more than one vmware running on the same machine

      vmware runs on linux and on xp (different versions though) but is not free software
      • Yes. I know. I bought and used a copy of VMware before the price went through the roof.

        As I said above, I don't think that Xen + licensed Windows-compatibility module would cost as much as VMware and other alternatives.

    • by petaflop (682818)
      Which is very interesting, given that that project is sponsered by the EPSRC (Engineering and physical sciences research council) and Microsoft UK. See page 11 of the White paper [cam.ac.uk] for details.
  • Obligotory. (Score:5, Funny)

    by Anonymous Coward on Friday November 05, 2004 @10:16AM (#10733761)
    Oh man, can you imagine the overhead on a virtual beowulf cluster using this?
    • Given the tasks that the average /. reader would actually be trying to run on a Beowulf cluster, there would be no loss of efficiency. :)
  • by grub (11606) <slashdot@grub.net> on Friday November 05, 2004 @10:17AM (#10733767) Homepage Journal

    So from a Linux or Plan9 VM I can watch the BSD VMs die in realtime!

    disclaimer: I love OpenBSD
  • 64 bit? (Score:3, Interesting)

    by gr8_phk (621180) on Friday November 05, 2004 @10:17AM (#10733768)
    Does it work with AMD64? How about with one 64 and one 32 bit OS? The FAQ just says "x86".
    • Re:64 bit? (Score:3, Informative)

      by Orgazmus (761208)
      AMD64 is x86-64, and yes it is x86-compatible.
      It should work
      • Re:64 bit? (Score:3, Informative)

        by isolationism (782170)
        Being an Athlon 64 Socket 939 owner I tried to do just that -- unfortunately it didn't compile cleanly "out of the box" (at least, for me) just yet, it errors out on compiling file_stream.o because of something to do with libxutil.so.

        You could probably compile it fine in a 32-bit chroot or something, but I'll leave that to someone else to try. I'm happy to wait for release 2.x for full AMD64 support.

        Of course, don't let me stop you from trying. Anyone who does get it to compile, let us know what you did

    • Re:64 bit? (Score:5, Informative)

      by julesh (229690) on Friday November 05, 2004 @10:23AM (#10733804)
      From the manual:

      A port specifically for x86/64 is in progress, although Xen already runs on such systems in 32-bit legacy mode
  • by spidergoat2 (715962) on Friday November 05, 2004 @10:19AM (#10733781) Journal
    It can't run AmigaDOS.
  • by slashnik (181800) on Friday November 05, 2004 @10:21AM (#10733797)
    from http://www.cl.cam.ac.uk/Research/SRG/netos/xen/faq .html

    1.3 Which OSes run on Xen?
    To achieve such high performance, Xen requires that OSes are ported to run on it. So far we have stable ports of Linux 2.4, Linux 2.6, and NetBSD. Ports of FreeBSD and Plan 9 are nearing completion.
  • Not as cool. (Score:5, Informative)

    by Anonymous Coward on Friday November 05, 2004 @10:23AM (#10733809)
    From the FAQ, it states that you can only run OS's ported to it. While this might be great for cluster testing, or software design, this is defintely no VMware replacement. I am slightly disappointed in this, but I can see where it has its place.
    • Re:Not as cool. (Score:4, Informative)

      by frenetic3 (166950) * <houston@nOspaM.alum.mit.edu> on Friday November 05, 2004 @03:56PM (#10736939) Homepage Journal
      No, no... This is HUGE for virtual hosting/virtual private server providers (i.e. web hosting providers that provide you with a virtual machine on which you're root, not some locked down /home directory with a million other people.) VPS'es allow you to run whatever distro you want, be root, run whatever PHP/Python/MySQL versions you need, etc. Basically (IMO) the control and flexibility of a dedicated server without the nightmare of having to replace faulty hardware or dealing with random outages. I have one for the company I run (until it gets too large for a VPS).

      Hosting providers have used UML (and maybe VMware) for this but it's comparatively too slow. Virtuozzo [virtuozzo.com] does this (and is successful, and charges a fair amount of $ for it), so they must be shitting bricks right now.

      -fren
  • by ites (600337) on Friday November 05, 2004 @10:32AM (#10733870) Journal
    Big difference. VMWare is about virtualising a foreign OS. Since VMWare abstracts at the BIOS and hardware level it can run almost all OSes the CPU will support but it takes a large performance hit.

    Xen is a VM platform, i.e. it lets you set up multiple virtual machines that run with very little extra overhead. A lot like User Mode Linux, except easier to configure and install.

    Here's a typical use case: you want to make a network "security box" that includes firewall, proxy, web server, email, wiki, irc. Now, conventionally you put all these services in the same Linux system (or whatever OS you use). Using Xen you run all of the services in their own virtual machine, so that if the firewall gets compromised, for instance, an attacker cannot get access to other parts of your system.

    It's a very useful tool.

    Oh, another use case I just thought of too: how about a 'hidden' Linux OS on your Windows box that does all your email, browsing, and other Internet work that you want to keep secure. Click the icon, up pops Mozilla, except it's running in a different virtual OS.

    Yup, definitely very useful.
    • We already have something much more useful tool for that: cygwin. THE way to compile and run native linux apps on windows without wasting an excessive amount of systeml resources.
      • We already have something much more useful tool for that: cygwin. THE way to compile and run native linux apps on windows without wasting an excessive amount of systeml resources.

        Err.. right. Cygwin does not run "native linux apps". It is a POSIX compatible C library combined with a VFS layer that presents a Unix-like filesystem when run on Windows. It has nothing to do with Linux, the only thing about that is native is that it is a piece of Windows software that runs on Windows. And given the slow im
    • Oh, another use case I just thought of too: how about a 'hidden' Linux OS on your Windows box that does all your email, browsing, and other Internet work that you want to keep secure. Click the icon, up pops Mozilla, except it's running in a different virtual OS.

      Or the reverse.. run XP on top of Linux for the few apps that need it. Though I don't think Microsoft will allow that to happen. The Xen guys have XP working as a virtual OS in their labs, but for obvious reasons they can't release that.

    • Here's a typical use case: you want to make a network "security box" that includes firewall, proxy, web server, email, wiki, irc.

      My preference for this would be Linux VServer [linux-vserver.org] or jails on BSD which have practically no overhead. Xen would only be useful if the requirement is to run different OS's on the same machine.

      • Or if you wanted to run different distros. Or if you wanted to isolate virtual server kernels from each other since it HAS been known to have a kernel flaw that let a jail/vserver into the other vservers. From a security standpoint, I wouldn't sell virtual servers like vserver. It's just asking to get your ass handed to you by a hacker in my experience. 8-P With xen, even if you get a root comprimise, or a kernel comprimise, the individual domains are isolated from each other in such a way as to prevent o
    • Here's a typical use case: you want to make a network "security box" that includes firewall, proxy, web server, email, wiki, irc. Now, conventionally you put all these services in the same Linux system (or whatever OS you use). Using Xen you run all of the services in their own virtual machine, so that if the firewall gets compromised, for instance, an attacker cannot get access to other parts of your system.

      Who in their right mind would ever consider putting a firewall, email, web server, and IRC on the

      • "Who in their right mind would ever consider putting a firewall, email, web server, and IRC on the same box? A *firewall* for God's sakes. I wouldn't put that combination together on any one box, even with Xen 2.0."

        Someone who only has one or two boxes?
    • by Anthony Liguori (820979) on Friday November 05, 2004 @12:03PM (#10734619) Homepage
      VMWare is about virtualising a foreign OS. Since VMWare abstracts at the BIOS and hardware level it can run almost all OSes the CPU will support but it takes a large performance hit. Hehe.. The VMWare marketing guys have gotten you pretty good. What your describing is something called full virtualization. It's what IBM does in PowerPC (with something like the OpenPower platform) and with hardware support can be pretty darn fast. The IA-32 architecture is not capable of full virtualization. If you don't believe me, just read any of the dozens of papers written on the topic. Memory poses a problem (albiet one that's overcomable) but the thing that makes it impossible is the behavior of three instructions. Virtualization's really a simple concept. You run an OS at a lower priviledge than it expects and the priviledged instructions will throw exceptions that can be caught and emulated. Certain instructions on IA-32 silently fail when executed outside of ring 0 making it impossible to emulate those instructions. What tools like VMWare do is run through the executable and change those instructions to illegal instructions or do dynamic rewriting of the executable. That's right, they have to dynamically rewrite the executable. Have you ever wondered why VMWare asks you what OS it will be running? Because it has a big set of tables of where instructions need to be rewritten. Have you ever tried to run a checked build of Windows in VMWare or better yet a newer version of Windows that just isn't supported? It fails miserably. The difference between VMWare and Xen is that Xen accepts the difficulties and then decides that if we're already going to change the OS, let's just make a few more changes to improve performance. Adding VMWare-style virtualization support to Xen wouldn't be that difficult if you have the tables and such that VMWare had. Remember too, VMWare requires OS-drivers to be installed.. there's a reason for that.
      • by TimMann (98520) on Friday November 05, 2004 @12:56PM (#10735114) Homepage
        You're largely (though not entirely) mistaken about how VMware virtual machines work. User code runs in direct execution up to where it tries to make a system call or takes a page fault (etc.) and traps into privileged code. Privileged code is *dynamically* translated at runtime; we don't have big tables that tell us exactly where all the instructions in each supported operating system need to be patched. That would be totally impractical.

        We ask what guest OS you're running because we have certain OS-specific optimizations, things that help one OS a lot while hurting others. Most OSes will run fine (though more slowly) on the "other" OS setting. A small number need specific workarounds that are enabled only if you select the right OS setting.

        Checked Windows builds work fine AFIAK. If you have one that doesn't work, file a bug report. New OS versions usually work without VMware changes, though not always. Sometimes they'll exercise a system feature that is slow until we optimize it more in the next release, or sometimes their drivers will try to use a device in a new way that our emulation of it doesn't yet support.

        We do supply some device drivers for guest OSes, not to work around any shortcomings in our CPU virtualization, but because for performance reasons some of the virtual hardware we implement is not the same as any real hardware that the guest has its own drivers for. The only such devices are the virtual display card (which works as a standard VESA device even if you don't install our driver, albeit slowly), one of the two virtual ethernet cards we support (the other is a standard though elderly AMD card), and one of the two pointing devices (the other is a standard PS/2 mouse). Hmm, I think we also supply some SCSI drivers, but only because some guest OSes don't have good drivers for either of the two standard SCSI cards we emulate (one from BusLogic and one from LSI Logic).

        As you can guess from the above, I work for VMware -- in engineering if that makes me more believable to you, although I haven't encountered our marketing folks lying. Standard disclaimer: I'm speaking only for myself here, not officially for VMware.
    • Big difference. VMWare is about virtualising a foreign OS. Since VMWare abstracts at the BIOS and hardware level it can run almost all OSes the CPU will support but it takes a large performance hit.

      Xen is a VM platform, i.e. it lets you set up multiple virtual machines that run with very little extra overhead. A lot like User Mode Linux, except easier to configure and install.

      Win4Lin is a commercial product with similar goals to Xen, but runs Windows under Linux. Unlike VMware, sound and video run at

  • by a_hofmann (253827) on Friday November 05, 2004 @10:38AM (#10733907) Homepage
    GPLed virtualization software that according to the benchmarks [cam.ac.uk] achieves performance unseen in current approaches - sounds like a dream come true.

    It would be astonishing if those benchmark numbers hold true in a production environment, which might well be as the selected benchmarks (SPECint, Postgres, Apache, ..) should give a fair picture of the overall performance hit for the virtualized systems.

    Being able to partition your OS without serious performance implication would open a whole lot of new possibilities for developers that previously where only possible with huge investments in high-end hardware and expensive virtualization software licenses.

    I've already decided: My price for the most useful opensourced application in 2004 goes to..... Xen :)

    • Just not fair to compare it with vmware workstation 3.2. vmware workstation 4.5 kicks ass.
      • Yes, it is unfair to compare with an old version of VMware. (Probably this is only a license issue, or would you invest 200 bucks for a new VMware version to be able to do up-to-date benchmarks?)

        Still I suspect that the performance gain not to be that huge. VMware is another class of virtualization software that does not only allow you to run different host and target OSs but also to emulate hardware not installed in the system at all.

        As I understand Xen it only does virtualization of the existing hardwar
    • by Anonymous Coward
      I don't have a page you can visit but in practice I was able to run 2x as many virtual hosts under xen than I could with the same hardware under UMLs at even faster speeds. I just ran out of physical memory on the athlon machines is all. :)

      So yeah, the benchmarks really are very close to real world results from my personal experience.
  • Plan9 (Score:1, Insightful)

    by Anonymous Coward
    Does anyone actually use Plan9?
  • I've been wondering for years whether this would be feasible, but my idea was to thread each OS to a different processor. That said, I've never known assembly and have no idea whether I'm being painfully naive here.
  • With this software you can simulater your very own super computer.. thats absolutely great..

    Big glue gene or what ever prepare to die..
  • " A port of Windows XP was developed for an earlier version of Xen, but is not available for release due to licensce restrictions."

    Awe, shucks.
  • Xen? I hated that level - too much jumping. Oh, wait, this is something else, isn't it?
  • QEMU (Score:4, Informative)

    by nns6561 (559085) on Friday November 05, 2004 @11:59AM (#10734600)
    QEMU [bellard.free.fr] is a similar open source project. It's supposed to run unmodified versions of Windows even. Does anybody know what QEMU's lastest performance numbers are?
    • Re:QEMU (Score:3, Informative)

      by dmaxwell (43234)
      Win98 is barely usable on a 2.4 Ghz PIV. It is good for running proprietary groupware clients and the like. The next version will have decent SB16 support and some small performance increases.
    • Re:QEMU (Score:3, Informative)

      by Abcd1234 (188840)
      Actually, it's really that similar at all. Xen is a virtualization architecture that allows you to run "ported" OSs concurrently. QEMU is a full x86 hardware emulator, CPU and all, meaning that the OS thinks it's running on real hardware. VMWare, which is in yet another class, virtualizes the x86 CPU, along with trapping and executing "leaky" instructions (since Intel can't seem to make a real, virtualizable ISA), meaning the majority of the guest software instructions are executed on the underlying CPU,
    • Re:QEMU (Score:3, Informative)

      by oldmanmtn (33675)
      Performance numbers? No. Performance perception: unusably slow.

      I was able to install a recent build of Solaris 10 on it without a hitch, so the functionality seems to be very solid. However, the installation took almost 6 hours, or about 10 times longer than a native installation. Since installation is all about I/O, this doesn't bode well for actually running the OS when the CPU performance will be much more important.

      As for your suggestion that QEMU is similar to Xen: no, it's not. QEMU emulates th
  • If you can run Xen running 32-bit Linux under a 64-bit version of Linux? I've got a case where a user wants to run Matlab (6 I think) on his shiny new 64-bit Linux machine, but it just isn't supported.

    I had suggested VMware, but this might be better (performance and price).

  • I use http://www.colinux.org/ [colinux.org] to run linux inside windows 2000/XP. It is free and a lot faster than vmware. You can even download a debian image for a quickstart.
  • Are there any similarities between this and what IBM does on their mainframes [ibm.com]?
  • While its nice to be able to run virtual UNIX boxes, being able to run multiple instances of windows server would be great ..

    Their site mentioned getting XP running, but I don't see the average Joe being able to get a hold of such a modified beast.. ( and server is more useful then a workstation product anyway )

    Oh, and a bsd host would be nice too since I'm making a list :)
  • by arete (170676) <areteslashdot2 AT xig DOT net> on Friday November 05, 2004 @04:02PM (#10737000) Homepage
    I'm looking to do exactly what User Mode Linux claims to be for, but it seems like Xen does it too. Which is more reliable? Faster? Easier to install?

    Basically I want just slightly more functionality than a chroot jail - I want to be able to run a service on a virtual filesystem (ie, a filesystem that exists as a file) with an linux OS version that may vary from the host OS (ie, I can upgrade one service without having to do them all at the same time) I want a compromise of one service to have minimum security implications for the others. And I want to be able to move a service/virtualmachine from one physical machine to another with a minimum of hassle.

    Thanks in advance!

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