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Red Hat Wants Xen In Linux Kernel

Posted by ScuttleMonkey on from the ground-control-to-kernel-tom dept.

DIY News writes "Red Hat is aggressively pushing to get Xen virtualization technology included in the Linux kernel as quickly as possible. This move comes as Microsoft is pushing its own virtualization products and recently relaxed some of its licensing requirements around Windows Server 2003 to facilitate more pervasive adoption and use of those technologies."

20 of 278 comments (clear)

  1. Xen into kernel by b100dian · · Score: 5, Interesting

    What exactly does "virtualization technology included in the Linux kernel" means?
    That you can run virtual machines with that kernel? that that kernel can be hosted into a virtual machine?

    Or that you can install parallel kernels and run part of the ELF binaries on the other machine?..

    --
    gtkaml.org
    1. Re:Xen into kernel by hey! · · Score: 5, Interesting

      easier management of computing resource, unless I miss my mark.

      In rough terms:

      Admin Cost = N * (H + S)
      where N is the number of computers, H is the network and system hardware admin costs for a single machine, and S is the sys admin costs for the machine. Distributing:

      Cost = NH + NS

      This is a gross simplification, since we all know that complexity is not a linear function of network size, but it will do to be goign on with. Now we take NH and by virtualizing the machine it becomes simply H, so

      Admin Cost (multiple virtual machines) = H + NS

      Basically, I think it'll be common practice in the future to create virtual machines out of thin air by copying a config file or some directories on a machine with available bandwidth. If the cost of enough surplus hardware is less than (N-1)H, then wouldn't it be cheaper to virtualize?

      Of course the complexity is that costs aren't linearly related to N, or for that matter constant in the size and class of machine you are managing. Which is another way of saying YMMV. I think there's clear application in many kinds of situations, for example in software development where we're constantly worried about the various combinations of software our work will have to coexist with. It'd be very convenient to be able to pull a certain system configuration out of a library and have it up in a few minutes, then trash it after a few hours of use. But it may have potential in production environments too.

      --
      Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
    2. Re:Xen into kernel by secureboot · · Score: 3, Interesting
      Check out the Xen User Manual. Look at the xm commands possible. You'll see one is save/restore. That is what implements the functionality I'm talking about.

      Another responder mentioned live migration being much harder - he's right. He's also right when he says this is also done, with some really, extremely, very cool results. You can migrate a Quake server from machine a to machine b iff you assume some SAN or NAS in 60ms downtime, PRESERVING NETWORK CONNECTIONS. That means if you're remotely logged into a virtual machine, and it migrates from machine a to b, you won't get logged out of the virtual machine!

      This is ridiculously cool technology. Take note everyone. It seems like 80% of comments here are incorrect, however. Read the papers on the Xen site if you want to know how paravirtualization actually works. It takes time, but if you're interested, it's worth it.

  2. Two birds, one stone by bernywork · · Score: 5, Interesting

    Not only do they get the ability to knock the shit out of Microsoft, by taking away the base platform from them, they also get to try to get some market share from VMWare.

    Imagine if you would the ability to use Xen for unlimited operating systems, no licensing cost of the base OS, thinking about it, I would prefer to be in Microsoft's shoes as opposed to VMWare's. Only difference is that Xen when compared to VMWare is a very immature platform and no IT manager is going to take Xen over VMWare just yet (Unless cost is a BIG factor).

    I would have to say that this is still very cool, with all the new Virtualization options come out in the new cores shortly and if they can get to market before Microsoft, this is a great way to pick up some customers. Kudos to RedHat and IBM and Intel and everyone else for making this happen.

    --
    Curiosity was framed; ignorance killed the cat. -- Author unknown
    1. Re:Two birds, one stone by b100dian · · Score: 3, Interesting

      no IT manager is going to take Xen over VMWare just yet (Unless cost is a BIG factor)
      With VM Player and vi you may get a free virtual machine.. see http://b100dian.lx.ro/wordpress/index.php?p=90

      --
      gtkaml.org
  3. The irony by Alioth · · Score: 4, Interesting

    The irony is that Microsoft provided some of the funding for Xen (probably for the early experimental Xenised versions of Windows XP). Yes - Microsoft does fund GPLd projects. Often in a company that big, the left hand doesn't know what the right hand is doing, so whilst Gates/Balmer spout off about how evil open source is, another part of MS is funding it (or even releasing it on Sourceforge).

    --
    Oolite: Elite-like game. For Mac, Linux and Windows
  4. It means by Anonymous Coward · · Score: 3, Interesting
    in part making Linux aware of the virtual architecture provide by Xen, not by Intel or AMD. Some of it is for better performance. Some of it is to make it just work. The latter is more worrying since there may be serious security issues as one of the major advantages of VM should be better security than that which is provided by Linux to begin with.

    The other problem here is there are other VM's out there and they all have different requirements for kernel modifications so talk about mess.

    The major underlying problem there is Intel and AMD just don't get it. They put in some rather pathetic and lame support for virtualization and think they're all done with it. They have this Not Invented Here attitude that has kept them ignorant of virtualization technology that has been around for decades and doesn't have as much of these problems.

  5. Why Xen and not vservers? by ptaff · · Score: 3, Interesting

    While Xen appears as a neat package, why choose Xen instead of vservers?

    The hardware cost of running multiple copies of the same OS with vservers is smaller than Xen - there is one and only one copy of glibc in memory, one and only scheduler, and so on.

    1. Re:Why Xen and not vservers? by tbcpp · · Score: 3, Interesting

      We have a X terminal server here at work that uses vservers. Doing it over again, we would probably use Xen as opposed to vservers. The vserves have weird bugs once and awhile. Such as processes not being able to talk to eachother for nor apearnent reason. The entire system will work fine for weeks, but once and a while there will be a problem that nothing short of a restart of the vserver will fix. If Xen works, and you aren't short of resources, use Xen by all means.

      --
      Man is the lowest-cost, 150-pound, nonlinear, all-purpose computer system which can be mass-produced by unskilled labor.
  6. Re:Umm by LaughingCoder · · Score: 3, Interesting

    I am having trouble understanding the rules of engagement. If MS "gives away" IE for free, they get called to task. If they "give away" Media Player for free, they get in hot water. Now why exactly would giving away virtualization not result in the same harsh treatment? Is it because there aren't established for-profit companies in that space already? How about VMWare? If MS gave away virtualization, the "anti-trust" crowd would drag them into court faster than you can say "billable hours".

    --
    The more you regulate a company, the worse its products become.
  7. Mandriva 2006 includes Xen by general_boy · · Score: 4, Interesting

    Mandriva Linux 2006 includes xen0 and xenU-enabled kernels and the Xen supervisor utilities package. The Community version of Mandriva 2006 can be downloaded from many Linux mirror sites.

    I'm running such a box now with a total of three Linux domains (one host domain and two guest)... much easier than manually patching everything.

  8. ITLB/DTLB by Anonymous Coward · · Score: 1, Interesting

    How about fixing Xen to properly emulate the Intel x86 (post-Pentium-Pro) split-TLB architecture, so things like PaX will work in the VM? QEMU and Bochs also fail to do this, opting to use a single TLB instead. Until this is implemented, I'll be forced to continue using VMWare.

  9. How does virtualization work? by DoofusOfDeath · · Score: 2, Interesting

    It basically lets you run multiple instances of the OS concurrently, where each instance thinks it's the only one running on the computer, right?

    But then what do you when two or more OS instances want to monkey around with hardware that has state? For example, if one OS wants the screen resolution to be 640x480, and another OS wants the screen resolution to be 1024x768, you can't very well keep switching the screen between those two resolutions every time you change which OS is getting CPU time. Or another example is with printing: you can't very well interleave the print data streams from two OS's to the printer without hosing the print jobs.

    1. Re:How does virtualization work? by LiquidCoooled · · Score: 2, Interesting

      Print jobs are not an issue, the printer is just busy and the OS in question queues it.
      As for varying screen resolutions, it just made me think of the Amiga and pulling down a low resolution screen to reveal a high res on behind.

      very very cool stuff, but inherantly impractical, I imagine it will most likely be similar to the KVM switching or simple desktop switching?

      --
      liqbase :: faster than paper
    2. Re:How does virtualization work? by digitalhermit · · Score: 3, Interesting

      Virtual machines also have virtual screens that are independent of each other. You can, for example, have a 800x600 window right next to a 1024x768 window. Depending on how you have it configured, toggling between full screen sessions of the VM will either re-size the screen or play inside a portion of the existing screen. It's still virtual video, however, so there's no conflict.

      For printers you can either set up a print server or the printer gets attached to a particular OS instance.

  10. Re:Forking? by m50d · · Score: 2, Interesting

    Because that's bad for the community, something redhat cares about, even if the kernel developers don't seem to. They probably will ship their own xen version for the moment, but the less difference between their kernel and the mainline one the better it is for everyone.

    --
    I am trolling
  11. MS leapfrogging by MobyDisk · · Score: 2, Interesting

    I know everyone complains about how MS lacks innovation, but this is a good example of BUSINESS innovation. Virtualization isn't new. I've used it before, seen it before. But MS bought an existing product, then wrapped it up nice and pretty and easy, and presented it as a solution to a major problem. And it is getting widely adopted. My office uses virtual servers constantly to simulate production environments for development: it saves time, money, and effort.

    I never even considered virtualization of servers or development environments until I learned about MS Virtual PC and MS Virtual Server. Norton Ghost or dd dumps were all that I knew. So Microsoft is doing something right, and they will be perceived as the innovator and the winner here. They will be selling that you can virtualize servers to save time and money, and companies will buy it. They won't even know that this originated in the *nix world.

    I look forward to seeing what the next leap in this technology is. I suspect we are just beginning to see some novel uses for it.

  12. Re:Usermode Linux already in the kernel. by zeromemory · · Score: 4, Interesting

    These guys(Xen) have all these companies donating money to them, but have been beaten to kernel inclusion by UML.

    Being the first to the party doesn't always mean you're going to the best; see DevFS vs. udev.

    Xen has much greater performance than UML and supports more operating systems. While UML is currently more mature and stable than Xen, it's only a matter of time before Xen surpasses UML as the preferred virtual server technology. Hell, even Linode, a strong proponent of UML technology and virtual server hosting provider is migrating to Xen.

    FYI, I'm currently running a Xen-based system with 15 virtual server instances for a system administration course at UC Berkeley on a server built with cheap off the shelf components (AMD Athlon 64 2800+, 1 GB RAM) and everything is quite snappy. It'd be difficult to even approach such usability with UML, and I'm using Xen 2.0.7. I can't see what Xen 3.0 will bring.

    --
    I'm Trappped at Berkeley.
  13. I'd rather see Linux VServer included by gtrubetskoy · · Score: 4, Interesting

    There are a few problems with Xen. First, it's i386 only. Second (and this is the biggest problem IMO) - Xen is venture-backed, and seems to be extremely eager to show their investors a return. Nothing wrong with that, but it's important to consider the motivation, and the consequence of a funding pull back. If XenSource does not turn out to be a great business, then will Xen still be developed and maintained? Why not wait a little bit, in the open source world quality over quantity matters and time pressure should not influence development.

    Also, there is another project that I plug every chance I get - Linux Vserver. Unlike Xen, this is a purely volunteer effort, and is very innovative and attemtps to solve a difficult issue. Unlike Xen, these guys actually do not want to be in the mainline for now, becuase they think it will slow down development. Because Linux VServer is taking a different approach to virtualization (better known as separation, which was pioneered by FreeBSD jails and is also now supported in Solaris), the end result is cross-platform, i.e. runs on any architecture that Linux runs on.

    Now in the past whenever I posted about Linux VServer a lot of folks said that Xen allows you to run multiple operating systems and that that is why it is so useful. I think that in reality running multiple OS's isn't all that valuable - the only case where it may be very useful is software development, but that's a tiny fraction of the Linux users. We've been using Linux VServer for hosting, and we are absolutely convinced that this is the right solution - for using Xen for example would introduce all kinds of problems (starting with resource bloat).

    Yet unfortunately the OSS world has become PR driven lately. Very few people are technically capable of looking at things based on its merits and just go after the things that have the most buzz, not realizing that the buzz is artificially generated.

  14. Volunteer efforts can fall apart, too by robla · · Score: 2, Interesting

    Why is it that you consider an all-volunteer effort inherently more robust? Key volunteers can have life changes (job change, health, etc) that cause their involvement to change. VC projects have the benefit of providing dedicated staff, professional project management, business development and marketing to keep momentum alive.