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Virtualization Linux

Linus Thinks Virtualization Is 'Evil' 330

Front page first-timer crdotson writes "Linus said in an interview that he thinks virtualization is 'evil' because he prefers to deal with the real hardware. Hardware virtualization allows for better barriers between systems by running multiple OSes on the same hardware, but OS-level virtualization allows similar barriers without a hypervisor between the kernel and the hardware. Should we expect more focus on OS-level virtualization such as Linux-VServer, OpenVZ, and LXC?"
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Linus Thinks Virtualization Is 'Evil'

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  • Some might argue (Score:2, Insightful)

    by Anonymous Coward

    That your OS being tied to a particular piece of hardware without a ton of effort is also "evil." Migration is one of the best things ever.

    • by h4rr4r ( 612664 )

      Sounds like your OS needs fixed. I have migrated linux boxes with dd.

      • As have I, and ended up going through a real pain in the ass with udev. Not as bad as migrating Windows, of course, at least Linux almost always boots (in the old days when I used Slackware I used to compile a braindead generic kernel that would pretty much boot on anything and add it to the LILO menu), but still, depending on the hardware, it can be a hastle.

        With virtualization, as long as I stick to a particular virtualization system (generally KVM), so far as the guest OS is concerned, it doesn't know t

      • by b0bby ( 201198 )

        Sounds like your OS needs fixed. I have migrated linux boxes with dd.

        But did you do that while there were live users on the system?

      • "Sounds like your OS needs fixed. I have migrated linux boxes with dd."

        In 2 to 10 seconds? Live? Without people even losing their current open sessions?

        I really don't think so.

      • by micsaund ( 12591 )

        He was 99.99% likely referring to migrating a live VM to another host, not imaging your desktop to another hard drive. In the enterprise, downtime is often not well tolerated (not something I agree 100% but whatever) and live migration (aka VMware VMotion for example) enables you to take a virtualization host and vacate all of the *still running* VMs off to another host when you need to do maintenance or whatever else to the physical hardware. In the case of VMotion, there is a loss of about one ping on t

      • The biggest problem with that is trying to migrate to dissimilar hardware. Changes to the storage adapter or disk size (smaller) make for real problems.

        <shameless plug>Storix [storix.com] is good for migrating to different hardware.</shameless plug>

    • Universe: Replace hardware, rebuild server + much grunting
      Multiverse: Replace Hardware, go to sleep.
    • by sjames ( 1099 )

      Application level migration would be even cooler. Why should migratable resources be arbitrarily glued together into "system images"?

    • Comment removed (Score:5, Interesting)

      by account_deleted ( 4530225 ) on Friday August 19, 2011 @06:10PM (#37148702)
      Comment removed based on user account deletion
      • If you really want to fork the kernel, then go for it. Hire the appropriate people if you don't have or want the necessary skills. If you haven't got the money for that, make a good business case as to why your ideas are better and get some financial backing.

        I'm no expert on ABI, but it looks like there's some projects related to it that are at a higher level than the kernel (e.g. Gnome, KDE etc) which is presumably due to the difficulty of having an ABI on a kernel that supports multiple processor archit
  • Linus is right (Score:2, Insightful)

    by mfh ( 56 )

    The shift towards virtualization represents a further shift in control away from each person towards a reliance on the honest of others.

    • No. (Score:4, Informative)

      by MrEricSir ( 398214 ) on Friday August 19, 2011 @03:44PM (#37147132) Homepage

      Cloud computing != virtualization

    • by Luyseyal ( 3154 )

      Suuuuure, you have 2 CPUs, Mr. Guest OS. *wink*wink*

      -l

    • by 0racle ( 667029 )
      If I run Linux as a host and FreeBSD and Windows in kvm or VirtualBox, to whom have I given up my control too?
      • by arth1 ( 260657 )

        In the case of VirtualBox, that would be to Oracle.

        Can you say with certainty that they will support Windows 9 guests or Linux 3.4, or have you given up the control over upgrades to them?

        • VirtualBox is GPL (extensions aren't, but those aren't needed for core functionality), so really not much control is handed over at all (if Oracle refuses to offer support, the project can be forked.)
        • by 0racle ( 667029 )
          Can you say for a certainty that your current hardware will support Windows 9 or Linux 3.4? Certainly now. Are you CERTAIN unreleased future OS's will support your current hardware?

          No you aren't, you can't be. Oh they probably will, but then again, VirtualBox and kvm will probably support the next few releases of the major OS's as well. So again, what have I given up, other than 2 keyboards and at least one mouse of course? There are many tools out there to convert virtual disks from one format to another
          • by arth1 ( 260657 )

            Can you say for a certainty that your current hardware will support Windows 9 or Linux 3.4? Certainly now. Are you CERTAIN unreleased future OS's will support your current hardware?

            No, but I am certain that I can buy hardware that is compatible.
            With a VM, there are no such guarantees, because there's a lack of purveyors of virtual hardware. It's pretty much only the virtual machine vendors, so yeah, you have to trust them to upgrade whenever necessary.

            There are many tools out there to convert virtual disks from one format to another so moving data to another VM package (if you just had to keep it local to that VM for some reason) is easy, and much cheaper than buying adapters for hardware interfaces.

            Switching to another VM isn't always an option either. So far, none of the VM vendors have provided drivers compatible with Gnome Shell, for example. (Not that gnome shell is essential, but it proves the point by example, I should thi

          • I'm pretty certain that Windows 9 won't support any of my current hardware as 3 of my 4 machines are already too old to run Windows 7 and the remaining one can run it just barely. On the other hand, I'm even more certain that Linux 3.4 will run all of my hardware because my oldest machine was made before Linux 2.2 was released and it's still working fine running Linux 3.0. There's actually much higher chance that all of my hardware will die before Linux 3.4 comes out than that Linux developers will drop dri
      • by Jeremi ( 14640 )

        If I run Linux as a host and FreeBSD and Windows in kvm or VirtualBox, to whom have I given up my control too?

        The Chinese government, of course.

        (ducks)

    • Re:Linus is right (Score:4, Insightful)

      by MightyMartian ( 840721 ) on Friday August 19, 2011 @03:54PM (#37147270) Journal

      WTF? I've built three production Linux KVM servers now. Other than relying on the KVM team (backed mainly by Redhat), I'm not relying on anybody else. And if Redhat is a problem for you, then you've got bigger issues than the KVM virtualization modules in the kernel.

    • by Anrego ( 830717 ) *

      If you are talking virtualization in it's relationship to cloud computing, then I agree.

      Virtualization on your own hardware though... not much difference from the current state. It's just another (sometimes open source) piece of software we learn to trust (along with all the other software we use).

    • I am not following you?

      Virtualization is just taking your own Hardware and sharing some resources and partitioning others so you can run Multiple OS's on your hardware...

      It is not much more of a jump of putting your faith on the OS who will manage your hardware, and give you an interface level to the hardware.
      Virtualization you can think of it as a OS for your OS.

      The main value in Virtualization is from an Old computer science process... Keep you hardware running at high utilization doing something producti

      • I hope one day Linus or RMS states they like the taste of poo, just to see how many nuts out there will just blindly go along and do it because these guys have an opinion and because they have done or are doing great things they must be always right.

        It's a good thing you put that at the end, or most people would never read past it.

    • How do you figure? Maybe I'm just not the sharpest tool in the shed (nor have I ever claimed to be) but I really don't see much difference between trusting Intel/AMD/Motorola/etc. to be honest in what they put in the chipset and in trusting Citrix (Xen)/VMWare/KVM/whatever in what they put in the software. If anything, I probably have a better chance of detecting goofiness in FOSS software than I have in a chipset (not that I'm likely to detect anything in either one, but at least I *can* look at the sour
    • by dissy ( 172727 )

      The shift towards virtualization represents a further shift in control away from each person towards a reliance on the honest of others.

      And who exactly are you to tell me what I can and can not do with my own hardware?

      If I choose to run zero, one, or a hundred OSs on my virtualized hypervisor on the hardware I purchased, what right do you have to say it is a bad thing?

      If anything, you dictating that I shouldn't virtualize my own hardware because it is evil, is what would be taking control away from me. Virtualization gives me control. MUCH more control than the hardware itself can.

      And what are you going on about relying on the honesty of

  • Screws are evil (Score:5, Insightful)

    by Anonymous Coward on Friday August 19, 2011 @03:40PM (#37147078)

    Because I'm used to working with a hammer.

    Linus is not a god, just a guy, with his own prejudices.

    • Re:Screws are evil (Score:5, Insightful)

      by timeOday ( 582209 ) on Friday August 19, 2011 @05:15PM (#37148202)
      Read the article. Linus has accepted both KVM and Xen into the kernel, it talks about why he and some other guru think KVM was managed better and is a better implementation.

      Let's not confuse two completely different things: if Richard Stallman said something was "evil," it would mean he was morally opposed to it and wouldn't touch it with a 10 foot pole. But Linus calling hypervisor virtualization "evil" just means he'd rather work on hardware, but hey, you want virtualization, go ahead and take your pick of the ones Linux provides.

  • but its cheap in human resources since it is the ultimate reuse of code.

  • Good for beginners (Score:2, Interesting)

    by Anonymous Coward

    Virtualization is good for new junior programmers learning how to program firmware, sinceeany low level calls can not really destroy the real hardware, since protection can bee built right in.

    It's a crutch, but since we have a generation of programmers who can't do "the hard stuff" becuase "java does it for them", its certaintly good to have around.

  • Isn't Hardware _realization_? and/or if the hardware is virtualized then isn't it done with software? not "real hardware"? ...ok, i admit it, i'm lost. someone smarter than me, -you there-, some examples please. (which need not necessarily involve automobiles)
    • You go out and buy a Dell blade cluster, it contains 16 identical blades with 2 sockets of 6 cores each and 24 GB of RAM. You hook this blade cluster to an Equalogics array for storage. Install ESX on 15 servers, vcenter on 1, now you can install whatever servers you need, and they are entirely fault tolerant.

      Oops, there is smoke coming from one of the ESX systems, and it seems to be unresponsive; vCenter detects the failure and moves the virtual machines without downtime. I don't know what crack Linus i

  • VMware makes a hetrogenous environment far, far easier to deal with - we have some 70 odd servers running on 5 physical servers. It makes it much easier to single-task a given server/VM, spread the load without having to invest far more in server hardware, and allows having backup/redundant servers to allow for patching/upgrades of servers with much more minimal effort.

    While in-OS virtualization is great if you only require a single OS to do everything; but if you have hetrogenous servers to handle differen

    • by h4rr4r ( 612664 )

      Not at all. Put all the linux boxes in openvz or something like it and windows servers can go into their hypervisor until MS smartens up.

      Then you just need the linux boxes all on one set of hardware and windows on another. Vmware has other attractions, this is not really one of them.

      • Accept now you need a Linux Vitalization admin and a Windows Virtualization admin.. You have just doubled the number of "platform specific" gotchas you need to learn, plus unlike having a single VMWare cluster you now have two clusters, probably increasing your hardware cost per vm by needing both platforms to maintain a proper save resource overhead to handle failures.

    • by Locutus ( 9039 )
      but I remember a day when the corporate OS was capable of running finance, engineering, sales, and shipping all on the same box and with up times you could easily live with. Then along came Windows and it was like freak'n Tribbles because the OS failed so much they where putting one service on one box/OS. I've already seen virtualization getting praised at Windows shops because of how much hardware it can save. A side benefit is that now they can throw in a LAMP stack without asking and save some bucks bec
  • It's hard enough to get stuff to run reliably when you are dealing with real hardware.

    Adding another layer just increases the number of dark corners where bugs can hide.

    • I disagree. its a layer that *when properly done* reduces the complexity as the underlying hardware is totally masked, and you have to deal only with known virtual hardware.
      • by afidel ( 530433 )
        Bingo, when we upgraded from Nehalem's to Westmere CPU's we were able to do it without interrupting any running VM, we simply set the EVC mode for the cluster to Xeon Corei7 and we could move VM's back and forth between hosts with either generation of processor. We also move running VM's between storage arrays and even between local and SAN storage. We don't have to mess with storage drivers, network drivers, multipathing software, or any of that junk at the VM level so they are set it and forget it which a
    • That's not been my experience. In many respects virtualization simplifies things. Unless you're dealing with paravritualization, generally you're dealing with a much more "dumbed-down" environment; some limited number of emulated NICs, video cards, mass storage controllers, bus controllers and the like, and these are almost inevitably taken from widely-understood hardware. Yes, there could be bugs lying in wait within the virtualized drivers, but then again, it's not like real hardware has any lack of on

    • Hardware failures in our VMWare environment tend to go almost completely um-noticed by server admins and en users... We have had network cards fail, Host power loss, and ram failures... The VMWare brings the VMs back on line so fast that there is rarely an alarm on the service, instead just something we need to fix on the back-end.

      This goes extra for storage where we regularly shift VMs between SANs by different manufacturers using storage VMotion, LIVE.

  • by g00mbasv ( 2424710 ) on Friday August 19, 2011 @03:44PM (#37147128)
    The title is a bit on the FUD style. PROPER virtualization is not criticized by Linus, but improper implementation, namely cheap OS-level virtualization wich could lead to lazy shortcuts to patches and features implementation.
    • by LWATCDR ( 28044 ) on Friday August 19, 2011 @05:09PM (#37148142) Homepage Journal

      Man this and the reactions to it are dumb.
      "Ask the world's most famous kernel developer what he thinks of the virtualization wars going on the Linux community between KVM and Xen and you'll hear a condemnation (of a sort) of them both. "I'm not a virtualization kind of guy. I think virtualization is evil," Linus Torvalds told the crowd at LinuxCon on Wednesday during his keynote interview session with Greg Kroah-Hartman."
      Linus doesn't like using and probably really doesn't like dealing with this war.
      If you read more. ""I built a kernel because I wanted to get my hands grubby with things like I/O ports.""
      Really this headline is taken so out of context that it isn't funny. But it got people to flame on Slash and probably a lot of hits.

    • by Jonner ( 189691 )

      The title is a bit on the FUD style. PROPER virtualization is not criticized by Linus, but improper implementation, namely cheap OS-level virtualization wich could lead to lazy shortcuts to patches and features implementation.

      The article may be misleading, but it really seems like Linus really cares little for either KVM, which is more hardware-oriented, or Xen, which is more software-oriented. He has accepted both into Linux because they are good quality and many want them, but he doesn't personally care for either. I think it's odd that he used the word "evil" but I think he meant it purely tongue-in-cheek.

  • by Anonymous Coward

    It's actually Evil to not virtualize, because you waste electricity! It requires additional power for each physical server to run a single OS, plus the airconditioning costs for all those servers. This means your poluting the planet more by not virtualizing!

  • by stox ( 131684 ) on Friday August 19, 2011 @03:51PM (#37147214) Homepage

    If you want to see where virtualization is going, check out where VM370 was in 1977 or so. That is about as far as the current virtualization technology has gotten. Bare metal has its place, as does virtualization.

  • It's mostly true (Score:4, Interesting)

    by Mad Merlin ( 837387 ) on Friday August 19, 2011 @03:52PM (#37147220) Homepage

    Linus has never been diplomatic, but it's mostly true. A huge amount of virtualization done today involves the same host and guest OS, and in most of those cases, using something slimmer than full blown virtualization would make a whole lot more sense, even if only for the improved performance. One of the problems is familiarity, container type isolation isn't applicable to as many cases, so fewer people are familiar with it. One of the other problems is the perception that full virtualization is more secure (which is probably untrue).

    There is however, a large swath of problems that aren't solved well by container type isolation that virtualization does solve well. If you need to simulate different physical systems (with separate IP addresses), that's much easier with virtualization. Likewise if you need very different guest and host OSes, that's not a strong point of container type isolation. Also, if your guest OS is sensitive to hardware changes, virtualization makes a lot of sense. There's more, but you get the idea.

    • OpenVZ and Linux-VServer support separate IP addresses as very basic functionality. How do you suppose hosting providers create virtual private servers based on them if they don't? OpenVZ also supports private iptables per container, so that you can set up per-container firewalls. The main problem with containers is the staggering amount of ignorance about the subject.
  • by Anonymous Coward

    Having to reboot to play video games.

    • by tepples ( 727027 )
      @Anonymous Coward
      You don't need to reboot to play video games. You just need a Kazzo or a Retrode so that you can copy your 8- and 16-bit game cartridges into the computer and run them on an emulator.
  • by Anonymous Coward on Friday August 19, 2011 @03:56PM (#37147298)

    For those of you that look at FreeBSD jails, Linux OpenVZ, etc etc and say "but I want to migrate between servers!!!" there is an example of this being a possibility.

    http://www.7he.at/freebsd/vps/

    This guy did it with FreeBSD, but the real problem is that he needs funding to continue polishing it before it can ever be implemented into a FreeBSD release. I wish more people knew about this as we'd love to have it at work.

  • by BlueCoder ( 223005 ) on Friday August 19, 2011 @03:58PM (#37147316)

    The whole point of a modern OS is to virtualize the hardware so that each software application can play nice with each other.

    The hypervizor is the new ring 0. And it's going to evolve into a microkernel and user mode drivers. It's the new operating system and that what he should be working on if he likes hardware bits. The "Operating Systems" of old are evolving into plug in Operating Environments. It's the future, the revolution, get over it.

    • That's what I'm waiting for, one core OS at boot (specialized BIOS?) on top of which I can install several other OS' and switch between them with a keyboard shortcut.
      It would require a layer on top of graphic hardware first though.
    • by Jon Stone ( 1961380 ) on Friday August 19, 2011 @04:39PM (#37147820)

      Virtualisation is, in many ways, trying to do what the OS should already be doing, namely isolation between processes (though protected memory), providing an abstraction layer for the hardware (though drivers) and allocating resources (through the CPU/IO schedulers).

      Unfortunately, a certain OS has been so bad at doing this (historically) that people turn to virtualisation and you end up with a form of inner-platform effect [wikipedia.org]. We have Linux implementing the virtio drivers to interface with the hypervisor which implements real drivers to talk to the real hardware. We have the guest's scheduler trying to manage "virtual CPUs" without any real information about what resources are actually available. We have hypervisors trying [vmware.com] to re-implement copy-on-write [wikipedia.org] for memory pages that the OS already does out-of-the-box.

      Virtualisation is used as a "one size fits all" sledgehammer, often where it isn't the appropriate solution.

    • I thought that was exactly the difference between XEN and KVM. KVM uses the Linux kernel as ring 0, whereas XEN creates it's own 'sort of' kernel as ring 0.

      And, I don't think this approach is the best, because Linux and Unix still outperform any other approach by a long shot and have a lot of stability. So I prefer OpenVZ, Linux-Vserver.org and, since it is now the officially sanctioned solution: LXC. On the server side everything is Linux anyways. So why should I virtualize hardware, when I can use the per

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      The whole point of a modern OS is to virtualize the hardware so that each software application can play nice with each other.

      The hypervizor is the new ring 0. And it's going to evolve into a microkernel and user mode drivers. It's the new operating system and that what he should be working on if he likes hardware bits. The "Operating Systems" of old are evolving into plug in Operating Environments. It's the future, the revolution, get over it.

      The trend over the last decade to single task each OS instance, because they are hard to configure to support multiple applications. A single tasked operating system is still a HUGE, HUUUUGE amount of administrative overhead. The admin overhead involved with managing one ESX hypervisor running twenty discrete VM's is lower than one operating system (pick any one) running twenty discrete applications. Why is that?
      From ESX, we have programmatic, WUI, GUI, and CLI interfaces that can clone a live system, sn

  • by Kenja ( 541830 ) on Friday August 19, 2011 @04:00PM (#37147350)
    If not, then I'm going to stick with my virtual machines.
  • Linus Torvalds is... (Score:2, Interesting)

    by vranash ( 594439 )
    ... the John Carmack of Open Source *nix Kernels. Seriously, what has he personally done in the past 5 years other than fsck us with first Bitlocker and then Git, a decade long string of incompatible 2.6.x releases, and finally, in order to 'me too' bad judgements by other open source companies, releasing a half baked kernel as 3.0 that might as well have been called 2.7 or 2.8 for all the new features it provides. (That is to say... none?)
    • ... the John Carmack of Open Source *nix Kernels. Seriously, what has he personally done in the past 5 years other than fsck us with first Bitlocker and then Git, a decade long string of incompatible 2.6.x releases, and finally, in order to 'me too' bad judgements by other open source companies, releasing a half baked kernel as 3.0 that might as well have been called 2.7 or 2.8 for all the new features it provides. (That is to say... none?)

      I think that doing "a decade long string of [...] releases" in just 5 years is quite an accomplishment.

      (Ducks)

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Let's see, for starters Linus continues to effectively manage the evolution of the Linux kernel after 20 years - that in itself is an amazing accomplishment. Not only that, but he took a couple of months off to write git, which is an amazing distributed source code management system that is free for everybody to use. He's already accomplished more than most computer scientists accomplish in one lifetime, and Linus is in his early 40's.

    • by Bronster ( 13157 )

      He's personally responded to a couple of emails I've written to the list about issues, one a change that wasn't compatible with our usage and one an actual nasty corruption bug. In both cases he responded very quickly with a very precise description of what was going on, and took charge of making sure it got fixed (in one case guiding me to make a patch for the usage I needed)

      He's managed to keep a large project putting out regular releases and not regressing badly in any way. That's a bigger accomplishme

  • So now in the future of Slashdot, except a bunch of people praising Virtualization we are going to get a bunch of mindless sheep now condemning it.
    Much like how RMS got Slashdot to loose its love for Cloud computing.

  • Did anyone else hear Grandpa Simpson saying "Virtualization is evil I tells ya. EVIL!!!!" in their head while reading that?

    Perhaps I really am strange then.
  • by steveha ( 103154 ) on Friday August 19, 2011 @05:29PM (#37148338) Homepage

    Linus likes to say things that are a bit over-the-top. He trusts that his audience can detect the tongue-in-cheek nature of the comments.

    I do the same thing. If I say something like "I hate and fear Perl", I don't mean it literally.

    Some people were upset about Linus's presentation about Git where he bashed Subversion. I thought it was pretty clear that he was exaggerating his comments for comedic effects, and I was entertained rather than outraged.

    Linus does sometimes say things I disagree with. He resisted having an official kernel debugger for years, because he said kernel developers should be able to hold everything in their heads and not need a debugger to help them. (Did he ever give in on that?) But this current issue is a non-issue.

    steveha

  • He's just trying to sell more copies of his proprietary OS and hardware!
  • Virtualization is a stopgap measure, it helps work around the inadequacies of current operating systems by introducing a new layer of granularity and security.

    The purpose of an operating system is to share hardware in a secure and efficient manner. Unfortunately the security of systems is lacking, so you can never be sure of the side effects of installing or running an given application. Using a VM to allow damage to be rolled back is a hack to make the risks acceptable.

    If the operating systems did their jo

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