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Cloud Open Source

Xen 4.1 Hypervisor Released 105

Posted by Soulskill from the onward-and-upward dept.
LarsKurth writes "The Xen.org open source community just released a new version of the Xen Hypervisor, Xen 4.1. Feature highlights include a new prototype scheduler for latency-sensitive workloads, better support for very large systems (>255 CPUs, 1GB/2MB super page sizes), new security features, and many others. During the development cycle of Xen 4.1, the Xen community worked closely with upstream Linux projects to ensure that Xen dom0 support and Xen guest support are available from unmodified Linux distributions. The release announcement contains a full list of changes."
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Xen 4.1 Hypervisor Released More

Xen 4.1 Hypervisor Released

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  • Ever since IBM stopped contributing this Xen two years ago, the pace of Xen development has been pathetic. Not sure why this project is still alive.
    • Oracle is trying to enter the x86 virtualization market with Xen in a product called Oracle VM. I've used it, and it's ugly. Besides the PHB marketing tagling of "you can run Oracle on the entire stack!", I've seen no technical reasons to use it over KVM or VMWare in the enterprise.

      • But why not use its own Virtualbox [virtualbox.org]? I find it a lot more usable than Xen. Well, anything is easier to use than Xen.

        • VB's what I use here, and I like it fine myself. Just to be able to use windows on a linux box for certain things like embedded programming IDE's. Works well (after a small amount learning), lets my program PICS via USB, sound works, serial works, it all just works.

          Here's hoping Oracle doesn't start charging for it -- just after releasing some updates the mess up the free version. But you know they will, being Oracle and all. I suggest keeping older versions of the packages in case they do that. After

        • Re:Isn't Xen dead? (Score:5, Interesting)

          by fuzzyfuzzyfungus ( 1223518 ) on Friday March 25, 2011 @06:32PM (#35618076) Journal
          I'm pretty sure that Virtualbox and Xen are(in addition to architectural differences) aimed at substantially different uses of virtualization.

          Virtualbox, though there is nothing specifically stopping you from using it otherwise, is pretty much aimed at the "second and/or test OS on primary desktop" use case. Run whatever primary OS, run a small number of secondary OSes or virtual test boxes because RAM is cheaper than a rats nest of towers and KVM switches. This shows in the fairly simple configuration, easy support for peripheral-passthrough and graphical guest OS window, and lack of interest in things like automated guest migration.

          Xen, by contrast, is aimed much more at the "pool of VM servers supporting some large number of VM instances that are mostly there to interact over network only" style. Nothing prevents you from setting up your desktop as the dom0 OS, and using it like Virtualbox; but it would be a pain and not clearly beneficial. On the other hand, you get much more concern for large memory spaces, guest migration, and similar things.

          This isn't a precise analogy(since I suspect that they share somewhat more, just for cost reasons); but asking "Why use Xen when you could use Virtualbox?" is sort of like asking "Why use VMware ESX when you could use VMware Workstation?"
          • Also, I'd like to point out one stupid thing: VirtualBox won't let you allocate more than half of your physical memory to VMs. Even if you built the machine with excess of RAM so you could do just that... Want to run 2 1GB VMs in a 4GB machine with integrated (RAM stealing) video? can't do it, even if the machine isn't running anything but VMs.

          • Re: (Score:1)

            by g00ey ( 1494205 )
            Something, I'm really missing is a stronger "passthrough" implementation than Intel VT-d/AMD IOMMU that allows any hardware to be passed through to a guest OS / domU such that I can use Unix/Linux as Dom0 and play fully-fledged DirectX11 games on a multiway SLI/CrossFire on a Windows guest machine.

            I have the dream or vision that operating systems will grow into more simplistic hypervisors in the future. System environments that provide APIs such as .net or DirectX will shrink into wrappers that will pro

        • Virtualbox is their consumer x86 virtualization product, Oracle VM is their x86 enterprise virtualization solution; clusters, high-availability, etc.

          Think of it like this:

          Virtualbox = VMware Workstation
          Oracle VM = ESX/vSphere

      • Oracle is trying to ENTER the x86 virtualization market with Xen in a product called Oracle VM. I've used it, and it's ugly. Besides the PHB marketing tagling of "you can run Oracle on the entire stack!", I've seen no technical reasons to use it over KVM or VMWare in the enterprise.

        You keep using that word. I do not think it means what you think it means. http://www.virtualbox.org/ [virtualbox.org]

      • I've seen no technical reasons to use it over KVM or VMWare in the enterprise.

        Is anyone using KVM for server consolidation?

        KVM is a great tool for having a secondary VM on your desktop. In fact, one of the Xen developers who works remotely (and thus doesn't have the same access to a big farm of test hardware) actually uses KVM to do Xen development, when what he's working on doesn't require any hardware virtualization features. But if what you want is a dedicated VM-hosting box, Xen is the way to go.

        • Re: (Score:2)

          by h4rr4r ( 612664 )

          Lots of people do. KVM is what RHEL uses and pretty much everyone else as well. Xen is dead.

          • Ah, that was your prime opportunity to bring in actual examples. The lack thereof makes it clear to everyone that "Xen is dead" is just FUD.
          • Actually Xen is far from dead. Development is very active, and most of the important kernel-related patches have been upstreamed and included to Linux, including the much discussed Xen Dom0 support. So the situation nowadays is very different from a couple of years back.

    • Re: (Score:1)

      by Anonymous Coward

      Ever since IBM stopped contributing this Xen two years ago, the pace of Xen development has been pathetic. Not sure why this project is still alive.

      Amazon (arguably the biggest cloud service provider) uses Xen exclusively.

    • Re: (Score:3)

      by h4rr4r ( 612664 )

      Because they have not noticed that IBM abandoning them and KVM removing the need for them means they are dead. Give them time.

    • it was owned by xensource, now owned by citrix, really unlikely that IBM contributed more than the owners.
      Thanks playing FUD and toeing the party line on KVM

    • You have heard of Amazon EC2 right?
    • Maybe because it's the greatest virtualization technology for servers (see AWS, Openstack, and so on)? Because it's the virtualization of choice for cloud computing, with live migration working like a charm? Or because KVM doesn't offer the kind of functionality one may need, like being able to mount a partition directly in dom0 when you use LVM, and such kind of thing? Because it has great CPU schedulers, and lots of new things for nested virtualization which other products don't have? Or is it because oth
      • Great post! Many people don't seem to realize a lot has changed in the Xen-land during the last couple of years.. Xen dom0 support is now included in the upstream Linux kernel, and Xen developers are at the moment actively working on upstreaming for example qemu-xen to upstream Qemu. And for people who don't want to "do-it-yourself" there's Xen Cloud Platform (XCP) available.. opensource dedicated virtualization platform shipped as installable ISO image. http://xen.org/products/cloudxen.html [xen.org] .

    • You must've stopped looking a while ago. Admittedly it looked very grim a couple of years back when KVM hit the big time and Xen was stuck with their aging fork of 2.6.18 and not getting on well with the Linux kernel team.

      But it's different now - the last year or so seems to have been the busiest I've ever seen the Xen devel list and the pace still seems to be increasing. And I've been following along since 2.x or so about 6 or 7 years ago. Additionally the relationship with the Linux kernel upstream seems

    • Ref please? IBM has never been a major contributor to Xen, and Xen development, especially over the last year, has been just fine.

      The project is still alive because it is useful to thousands of organizations (including large corporations like Tesco, Bechtel, Fujitsu, SAP, cloud providers like Amazon and Rackspace, to name just a very few), and thus worth the time of various organizations (including Citrix, Oracle, AMD, Intel, and yes even RedHat) to pay developers to work on improving it.

      Are any major co

  • I run openSuse 11.2 which includes integrated support for hypervisor. When I attempted to implement it it required a kernel adjustment of some sort and a reboot. When I rebooted there was some issue with my screen configuration and x would not start up. I gave up and installed virtualbox instead which is freaking rad and worked flawlessly. Is there an advantage to xen that makes it worth the hassle?

    • Re: (Score:2)

      by Rennt ( 582550 )

      Xen isn't really for designed for desktops or workstations - VirtualBox's ease of use and integration extensions make it a clear winner in that area.

      But Xen is at home in datacenters/blade clusters/VPS hosting where kicks VMWare's ass.

    • Xen isn't a product for your desktop, on that side, it is both hard to use, and a pain. It integrates badly with DHCP, and almost never works with a WiFi card. That isn't why we love Xen. We love it on the server side. For your desktop, you did the right move when using Virtualbox.
  • XenServer, despite being pretty much the same product, is crap. Somehow, Citrix managed to ruin something that, at the time they bought it, ran well and was fairly solid. They changed enough to make it kludgy pile.

    • Re: (Score:2)

      by vux984 ( 928602 )

      So what is the best solution out there right now?

      I've got some vmware server stuff at home, and some Xen stuff at work, I wasn't happy with some of the vmware is doing, and if Xen is going down the crapper too...

      What is decent and getting better?

      • KVM seems to be the Next Big Thing. I don't have much experience with it. The last time I tried to get it up and running on a workstation using CentOS 5.something it failed miserably. I couldn't even get it running. It has reached much better maturity now, though. At least, I'm putting my faith in that statement seeing as Red Hat has phased Xen out and is moving all of their VM eggs into the KVM basket. I've been meaning to try it out again and see what I can do. I've heard anecdotal evidence that it is far

        • Re: (Score:1)

          by Jumpy ( 24568 )

          I've recently started using KVM as a desktop virtualization solution. On CentOS 5.5 and RHEL 6.0 Its pretty damn awesome imho. You can use virt-v2v to convert older VMs to newer VMs. Also can convert VMware VMs though I have not done that. I am using KVM to lean more about different Linux distros besides Red Hat. I have 4 VM's always running on my desktop at work (RHEL 6) as test boxes and I don't notice that much of a slowdown. I give a huge thumbs up to KVM. I have to use VMware at work but KVM is a bette

      • Re: (Score:2)

        by drsmithy ( 35869 )

        So what is the best solution out there right now?

        VMware. Nothing else comes close.

        It *is* expensive if you want all the cool stuff, though.

        • I know another guy who used to say that. I showed him VB (free) and he was amazed by it. Maybe you should check it out.

          • Re: (Score:3)

            by drsmithy ( 35869 )

            I know another guy who used to say that. I showed him VB (free) and he was amazed by it. Maybe you should check it out.

            I assume you mean VirtualBox. Virtualbox is an OS-hosted end user virtualisation application. It's not even playing the same game as bare metal hypervisors like and Xen and VMware ESX.

          • How do you do a server with virtual box, preferably with a minimum of command line (I like GUIs, even text based ones)?

            I tried virtual box and even used it for my mom's virtual machine so she could run her old windows programs (before VMware player could make VMs) and it worked nicely for that, but it never seemed to be server oriented for what I wanted to do (mail/dns/file servers).

            One thing I've never got working on VMware or Virtual Box on any version or platform is USB support. I must be doing something

            • I recently attended a conference hosted by VMWare. I spent a bit of time talking geek with one of the tech guys. Mostly we talked about vSphere's new *virtual* cisco switches. Anyway, the engineer said they have some support for some USB devices.

              That being said, I have never gotten USB to work in VB or VM Ware...

            • Re: (Score:2)

              by h4rr4r ( 612664 )

              How do you do a server with virtual box, preferably with a minimum of command line
              You don't belong near a server.

          • Re: (Score:2)

            by DarkOx ( 621550 )

            By cool stuff... the parent poster was likely talking about things like VMotion, DRS, hotsite replication and other stuff.

            Post back when Virtual Box can migrate a VM from one host to another hot without even dropping my SSH session.

      • I don't know what GP was talking about wrt XenServer. XenServer is a great piece of software, and getting better all the time; the free-as-in-beer version is very fully featured, missing only high-end features like automatic fail-over and disaster recovery. You can still create pools of VMs using shared storage, and there are no limits on the number of VMs, amount of memory, amount of virtual cpus, or anything like that. And if you prefer an "open" distribution, you can use the Xen Cloud Project [xen.org], which i

    • What makes XenServer crap? I think it's great, even the free version.
      • I find the free version to be better than the Citrix version. The problem I have with the Citrix version is that they took Xen and tried to reshape it into a VMware clone right down to the GUI used to manage it. In the process, they changed how things are managed on the command line and left holes in not only the documentation of those changes but also the functionality in the overall product. I think Citrix buying Xen was a step backward and if Xen had not been bought it probably would have advanced furthe
  • Obligatory XKCD [xkcd.com]

    • So, let me get this straight..

      You suggest that everyone should stop their work on anything that can be linked to linux in any way, until Adobe fixes their piece of crap?

  • Too much FUD. (Score:3)

    by PiSkyHi ( 1049584 ) on Friday March 25, 2011 @05:34PM (#35617578)
    14 Comments so far and no one seems to have read the Xen 4.1 wiki. Just to clarify, Xen and KVM are similar and you can use them for similar purposes. Xen 4.1 is aiming to be integrated into the native Kernel, it is very close already having some dom0 support now, native guest support as of 2.6.36 and will have full dom0 support soon. dom0 and domu kernels are now de-coupled, so things are going to become more generic which distributions will love.

    I tried and failed at Xen 4.0 after using Xen 3.x successfully sometime beforehand - I have been waiting for all those involved to update, stabilise and simplify Xen - looks like it is coming very soon.

    Redhat not using Xen for sometime now, fair enough, I'm not using Redhat so it won't bother me much.

    • Xen 4.1 is aiming to be integrated into the native Kernel, it is very close already having some dom0 support now, native guest support as of 2.6.36 and will have full dom0 support soon

      This is the crux of the matter, Xen has been going into the mainline kernel 'any day now' for the past 3 or 4 years. It's hard to believe that it took them until 2.6.36 (October 2010) to even get the domU support in there. Either Xen development proceeds at a snail's pace or the project is run by people who don't want to fit i

      • Re: (Score:2)

        by Eil ( 82413 )

        It's hard to believe that it took them until 2.6.36 (October 2010) to even get the domU support in there. Either Xen development proceeds at a snail's pace or the project is run by people who don't want to fit into the guidelines for code submitted to the kernel. Either way I can only see KVM running ahead in leaps and bounds while Xen struggles with getting into the kernel, and people struggle to get Xen installed.

        Xen was originally not accepted into the kernel because it was basically delivered as a huge

      • Re: (Score:1)

        by ijc ( 28677 )

        IIRC Xen 32 bit PV domU support was origianally added to mainline in the 2.6.22 or 23 release and 64 bit support was added in 2.6.27.The "native guest support as of 2.6.36" referred to in the parent was the addition of PV driver support (e.g. for disk and network devices) when running in a fully virtualised (AKA HVM) guest. Fully virtualised guests worked fine before then but with emulated devices.

      • Actually Xen dom0 support *IS* already in mainline upstream Linux kernel as of 2.6.37 ! Some xen backend drivers are still missing from upstream kernel, but upcoming Linux 2.6.39 includes xen-netback backend driver, and xen-blkback driver is planned for 2.6.40. http://blog.xen.org/index.php/2011/01/14/linux-2-6-37-first-upstream-linux-kernel-to-work-as-dom0/ [xen.org] The pvops framework was merged to Linux 2.6.24 a couple of years ago, and Xen pvops domU support was first usable in Linux 2.6.26. So Xen support

        • So some time early-mid 2012 we can expect to see proper dom0 support in the kernel, ie. you won't need a specially patched kernel to run a Xen server as you do today (even with 2.6.37)? This is good but still about 5 years after KVM entered the mainline kernel.

          • If you're using Xen 4.1.0 then 2.6.39-rc1 or newer as dom0 kernel will allow you to run VMs, since 2.6.39 includes xen-netback backend driver, and Xen 4.1 includes userspace/qemu-based blkback backend implementation. There's ongoing process to upstream the remaining bits.. based on earlier experiences upstreaming all at once clearly doesn't work, so it has to be done in small incremental steps :) Meanwhile there is 2.6.32 based long-term maintained tree with full dom0 support included available in xen.gi

  • If you want to run a ton of VMs on a server, Xen is great. It's fast and stable once you sort through the mess of getting a kernel that both supports your hardware and runs well as a Dom0 (the "host" machine).

    And for the past year or two, most distros have shipped kernels which would boot just fine "out of the box" on Xen virtual machines.

    It's what most "cloud" or VPS providers run (including Amazon, Rackspace, Slicehost, Linode, etc).

    However, if you're running a desktop and want to virtualize, Xen is proba

  • Yeah, so Xen has all these fancy features. So does KVM. So does VirtualBox. So does VMWare.

    The underlying features aren't really the important point - they haven't been for some time and that isn't going to change with this release. The important features right now are manageability - is there a pretty GUI to show the managers? A programmable, easily scriptable API? - and full feature-parity with the likes of VMWare. (Doesn't have to be parity with the enterprise versions, just parity with the free VM

    • I've been working for weeks toward setting up a test box for Xen (I want to learn it for work). In my research i found the webmin-related product cloudmin [webmin.com] which works for both Xen and KVM. Haven't tried it yet, hopefully it's as good as regularly webmin. That'd provide the GUI, not sure about the other stuff.

    • The underlying features aren't really the important point - they haven't been for some time and that isn't going to change with this release. The important features right now are manageability - is there a pretty GUI to show the managers? A programmable, easily scriptable API?

      Consider the Linux kernel from the criticisms you've just made. Does Linus's tree have important features for manageability? Does it have a pretty GUI to show managers? Is it programmable and easily scriptable? The answer is, of co

    • Xen online resizing of VM disks has been supported for a while already! You just need to use a kernel that supports it. Online resizing is supported in mainline upstream Linux as of 2.6.37 (iirc), and some distros have backported it older kernels.

      • So, what's the XM command to tell the guest that the disk size has changed?

        • No need to run XM commands, it's enough to resize the LVM volume in dom0, and domU will pick up the change automatically (assuming both dom0 and domU kernels have the online resize feature included).

          • Is this written down anywhere? I've been looking all over the place and all I can find is that there used to be a xm command to do it but it was removed.

            All I can find is discussion of resizing volumes offline. I want to resize a volume without restarting the domU.

            • Aha, at http://wiki.xensource.com/xenwiki/XenParavirtOps [xensource.com] I find:

              Features added in 2.6.36:
              Xen VBD (Virtual Block Device) online dynamic resize support for resizing guest disks (xvd*) on-the-fly.

            • It's mentioned on the Xen4.0 wiki page since that's when the feature was developed. http://wiki.xen.org/xenwiki/Xen4.0 [xen.org] . I think it was originally submitted by Novell developers, who wrote it for SLES11. Later Jeremy (pvops kernel maintainer) submitted it for upstream kernel inclusion, and it got included to upstream Linux in 2.6.36. It's also included in xen.git xen/stable-2.6.32.x branch. I've tested it myself, and all you need to do is to resize the LVM volume in dom0, and domU will detect the size chang

  • Does anyone actually use this?

    • Plenty of people, but mentioning it here is probably risky.

      If you're running predominatly Windows servers, it's the only way to go unless you want some of VMWares really advanced features, even then it's catching VMWare slowly.

      Personally I run ESXi at home since my home server doesn't have VT, and HV at work in a 6 node cluster.

    • Re: (Score:1)

      by gollito ( 980620 )
      Hyper-V is just.....wrong. Feature wise (and maybe just in in how the features are implemented) it doesn't compare to vmware. Take networking for example. In vmware it's easy as pie to setup VLAN's, VM only networks, etc. In Hyper-V it's a somewhat complicated process. The thin provisioning of hard drives by default is bad, bad, bad. Give me the option during VM build like vmware does.

  • I was sorta hoping this was about a new Vuzix competitor...

  • Don't believe the FUD in these party-line comments. I run a NetBSD Dom0 with now 7 Red Hat DomU's in an LDAP/messaging cluster on a single server, scoped to 10 concurrent VMs hitting iSCSI cluster targets.

    It's not a desktop product. It's designed for high-availability and dense clustering, has a mature codebase and tools, and it works well. And yes, Red Hat 6 runs just fine as a DomU out of the box, and can be a Dom0 as well, if you like (although not "supported" by Red Hat, still quite functional).

  • But does it finally support 24 and 32 bit color depth on the desktop? That was a huge stopping/stumbling block for me on integrating Zen into our datacenter. We ended up going with VMWare's ESXi because it's the only hypervisor that supports 24 bit color depth that I found. I would really have preferred Xen but they seem to have completely ignored the video memory segment of their product.

    Anyone know why this is? It seems like it would be a simple addition.

    • truecolor framebuffers have been supported for many years in Xen. You can install either PV or HVM VMs using truecolor graphics. In the case of PV domU you need to use 'vfb' or 'pvfb', aka paravirtual framebuffer. Framebuffers are exposed as VNC servers, or over SDL.

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