xen December 2007

xen@lists.fedoraproject.org

42 participants
36 discussions

Update to Xen 3.1.2 available for testing
by Daniel P. Berrange 07 Dec '07

07 Dec '07

FYI, in both Fedora 7 & and Fedora 8, I have got new updates of the Xen userspace to be sync to the latest Xen 3.1.2 bugfix release available for testing. If you wish to test this, you can do yum --enablerepo=updates-testing update xen If there are no major problems reported I will push these to 'updates' in about a week. Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

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fedora 8 : exit a windows VM
by nooroon 07 Dec '07

07 Dec '07

Hi, I'm testing a fedora 8 and it was a good surprise for me : virtualization tools are more usable, and virtualization with xen seems more stable. I'm using xen to create a windows xp VM. the only issue that I have, is when i ask windows to stop the machine, with traditionnal windows tools : start>shutdown computer the windows OS is stopping but the VM doesn't stop. It hangs on a windows screen that says "you can now safely stop the computer". With xen and fedora 7, I didn't have this issue. Does anyone have an explanation?

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Problem booting Fedora 8 guest on FC6 host
by Robin Bowes 06 Dec '07

06 Dec '07

Hi, I'm trying to get a Fedora 8 para-virtual guest to run on a FC6 host. I had problems with the install because of the bugs in the 0.200 release of virtinst. I fixed this by doing a source install of virtinst-0.300. The F8 install completed succesfully, but when the guest boots I get this msg: <snip initial boot msgs> md: Autodetecting RAID arrays. md: autorun ... md: ... autorun DONE. VFS: Cannot open root device "vg_skeggles/lv_root" or unknown-block(0,0) Please append a correct "root=" boot option Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) Has anyone got any ideas about how to fix this? I am currently using kernel-xen-2.6.20-1.2952.fc6 and xen 3.0.3-9.fc6 (I've upgraded to kernel-xen-2.6.20-1.3002.fc6 and xen-3.0.3-13.fc6 but not rebooted yet). My xen config file (created automatically by virt-install) is as follows: name = "skeggles" uuid = "a8912edd-ea7c-f324-f1bb-fdbc0c1a4b65" maxmem = 512 memory = 512 vcpus = 1 bootloader = "/usr/bin/pygrub" on_poweroff = "destroy" on_reboot = "restart" on_crash = "restart" sdl = 0 vnc = 0 vncunused = 0 disk = [ "phy:/dev/vg_guests/lv_skeggles,xvda,w" ] vif = [ "mac=00:16:3e:4c:82:c7,bridge=xenbr0" ] Thanks, R.

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recompile for using sdl and vnc
by nooroon 05 Dec '07

05 Dec '07

Hello, I'm using fedora 7 with xen 3.1 from binaries rpm. I try to use the sdl display, but when i configure my VM with *<graphics type='sdl'/> * no window pops up. Thanks to goolgle, I've found someone how got the same issue, and it seems that qemu-dm was not compile whith sdl support. What is the best way to recompile qemu-dm whith sdl support? In fact, I'd like to have sdl for local display of my VM, and vnc for remote access to it. What configuration should I use to do so? Thanks

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Guest Image File Size
by Aaron Metzger 04 Dec '07

04 Dec '07

virt-install has a checkbox which suggests that you can avoid preallocating the entire guest image size -- that the guest image file will grow on demand. Does this work for Xen or is it only supported for KVM and the QEMU COW files? My experience when creating Xen guests as regular files is that I end up with a file that is the full size even when I pick the option to not preallocate the entire image. -- Thanks, Aaron

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Xen : virsh error
by unixfoo 04 Dec '07

04 Dec '07

Greetings, When I try to use "virsh", I get the below error. ( xm list returns details though ). I use Fedora 8 and xen. [root@un1xf00 ~]# virsh virsh: error: failed to connect to the hypervisor [root@un1xf00 ~]# xm list Name ID Mem VCPUs State Time(s) Domain-0 0 4885 4 r----- 399430.4 webhttp10000 11 2048 2 -b---- 65141.6 webhttp10001 18 2560 2 -b---- 358.0 webhttp10002 14 2048 2 -b---- 81720.5 [root@un1xf00 ~]# Any configuration to be done for virsh. Please help -unixfoo http://unixfoo.blogspot.com

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Best practices questions
by Lopez, Denise 03 Dec '07

03 Dec '07

Hi all, I am in the process of building a new Xen server from scratch and wanted to ask a couple of questions about best practices. First, should the guest domains be image files or LVM's or just regular ext3 partitions? What are the pros and/or cons of each? Second, since the Dom0 is supposed to be kept secure, and most of my servers I don't install any X11 server on, is there any security risk installing an X11 server on the Dom0 in order to take advantage of the virt-manager GUI interface? Thank you in advance for any thoughts and or opinions. Denise Lopez UCLA - Center for Digital Humanities Network Services Linux Systems Engineer 337 Charles E. Young Drive East PPB 1020 Los Angeles, CA 90095-1499 310/206-8216

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lv as "partition"?
by Maximilian Freisinger 01 Dec '07

01 Dec '07

Hello, im just trying to use a logical volume as a partition (for example sdc1) in my domU. As there seems to be no possibility to define such things on virt manager, i tried virsh with attach-disk and attach-device. But i always get: libvir: Xen Daemon Fehler: POST Operation schlug fehl. (Xend.err 'Device 2081 not connected') my xml for device: my definition for disk: virsh attach-disk /dev/master/part01 sdc1 my question is where is my error, or how can i achieve my aim? thx _________________________________________________________________ You keep typing, we keep giving. Download Messenger and join the i’m Initiative now. http://im.live.com/messenger/im/home/?source=TAGLM

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Re: [Fedora-xen] Fedora Core 8 + Xenbr0 + network bridging?
by Christian Lahti 01 Dec '07

01 Dec '07

Hi Dale: I work with David who posted the original question to the mailing list. I think we need to give a bit more background info on what we are trying to do. We are running a mixed environment of mostly CentOS 3, 4and 5, we do have a few windows servers and XP systems as well. We are looking to virtualize all these platforms. Normally we have a bonded pair of NICs for the physical hosts, we were able to get this running using CentOS 5 x86_64 with no problems, the guest machines use the bonded pair in bridged mode as expected after a bit of tweaking. The biggest issue we found with EL5 is that windows guest performace is dismal at best, hence our decision to have a look at Fedora Core 8 x86_64. I am happy to report that performance for all of our guest platforms is *very* good with FC8, but it seems that libvirt changed the way networking is setup for Xen. The default NAT configuration is pretty useless for production server environment. Thanks to the mailing list we are now able to bridge a single NIC on FC8 (like eth0 for example), but we cannot figure out how to get a bridge for bond0 (comprised of eth0 and eth1) defined and available to Xen. All the tweaks that worked find on EL5 have not worked so far on FC8. I am going to review your document tomorrow and give it a try, but any idea on whether your methodology will work on FC8 and libvirt? I am willing to blow a Sunday to get this worked out once and for all :) Basically we are after good performance on both para and fully virtualized guests using a bonded pair of GB NICs for speed and redundancy. If this can be achieved with enterprise linux then that would be preferable, but we will go FC8 if the bonding thing can be sorted out. By the way Xensource 4.x looks to be a respin of RHEL5 and has pretty good performance but their free version is limited to 32bit (and hence 4GB ram). Adding the clustering failover is the next step of course :) Thanks again for the help so far. /Christian >>>>>>>>>>> just FYI for the list, I have a how-to for a bonded and VLAN tagged network. http://www.certifried.com ODT and PDF formats available. It might not be the best way, but I've sent it out to my colleagues several times and have never received any negative feedback. Mark Dale Bewley wrote: I haven't done bonding, but you should be able to bond them and then compose a bridge on top of this bonded device I would think. -- Dale Bewley - Unix Administrator - Shields Library - UC Davis GPG: 0xB098A0F3 0D5A 9AEB 43F4 F84C 7EFD 1753 064D 2583 B098 A0F3 -- Fedora-xen mailing list Fedora-xen redhat com https://www.redhat.com/mailman/listinfo/fedora-xen **************************************************************************** Checked by MailWasher server (www.Firetrust.com) WARNING. No FirstAlert account found. To reduce spam further activate FirstAlert. This message can be removed by purchasing a FirstAlert Account. ****************************************************************************

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FYI: The plan for Xen kernels in Fedora 9
by Daniel P. Berrange 01 Dec '07

01 Dec '07

This is a friendly alert of the major plans we have for Xen kernels in Fedora 9 timeframe... Since we first added Xen in Fedora Core 5, our kernels have been based on a forward-port of XenSource's upstream Xen kernels, to new LKML. For a long time we ported their 2.6.16 tree to 2.6.18. Now we do ports of their 2.6.18 tree to 2.6.21/22/23, etc. At the same time, upstream Linux gained Xen support for i386 DomU, and shortly x86_64 DomU, and is generally getting ever more virtualization capabilities. As everyone knows, we have tended to lag behind Fedora's state-of-the-art bare metal kernels by several releases due to the effort required to port Xen to newer LKML releases. Despite our best efforts, this lag has been getting worse, not better. We have taken the decision, that this situation is unacceptable for Fedora 9. We simply cannot spend more time forward porting Xen kernels. Either Xen has to be dropped entirely, or we need a different strategy for dealing with the kernels. Since people seeem to use Xen, we have decided not to drop it :-) So the plan is to re-focus 100% of all Xen kernel efforts onto paravirt_ops. LKML already has i386 pv_ops + Xen DomU. We intend to build on this to add: - x64_64 pv_ops - x86_64 Xen DomU on pv_ops - i386 & x86_64 Xen Dom0 on pv_ops - memory balloon - paravirt framebuffer - save/restore All of this based on same LKML release as Fedora bare metal. If all goes to plan it may even be in the base kernel RPM, instead of kernel-xen, but thats a minor concern compared to the actual coding. Getting all this done for Fedora 9 is seriously ambitious, but it is the only long term sustainable option, other than dropping Xen entirely. What this means though, is that Fedora 9 Xen will certainly be going through periods of instability and will certainly be even buggier than normal. F9 may well end up lacking features compared to Xen in Fedora 8 & earlier (eg no PCI device passthrough, or CPU hotplug). On the plus side though we will be 100% back in sync with bare metal kernel versions & hopefully even have a lot of this stuff merged in LKML to make ongoing maintainence sustainable. Short term pain; Long term gain! I have not got any ETA on when any of these kernel changes will appear in rawhide - some time before the F9 feature freeze date is best guesstimate. We will alert people when the time comes. There is a F9 feature page with some amount of info about the plan... http://fedoraproject.org/wiki/Features/XenPvops In terms of Fedora 6/7/8 maintainence... The kernel-xen in these existing releases already lags behind the bare metal kernel version by 2-3 releases. We do not intend to continue trying to rebase the kernel-xen in existing Fedora releases. It will be essentially important bug-fix mode only. This is neccessary to enable maximum resources to be focused on the critical Fedora 9 Xen work. Regards, Dan ...on behalf of some very busy Fedora Xen kernel developers :-) -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|

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Fedora Core 8 + Xenbr0 + network bridging?
by David Levinger 30 Nov '07

30 Nov '07

Hello all, I was working with Xen and Cent OS and by default a virtual networking driver called Xenbr0 was created that acted as a "pass through" for the virtual machine. IE that machine contacted our real DHCP server and requested an IP address and all was well. However, on Fedora Core 8 it seems that the default networking setup is to use virbr0 and to have a totally different subnet and the host machine assigning IP addresses to the guests... How can I get back to just a pure network bridge that had the guests contact our DHCP server for leases? Thanks! David **************************************************************************** Checked by MailWasher server (www.Firetrust.com) WARNING. No FirstAlert account found. To reduce spam further activate FirstAlert. This message can be removed by purchasing a FirstAlert Account. ****************************************************************************

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xen December 2007