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[libvirt-users] migrating from XenServer / XCP to libvirt/KVM
by Daniel Pocock 15 Mar '17

15 Mar '17

I've been using XenServer / XCP (with the "xe" toolset) for a number of years for hosting servers used for development and free software projects and I'm now looking at migrating all those environments to libvirt / KVM. I had a look at the wiki[1] already and didn't see XenServer mentioned there. Could anybody help comment on or explain a few things: - comparison between XenServer and libvirt: I notice many similar concepts, for example, XenServer has storage repositories and libvirt has storage pools. However, in many examples such as this[2] it appears that libvirt requires more manual effort. For example, when you create a storage repository in XenServer, the tool takes a physical block device as input and creates the necessary volume group, logical volume and a filesystem. In that libvirt example, it appears each of those steps must be done manually. The networking examples are similar: the XenServer tools do all the Open vSwitch stuff behind the scenes but in the libvirt examples it appears necessary to create the bridge manually before telling libvirt about it. Is this all correct or are the examples I've seen out of date? Do more recent (or future) releases of libvirt aim to automate/hide more of these things? - what is best practice for virtual disk images? Does libvirt always use files (like XenServer) or can/should block devices be used directly? If using files, is any special care needed to avoid block alignment problems? - are there any guides or tools recommended for migrating small XenServer environments (less than 50 domains on a single physical node) to libvirt + KVM? - is there a list of small things that need to change in a VM before running it under libvirt / KVM? I'm guessing this might include bootloader config, updating the kernel, changing block device names in /etc/fstab and changing network device names in scripts - are there any others? - can anybody comment on more tricky issues that may arise in such a migration, for example, will a Windows VM be likely to run without modification when migrated from XenServer to libvirt/KVM or will it need extra drivers added or anything else before the migration? Regards, Daniel 1. http://wiki.libvirt.org/page/Main_Page 2. https://keepingitclassless.net/2014/01/libvirt-intro-basic-configuration/

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[libvirt-users] MIPS emulation broken - No PCI buses available
by Ian Pilcher 15 Mar '17

15 Mar '17

I am trying to create a QEMU MIPS guest, so that I can test some code for big-endian safety. Every attempt to create a MIPS guest is giving me an error: Unable to complete install: 'XML error: No PCI buses available' It seems like this is a known issue. https://www.redhat.com/archives/libvir-list/2016-May/msg00197.html However, I am still getting this on a fully updated Fedora 25 system with libvirt-2.2.0-2.fc25.x86_64. -- ======================================================================== Ian Pilcher arequipeno(a)gmail.com -------- "I grew up before Mark Zuckerberg invented friendship" -------- ========================================================================

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[libvirt-users] trouble after upgrading from 3.0.0 to 3.1.0
by Michael Ströder 15 Mar '17

15 Mar '17

HI! After the last OS update (openSUSE Tumbleweed) with libvirt being updated from 3.0.0 to 3.1.0 starting the VMs (qemu-kvm) does not work anymore: error: internal error: child reported: Kernel does not provide mount namespace: Permission denied Kernel was updated before to 4.10.1 and worked just fine with libvirt 3.0.0 packages. Any clue how to work around that? Ciao, Michael.

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Re: [libvirt-users] [libvirt] libvirt and dmesg
by Cedric Bosdonnat 15 Mar '17

15 Mar '17

Hello Pierre-Jacques, First note that you posted your message on the developer's mailing list. For such user questions, rather email: https://www.redhat.com/mailman/listinfo/libvirt-users According to https://linuxcontainers.org/lxc/manpages//man5/lxc.container.conf.5.html lxc.kmsg is only used to symlink /dev/kmsg to /dev/console. Thus setting this to 0 only results in the lack of that symlink. libvirt doesn't setup this link at all, may be it is coming from the lxc domain root file system. On Wed, 2017-03-15 at 08:49 +0100, Michel Pierre-Jacques wrote: > Hi all, il try to find the way to obtain the same use as in the > lxc config file lxc.kmsg=0 > > how to do that, with the xml of a lxc domain, i make lot of try without > success . > > is there another way to deny access to the dmesg for a libvirt lxc > domain ? >From what I see, dmesg doesn't necessarily requires /dev/kmsg (at least on opensuse). So blocking it may be more tricky. May be you should tell us more how you setup your container. -- Cedric

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[libvirt-users] question about libvirt and suspending guests during live migration
by Chris Friesen 13 Mar '17

13 Mar '17

Hi, I hope someone can help me out. I'm running into an issue with libvirt 1.2.12 reporting "operation failed: domain is no longer running" for a migration when qemu thinks it was fine. The steps are: 1) create guest with stress test running in it to dirty memory at a high rate (fast enough that it would not normally complete live-migration) 2) trigger live migration with dom.migrateToURI2() 3) while migration is in progress, call dom.suspend() on the migrating domain. What I see at this point is the following: a) At time 50.465 the monitoring code sees a VIR_DOMAIN_EVENT_SUSPENDED event, as expected. b) An instrumented qemu logs the following: 51.143: done transferring state 51.143: done migration 51.144: qmp_query_migrate reporting state completed c) At time 51.468 the monitoring code sees a VIR_DOMAIN_EVENT_RESUMED event, with detail of VIR_DOMAIN_EVENT_RESUMED_UNPAUSED c) At time 51.469 the the monitoring code sees a VIR_DOMAIN_EVENT_RESUMED event, with detail of VIR_DOMAIN_EVENT_RESUMED_MIGRATED e) At time 51.471 the dom.migrateToURI2() call raises an exception (this is python). The corresponding libvirt log file shows: "error : virNetClientProgramDispatchError:177 : operation failed: domain is no longer running" For what it's worth, the problem seems to be fixed in libvirt 1.2.17. In that version and later I don't see the VIR_DOMAIN_EVENT_RESUMED event, the migration just completes. I'm looking at the libvirt history, but I figured I'd ask here too... Thanks, Chris

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[libvirt-users] qemu-attach fails
by DS DS 09 Mar '17

09 Mar '17

Hi, I am using "qemu-attach" in virsh to attach to an existing qemu process so I can send monitor commands to it. the VM is started using qemu-kvm -net none -hda ./out.img -m 4G -nographic The VM gets started and the OS boots fine. Then, I start virsh and do a "qemu-attach 44273" which is the PID of the qemu process. virsh # qemu-attach 44273 error: Failed to attach to pid 44273 error: Cannot check QEMU binary qemu-kvm: No such file or directory qemu-kvm is in /usr/libexec. There is a symlink to it from /usr/bin and /bin. The virsh command "create" (for a different VM) works fine. What could be missing? Are there any debug/log messages/config files that can shed some light. Thanks.

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[libvirt-users] Help needed on a gentoo system after update to libvirtd 3.1.0
by Marko Weber | 8000 08 Mar '17

08 Mar '17

(sorry, dont know how i put my posting into an reply to an other issue before, new posting to sepearte it, big sorry) Hello list, i updated on a gentoo system from libvirtd 2.5 to 3.1.0 Now my windows machines cant access internet. I did a virbr1 with virt-manager and route it to the eth0, works fine on 2.5 Hello list, i updated on a gentoo system from libvirtd 2.5 to 3.1.0 Now my windows machines cant access internet. I did a virbr1 with virt-manager and route it to the eth0, works fine on 2.5 on install i get this: Important: The openrc libvirtd init script is now broken up into two separate services: libvirtd, that solely handles the daemon, and libvirt-guests, that takes care of clients during shutdown/restart of the host. In order to reenable client handling, edit /etc/conf.d/libvirt-guests and enable the service and start it: $ rc-update add libvirt-guests $ service libvirt-guests start For the basic networking support (bridged and routed networks) you don't need any extra software. For more complex network modes including but not limited to NATed network, you can enable the 'virt-network' USE flag. It will pull in required runtime dependencies If you are using dnsmasq on your system, you will have to configure /etc/dnsmasq.conf to enable the following settings: bind-interfaces interface or except-interface Otherwise you might have issues with your existing DNS server. For openrc users: Please use /etc/conf.d/libvirtd to control the '--listen' parameter for libvirtd. Use /etc/init.d/libvirt-guests to manage clients on restart/shutdown of the host. The default configuration will suspend and resume running kvm guests with 'managedsave'. This behavior can be changed under /etc/conf.d/libvirt-guests virt-manager starts fine and shows my vm´s. i dont touched /etc/dnsmasq cause i dont used it. so left untouched. yes, i added libvirt-guests with rc-update the virbr1 has 192.168.18.1 as address, and is reachable via ping from vm guest. but it cant resolve hostnames and cant ping ip´s outside the virtualisation host. anyone knows this effect after update? do i have to change some more things? or is this a bug? any help and hints are welcome thank you marko weber on install i get this: Important: The openrc libvirtd init script is now broken up into two separate services: libvirtd, that solely handles the daemon, and libvirt-guests, that takes care of clients during shutdown/restart of the host. In order to reenable client handling, edit /etc/conf.d/libvirt-guests and enable the service and start it: $ rc-update add libvirt-guests $ service libvirt-guests start For the basic networking support (bridged and routed networks) you don't need any extra software. For more complex network modes including but not limited to NATed network, you can enable the 'virt-network' USE flag. It will pull in required runtime dependencies If you are using dnsmasq on your system, you will have to configure /etc/dnsmasq.conf to enable the following settings: bind-interfaces interface or except-interface Otherwise you might have issues with your existing DNS server. For openrc users: Please use /etc/conf.d/libvirtd to control the '--listen' parameter for libvirtd. Use /etc/init.d/libvirt-guests to manage clients on restart/shutdown of the host. The default configuration will suspend and resume running kvm guests with 'managedsave'. This behavior can be changed under /etc/conf.d/libvirt-guests virt-manager starts fine and shows my vm´s. i dont touched /etc/dnsmasq cause i dont used it. so left untouched. yes, i added libvirt-guests with rc-update the virbr1 has 192.168.18.1 as address, and is reachable via ping from vm guest. but it cant resolve hostnames and cant ping ip´s outside the virtualisation host. anyone knows this effect after update? do i have to change some more things? or is this a bug? any help and hints are welcome thank you marko weber -- zbfmail - Mittendrin statt nur Datei! OpenDKIM, SPF, DSPAM, Greylisting, POSTSCREEN, AMAVIS, Mailgateways Mailfiltering, SMTP Service, Spam Abwehr, MX-Backup, Mailserver Backup Redundante Mailgateways, HA Mailserver, Secure Mailserver

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[libvirt-users] events dispatching in synchronous mode
by Matczak, KrzysztofX 08 Mar '17

08 Mar '17

Hi Is there any way to get events dispatching in synchronous mode ? I mean I'm running my own events polling loop which calls virEventRunDefaultImpl each turn . I'd expect to get my callback function called synchronously , but it's not . Seems that's async call. Maybe it's my general misunderstanding and I shouldn't use virEventRunDefaultImpl for that ? Thanks in advance for any guidance Krzysztof -------------------------------------------------------------- Intel Research and Development Ireland Limited Registered in Ireland Registered Office: Collinstown Industrial Park, Leixlip, County Kildare Registered Number: 308263 This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.

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[libvirt-users] Cache / IO Setting for qcow2 disks with prealloc=metadata?
by Marko Weber | 8000 08 Mar '17

08 Mar '17

Hello, i´ve done 2 vm with qcow2 disks and created them with qemu-img with prealloc=metadata. Virt-Manager shows me under the performance settings for the Storage, Cache= Hypervisor Default IO= Hypervisor Default Is this the best setting? Or do i choose "native" IO on prealloc=metadata created disks? And do i have to change Cache too? The Virtualisation Host is gento linux, the qcow2 files are stored on a xfs partition, qemu is build with "xfs" Flag. thanks for hints and tipps marko -- zbfmail - Mittendrin statt nur Datei! OpenDKIM, SPF, DSPAM, Greylisting, POSTSCREEN, AMAVIS, Mailgateways Mailfiltering, SMTP Service, Spam Abwehr, MX-Backup, Mailserver Backup Redundante Mailgateways, HA Mailserver, Secure Mailserver

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Re: [libvirt-users] Compile DLL for Windows
by Kartik Vaishnav 08 Mar '17

08 Mar '17

I would like to know if there is a proper documentation for compiling libvirt for Windows. This is in regard to the latest versions of libvirt. Also, most answers are outdated and the scripts by Matthias Bolte on github don't use the latest versions and patches for libvirt. Regards, Kartik Vaishnav

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