- Users - libvirt List Archives

Re: [libvirt-users] Fwd: kvm
by Stefan Hajnoczi 23 Apr '13

23 Apr '13

On Mon, Apr 22, 2013 at 10:59:25AM +0100, Gary Lloyd wrote: > I was wondering if anyone could help me with an issue with KVM and ISCSI. > > If we restart a controller on our EqualLogic SAN or there are any > network interruptions on the storage network, KVM guests throw a > wobbler and their files systems go into read only(centos 5.9 guest > with virtio driver). > > I have read a few forums that indicate you can set disk timeout values > on the guests themselves but this is not possible using the virtio > driver, which is what we are currently using. > > Is there any way we can instruct KVM to pause the vm's if there is a > storage failure and resume them when the storage comes back online ? > > We are currently running Centos 6.4. There seems to be a werror='stop' > and rerror='stop' options to achieve this but if I try to put these in > options in the libvirt xml file for a vm, libvirt appears to be > removing them. Please email libvirt-users(a)redhat.com for questions about libvirt in the future. This is a question about libvirt domain XML. The documentation is here: http://libvirt.org/formatdomain.html#elementsDisks The attribute is called "error_policy". The documentation says: The optional error_policy attribute controls how the hypervisor will behave on a disk read or write error, possible values are "stop", "report", "ignore", and "enospace".Since 0.8.0, "report" since 0.9.7 The default setting of error_policy is "report". There is also an optional rerror_policy that controls behavior for read errors only. Since 0.9.7. If no rerror_policy is given, error_policy is used for both read and write errors. If rerror_policy is given, it overrides the error_policy for read errors. Also note that "enospace" is not a valid policy for read errors, so if error_policy is set to "enospace" and no rerror_policy is given, the read error policy will be left at its default, which is "report". Stefan

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[libvirt-users] Libvirt profiling
by Jon Martin Sigvaldsen 23 Apr '13

23 Apr '13

Hi For a school project I am researching performance issues when using libvirt to run very large numbers of virtual machines. My experiments indicate that having more CPU cores negatively impacts the performance. A simple desktop with an Intel Core 2 Duo E6550 performs better than a server with a 48 core AMD CPU. Limiting the cores used through 'cputune' improves performance on the server. If anyone has got any explanations for this, it would be greatly appreciated. Further on I would like to profile the slowdowns, but I am not sure how to approach this problem. Any recommendations on how to do this? Best regards Jon

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[libvirt-users] Sanlock - what are my options?
by Russell Jones 23 Apr '13

23 Apr '13

Hi all, I have an RHCS 2 node cluster utilizing SAN storage with GFS2 for the VM images. I am looking into configuring Sanlock, however am running into some architecture questions with it. The documentation for Sanlock states: "The sanlock plugin needs to create leases in a directory that is on a filesystem shared between all hosts running virtual machines. Obvious choices for this include NFS or GFS2." I do not have a highly available NFS mount where I can store the disk leases, and I cannot store the lockspace on the same GFS2 mount as the disk images as during fencing/journal recovery disk I/O can become blocked, which causes Sanlock to log warnings/errors about renewals. Is there another option for configuration?

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[libvirt-users] problem when get the vm cpu stat
by Wangkai (Kevin,C) 20 Apr '13

20 Apr '13

Hi all, I try to get vm cpu stat by function "virDomainGetCPUStats", when the vm Cpu usage is 100%, I can see from the vm shell by "top", when the info Get by the "virDomainGetCPUStats" show only the "cpu_time" increased, "user_time" and "system_time" was not changed at all. Is that correct ? How can I get the vm cpu usage? nparams = virDomainGetCPUStats(domain, NULL, 0, -1, 1, 0); virDomainGetCPUStats(domain, params, nparams, -1, 1, 0); Thanks, Kevin.

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[libvirt-users] Unexplained shutdown of VM on upgrade of libvirt package
by Chandana De Silva 19 Apr '13

19 Apr '13

I am running KVM on Centos 6.3 and am seeing an unexplained shut down of two guests. The libvirt package was upgraded to libvirt-0.10.2-18.el6_4.4.x86_64 at the time of the shutdown. Only the two guests shown below was affected, while 9 others running on the same hypervisor were not. Can some one help me to find the cause please ? Regards Chandana GUEST #1 ======== 2013-04-10 04:15:02.903+0000: starting up LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name guinness-a -S -M rhel6.3.0 -enable-kvm -m 4471 -smp 2,sockets=2,cores=1,threads=1 -uuid 894072ba-634c-40a2-9f70-0338d124abc3 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/guinness-a.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/libvirt/images/guinness-a.img,if=none,id=drive-ide0-0-0,format=raw -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -netdev tap,fd=28,id=hostnet0 -device e1000,netdev=hostnet0,id=net0,mac=54:52:00:98:7f:cc,bus=pci.0,addr=0x3 -netdev tap,fd=33,id=hostnet1 -device e1000,netdev=hostnet1,id=net1,mac=54:52:00:c4:d4:fd,bus=pci.0,addr=0x5 -netdev tap,fd=34,id=hostnet2 -device e1000,netdev=hostnet2,id=net2,mac=54:52:00:a3:33:24,bus=pci.0,addr=0x6 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc 127.0.0.1:1 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 char device redirected to /dev/pts/11 2013-04-19 01:31:23.502+0000: shutting down qemu: terminating on signal 15 from pid 12852 GUEST #2 ======== 2013-03-24 22:30:36.881+0000: starting up LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name singha-a -S -M rhel6.3.0 -enable-kvm -m 2048 -smp 2,sockets=2,cores=1,threads=1 -uuid 52761f28-8f8d-4d79-a9c0-fd5222502cf4 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/singha-a.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/libvirt/images/singha-a.img,if=none,id=drive-ide0-0-0,format=raw -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -netdev tap,fd=32,id=hostnet0 -device e1000,netdev=hostnet0,id=net0,mac=54:52:00:2c:75:26,bus=pci.0,addr=0x3 -netdev tap,fd=33,id=hostnet1 -device e1000,netdev=hostnet1,id=net1,mac=54:52:00:b3:80:dd,bus=pci.0,addr=0x5 -netdev tap,fd=34,id=hostnet2 -device e1000,netdev=hostnet2,id=net2,mac=54:52:00:e6:aa:a2,bus=pci.0,addr=0x6 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc 127.0.0.1:0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 char device redirected to /dev/pts/5 2013-04-19 01:31:23.515+0000: shutting down qemu: terminating on signal 15 from pid 12852 PID 12582 is the libvirtd daemon, and I see this in the libvirtd log: 2013-04-19 01:31:23.492+0000: 13039: info : libvirt version: 0.10.2, package: 18.el6_4.4 (CentOS BuildSystem <http://bugs.centos.org>, 2013-04-18-16:13:45, c6b7.bsys.dev.centos.org) 2013-04-19 01:31:23.492+0000: 13039: error : virSecuritySELinuxReserveSecurityLabel:676 : internal error MCS level for existing domain label already reserved 2013-04-19 01:31:23.515+0000: 13035: error : virSecuritySELinuxReserveSecurityLabel:676 : internal error MCS level for existing domain label already reserved

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[libvirt-users] How can I define a network using an exist host bridge
by Wangkai (Kevin,C) 18 Apr '13

18 Apr '13

Hi all, When I defined a network use the host bridge "virbr1" an error occurred : "libvir: error : Unable to create bridge virbr1: File exists" But how can I define this network use the host bridge "virbr1" ? <network> <name>def1</name> <bridge name='virbr1'/> <forward mode='nat'> <interface dev='eth0'/> </forward> </network> Thanks, Kevin

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[libvirt-users] libvirt 1.0.3 Vs 1.0.4 / cgroup devices
by Mohamed Larabi 18 Apr '13

18 Apr '13

Hi there, I am using libvirt with lxc to create fedora 16 & 18 containers on fedora 18 host. first I did the setup with libvirt 1.0.3 and everything worked fine, then after upgrading to libvirt 1.0.4, I could not create character device on the guests : Test on the guest1 : # ls -l /dev total 0 lrwxrwxrwx. 1 root root 10 Apr 17 21:18 console -> /dev/pts/0 lrwxrwxrwx. 1 root root 11 Apr 17 21:18 core -> /proc/kcore lrwxrwxrwx. 1 root root 13 Apr 17 21:18 fd -> /proc/self/fd crw-rw-rw-. 1 root root 1, 7 Apr 17 21:18 full drwxr-xr-x. 2 root root 0 Apr 17 21:18 hugepages prw-------. 1 root root 0 Apr 17 21:18 initctl srw-rw-rw-. 1 root root 0 Apr 17 21:18 log drwxrwxrwt. 2 root root 40 Apr 17 21:18 mqueue crw-rw-rw-. 1 root root 1, 3 Apr 17 21:18 null crw-rw-rw-. 1 root root 5, 2 Apr 18 10:31 ptmx drwxr-xr-x. 2 root root 0 Apr 17 21:18 pts crw-r--r--. 1 root root 1, 8 Apr 17 21:19 random drwxrwxrwt. 2 root root 40 Apr 17 21:18 shm lrwxrwxrwx. 1 root root 15 Apr 17 21:18 stderr -> /proc/self/fd/2 lrwxrwxrwx. 1 root root 15 Apr 17 21:18 stdin -> /proc/self/fd/0 lrwxrwxrwx. 1 root root 15 Apr 17 21:18 stdout -> /proc/self/fd/1 lrwxrwxrwx. 1 root root 10 Apr 17 21:18 tty1 -> /dev/pts/0 crw-rw-rw-. 1 root root 1, 9 Apr 17 21:18 urandom crw-rw-rw-. 1 root root 1, 5 Apr 17 21:18 zero # rm -f /dev/random (successful) # mknod random c 1 8 mknod: `random': Operation not permitted Config on the host : knowing that selinux is set to permissive and c 1:8 rwm is in the cgroup devices list of the guest1 # cat /sys/fs/cgroup/devices/ libvirt/lxc/guest1/devices. list c 1:3 rwm c 1:5 rwm c 1:7 rwm c 1:8 rwm c 1:9 rwm c 5:0 rwm c 5:2 rwm c 10:229 rwm c 136:* rwm is this a change that was introduced intentially on 1.0.4 ? if yes, how can I make it work ? please advice Thank you in advance Mohamed

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[libvirt-users] libvirt 1.0.3 Vs 1.0.4 / cgroup devices
by mohamed amine Larabi 18 Apr '13

18 Apr '13

Hi there, I am using libvirt with lxc to create fedora 16 & 18 containers on fedora 18 host. first I did the setup with libvirt 1.0.3 and everything worked fine, then after upgrading to libvirt 1.0.4, I could not create character device on the guests : Test on the guest1 : # ls -l /dev total 0 lrwxrwxrwx. 1 root root 10 Apr 17 21:18 console -> /dev/pts/0 lrwxrwxrwx. 1 root root 11 Apr 17 21:18 core -> /proc/kcore lrwxrwxrwx. 1 root root 13 Apr 17 21:18 fd -> /proc/self/fd crw-rw-rw-. 1 root root 1, 7 Apr 17 21:18 full drwxr-xr-x. 2 root root 0 Apr 17 21:18 hugepages prw-------. 1 root root 0 Apr 17 21:18 initctl srw-rw-rw-. 1 root root 0 Apr 17 21:18 log drwxrwxrwt. 2 root root 40 Apr 17 21:18 mqueue crw-rw-rw-. 1 root root 1, 3 Apr 17 21:18 null crw-rw-rw-. 1 root root 5, 2 Apr 18 10:31 ptmx drwxr-xr-x. 2 root root 0 Apr 17 21:18 pts crw-r--r--. 1 root root 1, 8 Apr 17 21:19 random drwxrwxrwt. 2 root root 40 Apr 17 21:18 shm lrwxrwxrwx. 1 root root 15 Apr 17 21:18 stderr -> /proc/self/fd/2 lrwxrwxrwx. 1 root root 15 Apr 17 21:18 stdin -> /proc/self/fd/0 lrwxrwxrwx. 1 root root 15 Apr 17 21:18 stdout -> /proc/self/fd/1 lrwxrwxrwx. 1 root root 10 Apr 17 21:18 tty1 -> /dev/pts/0 crw-rw-rw-. 1 root root 1, 9 Apr 17 21:18 urandom crw-rw-rw-. 1 root root 1, 5 Apr 17 21:18 zero # rm -f /dev/random (successful) # mknod random c 1 8 mknod: `random': Operation not permitted Config on the host : knowing that selinux is set to permissive and c 1:8 rwm is in the cgroup devices list of the guest1 # cat /sys/fs/cgroup/devices/libvirt/lxc/guest1/devices.list c 1:3 rwm c 1:5 rwm c 1:7 rwm c 1:8 rwm c 1:9 rwm c 5:0 rwm c 5:2 rwm c 10:229 rwm c 136:* rwm is this a change that was introduced intentially on 1.0.4 ? if yes, how can I make it work ? please advice Thank you in advance Amine

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[libvirt-users] question about process power which has MCSx
by yue 18 Apr '13

18 Apr '13

hi,all a qemu-kvm process and its disk(image file) have the same MCS(s0:c111,c555). it express this process have access to this image. i do not know the power to access its image file is the max or min? if any other power this process(domain) has?how much? i want to know the exact power a qemu-kvm process has besides access its image file ,other kinds of files,dirs etc. my test case: after start a guestVM(its disk xml ,cache='none' error_policy='stop'), make some modification on its files and save them. then go to hypervisor, modify the MCS of guestVM's image file. 1.i can read those files(cache=none)?it should not be so. why? 2.then modify files and save, the guestVM hang, it is paused on UI. this is right qeum process can not write again. why this guestVM is hang? and can not be resumed 3.look at audit info. denied { write } for pid=52162 comm="qemu-kvm". that pid is 52162, is not my qemu-kvm's pid? why? thanks so much.

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[libvirt-users] libvirt support for qcow2 rebase?
by Skardal, Harald 18 Apr '13

18 Apr '13

I have not found support in libvirt (nor virsh) for doing the equivalent of "qemu-img rebase ....". The use case: You have copied a qcow2 stack and the new files have different names or reside in a different directory. Therefore you need to change the backing file. Is there a way to do this? Is this a planned addition to libvirt? Harald

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