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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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[libvirt-users] Any good writeups of using libvirt with LXC
by brian mullan 18 Apr '13

18 Apr '13

I've been experimenting a bit with using libvirt and LXC. But have not found many good examples of use so far. Anyone got any they can point me to. thanks brian

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[libvirt-users] Update request: When support for live snapshot delete incl coalesce
by Skardal, Harald 17 Apr '13

17 Apr '13

Does the libvirt development team have a sense of when/which version of libvirt will support the deletion of live snapshots, incl. the coalesce. With the restriction that you cannot delete the most recent snapshot! Harald

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[libvirt-users] Shouldn't vol-upload / virStorageVolUpload() be doing some format conversion?
by Guido Winkelmann 16 Apr '13

16 Apr '13

Hi, I just tried using vol-update to copy an image file to a storage pool, and I noticed that, at least in my configuration (qemu backend, storage pool of type "dir"), this command does not appear to be doing any kind of format conversion. It simply copied the source file as-is over the file in which the target volume was stored with no checks whether that even makes sense. The help text to this command says it supports offset and length, which - kinda, sorta - implies that I can write a block of bytes at offset n to a volume, attach that volume to a domain, and then the OS in the guest domain will find exactly the bytes I just wrote at exactly offset n in its newly attached harddisk/CDROM/whatever. Instead, trying to this with anything but raw images would probably just break the image file. AFAICS, in its current form, this command and this API-call are only useful in exactly two scenarios: - Both the source and target image are in raw format - Source and target image are in the same non-raw format (like qcow2 or vmdk) AND you are copying the entire volume at once. In all other cases - source and target are in different formats, source and target are in non-raw and you are trying to write only parts of a volume - this can only lead to a broken image file. As far as I see it, at the layer of abstraction libvirt offers, "volume" should not be synonymous with "the file the file the volume is stored in on disk", but rather with "the volume as a guest machine will get to see it". Regards, Guido

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[libvirt-users] network under session
by Evaggelos Balaskas 16 Apr '13

16 Apr '13

Perhaps a stupid question, but i will give it a try: I have two machines on libvirtd session and network on usermod. Can i (somehow) cross these two machines ? machineA: ip addr add 10.10.10.101/24 dev eth0 ip route add default via 10.10.10.102 dev eth0 machineB: ip addr add 10.10.10.102/24 dev eth0 ip route add default via 10.10.10.101 dev eth0 -- Evaggelos Balaskas - Unix System Engineer http://gr.linkedin.com/in/evaggelosbalaskas

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[libvirt-users] using transport protocol in live migration
by digvijay chauhan 16 Apr '13

16 Apr '13

Hello, I am working on live migration of virtual machine using xen and kvm.If i use qemu+ssh:///system then is the transport protocol used during live migration tcp or ssh?I mean i want to evaluate the performance of transport protocil during live migration using wireshark and netperf tool,so using this command will show tcp performance? Orelse i will have to use qemu+tcp:/// ?

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