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1610 discussions

Can I have more than 1 bridge attached to a KVM
by Meir Hazon 02 Apr '13

02 Apr '13

Hello Everybody, I have a physical machine with 4 Ethernet cards that I have mapped to 4 bridges. I would like to have each of my KVMs use 2 bridges for NIC bonding. 1. Can I have more than one bridge assign to one KVM? 2. Can I use virt-install to assign a KVM with more than one bridge during the KVM installation? a. It was a long shot but I have tried bridge=br0,br1 ; bridge=br0 bridge=br1 - never worked..... Thanks so much, Meir

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GFS2 hangs after one node going down
by Maurizio Giungato 25 Mar '13

25 Mar '13

Hi guys, my goal is to create a reliable virtualization environment using CentOS 6.4 and KVM, I've three nodes and a clustered GFS2. The enviroment is up and working, but I'm worry for the reliability, if I turn the network interface down on one node to simulate a crash (for example on the node "node6.blade"): 1) GFS2 hangs (processes go in D state) until node6.blade get fenced 2) not only node6.blade get fenced, but also node5.blade! Help me to save my last neurons! Thanks Maurizio

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Problems with qemu img disks allocated in a nfs share
by carlopmart 18 Mar '13

18 Mar '13

Hi all, I have a strange problem with qemu img disks allocated in a nfs share on a CentOS 6.4 host. Every time when I try to start a vm this error appears: char device redirected to /dev/pts/1 qemu-kvm: -drive file=/data/vmachines/win2k12adsrv/win2k12vol01.img,if=none,id=drive-virtio-disk0,format=qcow2,cache=none: could not open disk image /data/vmachines/win2k12adsrv/win2k12vol01.img: Permission denied Obviously, qemu disk exists: [root@c64kvm qemu]# ls -la /data/vmachines/win2k12adsrv/win2k12vol01.img -rw-r--r-- 1 root root 262144 Mar 16 16:11 /data/vmachines/win2k12adsrv/win2k12vol01.img If I change this qemu disk stored in a nfs share by another stored on local disk, all works ok. Mount permissions in this kvm host: sansrv:/ on /exports type nfs4 (rw,rsize=32768,wsize=32768,hard,intr,addr=172.25.60.1,clientaddr=172.25.60.2) and selinux is disabled ... Any idea?? -- CL Martinez carlopmart {at} gmail {d0t} com

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Windows 2012 as a kvm guest
by C. L. Martinez 11 Mar '13

11 Mar '13

Hi all, Has anyone tried it? Virtio drivers works? Any problems or tips?? My idea is to use centos 6.3 as host, at first step until I can test centos 6.4 Thanks.

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Sanlock disk leases on drbd/gfs2 volume
by Russell Jones 09 Mar '13

09 Mar '13

Hi all, I have a 2 node cluster that consists of the following: * 1 drbd/gfs2 partition that holds VM images and XML * Sanlock configured with the disk lease directory on the same drbd/gfs partition Everything is working well, aside from one small issue I ran into. When testing fencing, on one particular test GFS began replaying the journal for the remaining node, and in the middle of it rgmanager attempted to recover the VM. Normally this wouldn't be an issue, as libvirt would just pause until GFS was ready, however since it's talking to sanlock first, sanlock attempted to acquire the lock, while GFS was not ready, and failed. This caused the recovery itself to fail. I'm attempting to keep the lease directory on the shared storage so that I do not have introduce another single point of failure in the cluster by having an outside NFS mount. It seems like I could get around this particular scenario by changing the recovery policy to "restart" (it's on relocate right now), and have it try restarts several times before giving up, but I wanted to see first if you guys had any advice for this issue as well. Perhaps I'm missing a setting that would correct this? Thanks!

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Re: [CentOS-virt] convert xen to kvm
by Peter Mumenthaler 08 Mar '13

08 Mar '13

hi, yes it is possible. use the tool virt-v2v.... cheers peter mattias <mj(a)mjw.se> wrote: >_______________________________________________ >CentOS-virt mailing list >CentOS-virt(a)centos.org >http://lists.centos.org/mailman/listinfo/centos-virt

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convert xen to kvm
by mattias 08 Mar '13

08 Mar '13

i have a xen instance on a lvm partition are it possible to convert it to kvm image? and if so how?

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Need to unmount an LV from host system
by jboyce＠meridianenv.com 06 Mar '13

06 Mar '13

Greetings - Ok, I made a mistake that I need to fix. Fortunately it is not a destructive mistake, but I need some advice on how to correct the problem. CentOS 6.3 host system named Earth I was creating some new logical volumes within my exiting volume group for a new virtual machine using the LVM GUI. When I created the LV that I plan to use for root partition of the new VM (Bacteria) I mistakenly clicked on the box to mount the LV, and specified the mount point as /. [root@earth ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg_mei-lv_earthroot 5.0G 3.9G 880M 82% / tmpfs 5.9G 276K 5.9G 1% /dev/shm /dev/sda1 485M 116M 344M 26% /boot /dev/mapper/vg_mei-lv_earthvar 3.0G 748M 2.1G 27% /var /dev/mapper/vg_mei-lv_bacteriaroot 5.0G 3.9G 880M 82% / I tried to unmount the device, but as shown below, it is busy. [root@earth ~]# umount /dev/mapper/vg_mei-lv_bacteriaroot umount: /: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1)) I tried to force unmount the device, but that failed also. [root@earth ~]# umount -f /dev/mapper/vg_mei-lv_bacteriaroot umount2: Device or resource busy umount: /: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1)) umount2: Device or resource busy What other options are there. Is there are way to get this unmounted without having to shutdown my host system and boot into rescue mode. I don't really want to shutdown my active VM's while other staff are working on them right now. Please cc me directly as I only receive the daily digest. Thanks. Jeff Meridian Environmental

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CentOS 5.9 Xen DomU NFS Data Transfer to Dom0 kills network.
by Veli-Pekka Kestilä 06 Mar '13

06 Mar '13

Greetings, I have problem using Dom0 as NFS(v4)-server and DomU as client. When ever the client actually tries to copy data to nfs-server the virtual network (bridge) between the two hosts completely freezes and stops working. After this of course the client hangs waiting nfs-server to answer and server continues to try to contact nfslock daemon on the client. Dom0 is still accessible from outside trough virbr0 which the client doesn't have access. The problems only come on data transfer as making directories and removing them and doind ls works fine before one tries to transfer data. Anyone have suggestion what could fix this behavior. Veli-Pekka

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Re: [CentOS-virt] Time
by James B. Byrne 17 Feb '13

17 Feb '13

On Wed, January 2, 2013 12:51, SilverTip257 wrote: > On Wed, Jan 2, 2013 at 9:41 AM, James B. Byrne > <byrnejb(a)harte-lyne.ca>wrote: > >> >> I ran into this situation several times whilst testing KVM and the >> lessons I learned from the experiences can be summarized as: >> >> 1. Never allow the kvm hypervisior to handle guests during a host >> shutdown. Use 'virsh shutdown' on each of the guests first and then >> shutdown the host. Use autostart to restart guests on a host's >> reboot. Write a script to process 'virsh list' to feed active >> domains >> to 'virsh shutdown' if automation is required and link that to >> /etc/rc0.d/K10<whatever>. >> >> > @James: Can you specifically cite why you manually power down each > node? Have you tried tweaking your libvirt settings in the config > file I noted in my earlier response to Robert? Two reasons. First, I am minimally familiar with kvm. The niceties of the options for it is beyond my kin for the nonce. Second, libvirt does not always work. I have had guests refuse to either suspend or shutdown from an automatic request to do so. When shutdown is done manually one discovers right away that there is a problem and which guest is causing it. > Set up a central NTP server and have your hosts (and not just VMs) > connect to it. It could be the VM host, but doesn't need to be. > Distribute the load to your NTP server and off of the public NTP pool > by running an NTP server for your servers to poll [0] ... it's a good > practice and everybody is happy. > I do that as well. However, I run one on each host just to serve its own guests and configure the host to run off our central ntp server. > > >> 4. On each guest have a cron job that checks for ntpd at regular >> intervals which reports failures and restarts the time service as >> necessary. We use: >> JOBNAME="Check ntpd status and restart if required" ; \ >> ntpstat > /dev/null && \ >> if [[ $? -gt 0 ]]; then /sbin/service ntpd start; fi >> >> > Why not configure the ntpd daemon and stick with that? > It does update on its own [1]. And ntpstat prints out the interval, > which matches the one mentioned at [1]. > I don't believe the ntpstat script/job is necessary (I've never had to > do more than set ntpd to run after configuring the servers it should > poll). > You misunderstand the purpose of the job. Netstat checks to see if the daemon is actually running. If it is not then netstat returns a non-zero exit code. If the ntpstat exit code is not zero then the service script is invoked to restart it. Additionally, netstat writes out to stderr that it could not find the daemon which gets emailed to support. I probably should have used [[ ! $? -eq 0 ]] but what I have written does work. We found ntpd just stoped on some guests upon occasion without any visible trace of a cause. Not frequently but when it did happen it was a nuisance to detect before clock drift on the guest caused some failure or other. This job detects these occurrences and self corrects. These are all CentOS-6.3 hosts and guests. -- *** E-Mail is NOT a SECURE channel *** James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3

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