- Users - libvirt List Archives

[libvirt-users] Serving DHCP and DNS from a KVM guest
by Adam Reid 08 Feb '11

08 Feb '11

Hello All, I am trying to set up a cobbler server running as a guest on an isolated network. I'm having trouble figuring out how I can forward the DHCP and DNS traffic to this guest instead of DNSMASQ on the host. So far I have only tried to get dhcp working by enabling the 'allow-dhcp-server' on a guest named test and setting the $DHCPSERVER variable through a filterref parameter element. I figure If I can get this working I can use this filter as a basis for DNS. In my guest the filter is applied to the only network interface setting DHCPSERVER to the IP of my cobbler VM. <interface type='network'> <mac address='52:54:00:6b:56:ab'/> <source network='internal'/> <target dev='vnet2'/> <model type='virtio'/> <filterref filter='allow-dhcp-server'> <parameter name='DHCPSERVER' value='192.168.100.2'/> </filterref> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> And the internal network is defined as: <network> <name>internal</name> <uuid>c1aef8ea-9d30-7514-5eb4-5ffbc235cffb</uuid> <bridge name='virbr1' stp='on' delay='0' /> <ip address='192.168.100.1' netmask='255.255.255.0'> </ip> </network> My understanding of the filter is that when it is applied to a hosts interface it should allow DHCP requests to go to a server other than the host system. Is this correct? Are guests allowed to serve DHCP to other guests? Does anyone have any suggestions or experience with this? Thanks in advance, Adam Reid

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[libvirt-users] Libvirt in Windows not working
by arpita k 08 Feb '11

08 Feb '11

Hi, This is Arpita. I am using Libvirt API in the Windows Vista system.VMware is installed over there.I have installed Libvirt and Python 2.6 in the Windows Vista system andhave written a small test file in Python. Here is the code: import libvirt* * import sys conn = libvirt.openReadOnly(None) if conn == None: print *'Failed to open connection to the hypervisor' * sys.exit(1) try: dom0 = conn.lookupByName(*"vmware1"*) except: print *'Failed to find the main domain' * sys.exit(1) print *"Domain 0: id %d running %s"* % (dom0.ID(), dom0.OSType()) print dom0.info() When I am trying to execute this python code I received error message that : ImportError: No module named libvirt Please help me. Regards, Arpita

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[libvirt-users] Disk atomicity...
by Dale Amon 07 Feb '11

07 Feb '11

I suspect the answer is no, as the very idea makes my head hurt, but a confirmation would be nice: Am I correct in assuming that it is a very bad idea to mount a physical disk on both the physical machine and on a hosted VM at the same time? I can imagine getting away with it if one were RO, but not otherwise. Any takers?

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[libvirt-users] Live migration using virsh
by rajalakshmi 06 Feb '11

06 Feb '11

Sir, I am working in cloud environment and i have set up a private cloud using eucalyptus. I am trying to migrate virtual machines within the cloud using virsh migrate command. I could successfully implement it but when i wanted to know the method used to do live migration. I tried to interpret the code. I also saw that they are setting a flag initially if it is live migration and then assigning 1 to variable live. and i also could find that xenDomainMigratePrepare is calling xend_op which in turn is calling xend_op_ext. But i could'n understand the method of migration. Can you please explain the logic?

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[libvirt-users] Network/bridge questions
by Alex 05 Feb '11

05 Feb '11

Hi, I have an fc14 install and would like to install a few kvm guests but am having difficulty with the networking. On the host I have disabled NetworkManager and configured a bridge which has eth0, the only physical interface on the server. I have a dhcp server on the local lan, and if I add a mac address entry to my dhcpd.conf, the guest will find an IP from there. I think somehow the guest interface is not properly being routed through the virtual gateway created by libvirtd, and is instead just routed through br0 directly on the host. What am I missing? Here is some relevant output from some of the things I know: # # brctl show bridge name bridge id STP enabled interfaces br0 8000.485b3961b55c no eth0 vnet0 virbr0 8000.000000000000 yes I don't understand what purpose the vnet0 has, or even how it got there in the first place. Is it necessary, or did I do something wrong here? # virsh net-list --all Name State Autostart ----------------------------------------- default active yes >From the guest xml file in /etc/libvirt/qemu/ <interface type='bridge'> <mac address='52:54:00:a8:c5:9d'/> <source bridge='br0'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> I've also flushed the firewall rules, so I'm sure the dhcp request isn't being blocked. I've also tried changing the br0 above to virbr0, with no change. This is from "net-edit default" in virsh: <network> <name>default</name> <uuid>3d1f153f-fc0f-4de5-98c8-7f99f96f34d6</uuid> <forward mode='nat'/> <bridge name='virbr0' stp='on' delay='0' /> <ip address='192.168.122.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.122.2' end='192.168.122.254' /> </dhcp> </ip> </network> Sure would appreciate any ideas you may have. Thanks, Alex

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[libvirt-users] libvirt, snapshots, LVM, and existing VMs
by Casey Link 05 Feb '11

05 Feb '11

Hello, I am running libvirt 0.8.3 with a couple VMs using a LVM VG that I had previously setup on my host. I did not use the storage pool functionality of libvirt to create the VG in the first place ('pool-list' is empty). Now I want to be able to take snapshots of the VMs. Having read this previous post [1] on the mailing list, I gather that libvirt does indeed support taking snapshots of VMs on an LVM. I suppose I need to create storage pool that includes the <backingStore> element. However, I am not sure how to go about creating this pool and making my existing VMs utilize it. Is what I am trying to do even possible? If so, what is the proper way to go about doing it? Best, Casey Link [1] http://www.redhat.com/archives/libvir-list/2009-February/msg00196.html

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[libvirt-users] Release of libvirt-java 0.4.7
by Bryan Kearney 03 Feb '11

03 Feb '11

I have just released 0.4.7 of libvirt java. There are 2 main items in this release: - Only throw errors on real errors. - Remote non thread safe error reporting - BZ 600819 Incorrect scheduler parameter value passed to native API. You can access the latest version via the following means: Source Code: http://www.libvirt.org/git/?p=libvirt-java.git;a=summary Bundled Source (tarball and SRPM): http://libvirt.org/sources/java/ Maven: http://libvirt.org/maven2/ RPMS are making their way through F-14, F-13, and F12 build systems Thank you! -- bk

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[libvirt-users] iSCSI storage pool questions
by Anthony Goddard 03 Feb '11

03 Feb '11

Hi All, I've been trying to figure out the best way of using an iSCSI SAN with KVM and thanks to a helpful post by Tom Georgoulias that I found on this list (https://www.redhat.com/archives/libvirt-users/2010-May/msg00008.html) it appears I have a solution. What I'm wondering is the following: 1) If I use an iSCSI LUN as the storage pool (instead of creating an LVM VG from this iSCSI LUN manually first and using LVM in libvirt) do I loose any functionality (such as snapshotting)? 2) If I am intending on doing offline & live-migration between hosts, does each host have to connect to the same LUN / storage pool, or should each host have a separate LUN that is stores VMs on and then each host should simply see all of the LUNs so that migration is possible? For example: I create a LUN on the SAN, connect this to host 1 as a pool called "pool 1" and create VMs on it. Then, on host 2, do I connect to the same "pool 1" and create VMs there, or do I just connect to "pool 1" in order to see it (for migrations) but also define "pool 2" from another new LUN on the SAN and create VMs there? Hope that makes sense.. I'm trying to understand in what situations I might get myself in trouble by two hosts performing storage operations at the same time on the same pool (which is unlikely, but I'm trying to figure out where I stand) Thanks! Anthony

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[libvirt-users] virsh : Need help to manage a vm on a remote vmWare
by Etienne GOSSET 02 Feb '11

02 Feb '11

Hello, I'm trying to use the tool virsh of libvirt. I want to manage via CLI a vm on a vmware hypervisor which is hosted on a remote host (Is that what you call the node??). I read a lot of thing on your site but I really don't understand how to do something... I saw that: >virsh edit $your-vm-name I think "$your-vm-name" is the xml file you're talking about? Is it mandatory to use those XML file in order to use virsh? (Because it is very huge!) I also saw this way of using virsh : >virsh --connect esx://user@hypervisorHost://path/to/myVM.vmx Result is: error: invalid argument in libvirt was built without the 'esx' driver What is the problem here? For information, I installed libvirt-0.8.7, can you give me the first step to manage an existing vm hosted on a distant vmWare (via CLI). Thank you in advance.

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[libvirt-users] network-performance
by Orion Poplawski 02 Feb '11

02 Feb '11

I'm just starting to take a look at guest networking performance and am a little disappointed. I'm comparing two setups: Host: Windows Server 2008 R2 Hyper-V Guest: CentOS 5.5 x86_64 Host: CentOS 5.5 x86_64 kvm running libvirt Guest: CentOS 5.5 x86_64 The guests are essentially identical except that I'm running the Microsoft Linux Integration Components synthetic drivers on the windows hosted VM. The libvirt setup uses bridged networking. Running bonnie++ on a nfs mounted filesystem on each guest I'm seeing the libvirt hosted guest get between 16%-35% of the performance of the Hyper-V guest. Is this expected? Is there anything I can do to increase network performance of the kvm guest? -- Orion Poplawski Technical Manager 303-415-9701 x222 NWRA/CoRA Division FAX: 303-415-9702 3380 Mitchell Lane orion(a)cora.nwra.com Boulder, CO 80301 http://www.cora.nwra.com

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