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[libvirt-users] Creating network bridge without IP address
by Zoltan Lippai 08 Feb '12

08 Feb '12

Hi everyone! I have the following setup: domain0 |-domU1 |-domU2 |-domU3 I am running this with libvirt on a XEN server. Right now the server is connected to our office network, but later it will be in a hosted environment. I need domU1 and domU3 to have a public IP, and all of the domUs and the dom0 should have an internal IP address to communicate with each other. So this is what I would like to achieve: domain0 192.168.122.1 |-domU1 192.168.122.2 192.168.1.45 (later this will be changed to the public IP) |-domU2 192.168.122.3 |-domU3 192.168.122.4 192.168.1.46 (this will also be changed to a public IP) On domain0 I have the following network interfaces: br0 Link encap:Ethernet HWaddr 54:04:a6:66:c4:be inet addr:192.168.1.44 Bcast:192.168.1.255 Mask:255.255.255.0 virbr0 Link encap:Ethernet HWaddr 52:54:00:fe:88:0c inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0 This way everything is working fine, except that I don't want domain0 to have a public IP (which is 192.168.1.44 in this case) So is it possible somehow to setup br0 on domain0 without it having an IP address? Thank you, Zoltan Lippai

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[libvirt-users] virsh & vmxnet3 (VMware) VM
by Florent Paillot 07 Feb '12

07 Feb '12

Hi, I try to install a VMware VM via virsh with a vmxnet3 network card. Virsh sends me an error : "Insufficient video RAM. The maximum resolution of the virtual machine will be limited to 1176x885. To use the configured maximum resolution of 2560x1600, increase the amount of video RAM allocated to this virtual machine by setting svga.vramSize="16384000" in the virtual machine's configuration file." If I edit the VM settings (via vsphere) and set the Video card memory size to "Auto-dectect video setting" I get the error message : " The task was canceled by a user" when I try to start the VM. If I compare a .vmx generated by vsphere and .vmx generated by virsh I see more lines in the vsphere generated .vmx Is it normal ? Thanks .

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Re: [libvirt-users] qcow2 performance
by Trey Dockendorf 06 Feb '12

06 Feb '12

On Mon, Feb 6, 2012 at 2:07 AM, Stefan G. Weichinger <lists(a)xunil.at> wrote: > Am 06.02.2012 03:24, schrieb Trey Dockendorf: >> I wouldn't consider this definitive, but I wrote an article doing >> tests on qcow2 with the variables being preallocation and caching. >> Essentially preallocation + no-cache is the fastest. Article here, >> http://itscblog.tamu.edu/improve-disk-io-performance-in-kvm/. As of >> virt-manager-0.9.0 the only way to generate the qcow2 with >> preallocation is via command line. Details of how are in the article. > > Additional question: > > Doesn't pre-allocation lose its meaning as soon as the image-file is > fully allocated (I mean as soon as it is as big as its maximum size was > defined at start)? > > > Sending response back to list incase someone finds it useful. Preallocation works so that when you create a 100GB image it takes up 100GB from the start. This helps performance because without preallocation the disk would only take up space of whatever is stored on it. So each time you add files the filesystem as to grow the image. With qcow2 the preallocation is just metadata. I've found that ls -lh will show the size correctly but something like "df -h" won't reflect the size of those images, nor will "du -h". - Trey

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[libvirt-users] Network questions
by paul.worner＠thomsonreuters.com 06 Feb '12

06 Feb '12

Hi all, When creating a new network: 1) Is there a way to disable automatic spawning of dnsmasq on network creation? I read that leaving out the <DHCP> section should accomplish this, but that is not what I am seeing. 2) Is there a way to disable automatic installation of iptables rules? 3) For that matter, what is the purpose of the default iptables rule set? Doesn't line 3 let all traffic pass anyway? Thanks, Paul Running libvirt 0.9.2 on Ubuntu 11.10 server. Here's the libvirt network config: RAW CONFIG <network> <name>test</name> <bridge name="virbr%d" stp="off" delay="0"/> <forward mode="route"/> <ip address="192.168.0.1" netmask="255.255.255.0"> </ip> </network> COMMAND virsh net-create test.xml RESULTS virsh net-dumpxml test <network> <name>test</name> <uuid>2eff5e7f-847a-1fbf-ec82-01a46ef0f6c2</uuid> <forward mode='route'/> <bridge name='virbr3' stp='off' delay='0' /> <mac address='52:54:00:47:E6:15'/> <ip address='192.168.0.1' netmask='255.255.255.0'> </ip> </network ps aux | grep dns nobody 4391 0.0 0.0 21616 916 ? S 09:45 0:00 dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/test.pid --conf-file= --except-interface lo --listen-address 192.168.0.1 iptables -L --line-numbers Chain FORWARD (policy ACCEPT) num target prot opt source destination 1 ACCEPT all -- anywhere 192.168.0.0/24 2 ACCEPT all -- 192.168.0.0/24 anywhere 3 ACCEPT all -- anywhere anywhere 4 REJECT all -- anywhere anywhere reject-with icmp-port-unreachable 5 REJECT all -- anywhere anywhere reject-with icmp-port-unreachable

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[libvirt-users] Performance issues with KVM
by Jatin Kumar 05 Feb '12

05 Feb '12

Hello, We are using libvirt over KVM. If we run a single virtual machine on a host then the performance is very good but if more than one vm (with 1:1 provisioning) runs on same host the performance is very poor (specially in case of parallel programming). libvirt version: 0.9.2 qemu-kvm-0.14.1 We are using virtio module also. What could be the possible reasons for this behavior. Please tell me if you need more info. -- Jatin

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[libvirt-users] How to securely license guests?
by David Knierim 05 Feb '12

05 Feb '12

Hi, I have been asked to research and recommend a method to securely license guests on RHEL/KVM 6.2+ hosts. The guests will be running CentOS or RHEL (5.X or 6.2+). The primary driver to license the software is that we will be selling Telecommunications software in countries where it is common to pirate software. As such, we are worried about the software being purchased one time and then multiple instances of the software being used. We plan to use a USB security dongle (I hate that word!) of some kind. If we were running without virtualization, the solution is pretty straight forward. We would install the security dongle on the server and compile the licensing library which accessed the dongle into our code. We understand that this could be circumvented by a dedicated foe, but it would be reasonably secure. However, as soon as the licensed code is running in a guest, things get a lot more complicated. My first thought was that we could use PCI passthrough to map the USB controller to one guest. Unfortunately, they want to have multiple guests access the same security dongle concurrently. I could see using a bridge that is only on the host to allow the guests to communicate with the host which proxies the requests to the security device. However, it would be pretty easy to connect a network tunnel to the bridge which could allow guests at remote sites to access the security dongle and this would allow the licensed software to be replicated. Can anyone recommend a solution or partial solution to this issue? Any thoughts are welcome, David

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[libvirt-users] Deploying OVF on Different virtual platforms
by Nikunj Badjatya 04 Feb '12

04 Feb '12

Hi All, I am new to Virtualization and Libvirt. Pardon if any information is missing.! I am using VMware PowerCLI And Python to automate tasks for managing my Virtual Infrastructure. I have recently come across Libvirt. and have certain questions. Q1. Can Libvirt be used to deploy OVFs on ESX servers.? Q2. If I wrote a script using Libvirt's Python binding ( A simple one, Say turn on/off/suspend VM) , will that script work on different virtualisation platforms.( HyperV, XEN, VMware-ESX ) ? Q3. Is there a suitable reference for Libvirt's Python APIs ? Thanks, Nikunj Bangalore-India

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Re: [libvirt-users] Can a VM tell what host it's on?
by Paul Lussier 03 Feb '12

03 Feb '12

On Thu, Feb 2, 2012 at 2:08 PM, Eric Blake <eblake(a)redhat.com> wrote: > Did you mean for this to go to the list? Yes, sorry :) > On 02/02/2012 12:04 PM, Paul Lussier wrote: >> On Thu, Feb 2, 2012 at 1:52 PM, Eric Blake <eblake(a)redhat.com> wrote: >>> On 02/02/2012 11:33 AM, Whit Blauvelt wrote: >>>> Is there a way internal to a KVM VM to know which host it's running on? >>> >>> No. The ideal hypervisor is one where the guest doesn't even know it is >>> running as a virtual machine. And consider live migration - a guest >>> might not be running on the same host over its lifetime. Therefore, >>> there should be nothing that requires a guest to know which host it is >>> running on. >> >> From a system administration perspective, though, it's imperative to >> know what physical hosts your VMs are running on. Perhaps the VM >> itself doesn't know, but the sysadmin should be able to have some >> means of figuring this out in a dynamic manner, not simply by "keeping >> track" of where VMs are deployed. > > Yes, but that's a different question. It's not the guests' job to know > which host they are running on, rather, it's the management app _outside > of the guests_ that knows which hosts are running which guests. What do you mean by "management app", virt-manager, or something else ? >>> Why do you think you need it? Perhaps if you ask a better question >>> about what you are really trying to solve, we can give a better answer. >> >> Asset tracking, physical host trouble-shooting, etc. If I'm running >> an environment with 2K physical systems, each of which are running 20+ >> VMs, and someone reports a problem with vm-23475, it would be really >> nice to know that I can ask that VM where it is on my network and on >> what physical hosts. Especially if that VM has been around a while >> and possibly migrated to/from several physical systems. > > That's more a question you should be directing to your management app, > not to your guest. Your management app should know which host is > currently running vm-23475; you shouldn't have to directly query > vm-23475 itself (besides, if you treat guests as untrusted code, you > wouldn't want to rely on any answer vm-23475 gave you in the first place). While I agree with you in principle, my impression is that people are not treating guests as untrusted code, but rather, almost exactly like physical hosts. Perhaps I haven't had the luxury of being in a virtual environment where people are doing things the way they were intended :) -- Paul

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[libvirt-users] Can a VM tell what host it's on?
by Whit Blauvelt 02 Feb '12

02 Feb '12

Is there a way internal to a KVM VM to know which host it's running on? It could send a command via ssh to virsh on a host, and learn from that whether the host currently has it running. But is there something within the VM itself which will reveal this? Thanks, Whit

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[libvirt-users] I want to ask How can I get something like id, uuid, its dom0 in the domU ?
by Ming Q 02 Feb '12

02 Feb '12

hello! I'm new here. I want to ask How can I get something like id, uuid, its dom0 in the domU ?

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