KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-...

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Getting windows virtio mounted/installed for KVM

There might be an easy answer to this. I have exhausted my search on google for a solution. Here's my problem. I need to get Windows working on a KVM vps with virtualizor CP. As I get into windows ...
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2answers
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Install windows 2012 R2 over KVM-virtualizaton

I'm trying to install Windows Server 2012 R2 over linux KVM-virtualization. The installation process stops and requires drivers to continue. I'm trying with virtio drivers from fedora but doesn't ...
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1answer
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How can I run Startup Repair on a KVM virtualized Windows Server?

I have Windows Server 2008 R2 running virtualized in a KVM virtual machine. Recently the virtual machine decided to stop booting, and it offered to Launch Startup Repair. However, upon entering ...
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4answers
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Forwarding ports to guests in libvirt / KVM

How can I forward ports on a server running libvirt/KVM to specified ports on VM's, when using NAT? For example, the host has a public IP of 1.2.3.4. I want to forward port 80 to 10.0.0.1 and port 22 ...
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3answers
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Snapshot/rollback for libvirt+KVM?

I've recently begun using KVM for my development/test environment on a Linux host system with 8G memory. Prior, I was using VMware Fusion for my virtual environment, but my Macbook only has 2G memory. ...
8
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1answer
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KVM guest io is much slower than host io: is that normal?

I have a Qemu-KVM host system setup on CentOS 6.3. Four 1TB SATA HDDs working in Software RAID10. Guest CentOS 6.3 is installed on separate LVM. People say that they see guest performance almost equal ...
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4answers
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Improving IO with FlashCache

I have a server with 2 HDD's (2x 1 TB), running in RAID 1 (SW-RAID). I want to improve IO performance by using flashcache. There are running KVM virtual machines on it, using LVM. Regarding this, I ...
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1answer
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windows server 2012 resolution woes with vga

I have two windows vms, windows server 2012 and windows server 2008. Both use kvm and libvirt. I recently decided I wanted to increase my screen resolution options, which required changing from the ...
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4answers
16k views

Virtualized CPU cores vs. threads

We've got a KVM host system on Ubuntu 9.10 with a newer Quad-core Xeon CPU with hyperthreading. As detailed on Intel's product page, the processor has 4 cores but 8 threads. /proc/cpuinfo and htop ...
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5answers
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How to automatically start VM created by virt-manager?

I have created a virtual machine with virt-manager that runs on kvm/qemu. The machine works well when started through virt-manager. However, I would like to be able to start and stop the VM through ...
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8answers
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Virtualization: Guest in guest?

Does it make any sense to run a virtual machine with a "master" guest, and in that master guest run many other guests? Has anyone tested this? Is it even possible? Are there better ways to accomplish ...
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2answers
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KVM to Xen migration

I've recently been appointed to create some VMs for production use, and went gung ho into making a KVM based VM instead of finding out what our production server uses. I've only recently found out ...
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1answer
551 views

Persistent Network Configuration using KVM and libvirt

Our environment will have a KVM host setup dynamically using kickstart (easy enough). The hard part is dealing with network configuration and keeping VLAN configuration (and possibly bridge/host ...
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2answers
42k views

Difference between KVM and QEMU

I have been reading about KVM and Qemu for sometime. As of now I have a clear understanding of what they do. KVM supports hardware virtualization to provide near native performance to the Guest ...
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7answers
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Xen vs KVM in performance

What is faster on same hardware - Xen or KVM? I'm trying to pick-up a virtualization technology to work, which gives the best performance. There are some benchmarks here that I found on the subject: ...
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6answers
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KVM Guest installed from console. But how to get to the guest's console?

I'm trying to install a fully virtualized guest (Fedora 14 x86_64) on KVM (RHEL 6), using command-line only (both hypervisor and guest). It goes without errors, and without a tangible result . I'd ...
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5answers
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KVM: Which CPU features make VMs run better?

We are using Ubuntu 12.04 with the following parameters: Dell R910 Kernel 3.2.0-25-generic #40-Ubuntu SMP x86_64 x86_64 x86_64 GNU/Linux kvm 1:84+dfsg-0ubuntu16+1.0+noroms+0ubuntu13 qemu-kvm 1.0+...
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4answers
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KVM/qemu - use LVM volumes directly without image file?

I'm not quite sure how to phrase this question (hence the poor title), so let me provide an example of what I'm trying to do. On my (old) Xen host, I'm able to present LVM filesystems directly to ...
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2answers
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KVM on Illumos (OpenIndiana vs. SmartOS)

I'm considering virtualizing a number of guests onto a single server running a recent port of KVM to Illumos. It sounds like my two primary options will be OpenIndiana and SmartOS. The distribution ...
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2answers
6k views

Backup of KVM guests when using qcow2 disk files

I got a Ubuntu (hardy) system used for virtualization using KVM. Each guest got it's own qcow2 file used as disk. Guests are running Ubuntu (hardy). What would a good backup strategy be for such a ...
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1answer
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KVM/Qemu, Ubuntu: Why do more guests CPUs enhance Disk-I/O rapidly?

We have an Heartbeat/DRBD/Pacemaker/KVM/Qemu/libvirt cluster consisting of two nodes. Each node runs Ubuntu 12.04 64 Bit with the following packages/versions: Kernel 3.2.0-32-generic #51-Ubuntu SMP ...
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2answers
3k views

understanding relationship between Qemu and KVM

What is the difference between KVM and Qemu? As I understand, latter is able to provide "user mode emulation" which means that one can run a single executable built for some other architecture like ...
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3answers
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LVM volume group shared between KVM/libvirt host and guests: is this a bad idea?

I have just built a shiny new KVM/libvirt-based virtual machine host, containing 4 SATA II hard drives, and running CentOS 5.5 x86_64. I have decided to create virtual machine disks as logical ...
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votes
2answers
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Strongswan vpn tunnel connected but the traffic is not routed through it

I have just set up a vpn tunnel site-to-site with strongswan (4.5). The tunnel looks fine and connected to the other side, but seems there is a problem routing traffic through the tunnel. Any idea? ...
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7answers
10k views

Get list of DHCP clients with KVM+libvirt?

I have several VMs running on Ubuntu 9.10 via KVM+libvirt. I want to be able to find out the IP address that has been assigned to each host without physically opening a physical "console" to each ...
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2answers
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KVM/Libvirt bridged/routed networking not working on newer guest kernels

I have a dedicated server running Debian 6, with Libvirt (0.9.11.3) and Qemu-KVM (qemu-kvm-1.0+dfsg-11, Debian). I am having a problem getting bridged/routed networking to work in KVM guests with ...
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votes
4answers
5k views

libvirt and qemu/kvm -snapshot option

Using libvirt, I want to use QEMU's '-snapshot' option. That way, when the machine shuts down, all of the disk changes that were made get destroyed. Here is the manual for the -snapshot option: ...
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5answers
7k views

Port Forwarding from Host to Guest with libvirt 0.8.3 Using KVM on Ubuntu

The host has a single external IP available, so I set my KVM guests up with NAT. How do I set up a port forwarding to forward some of the requests from the outside to the guests? I couldn't find ...
4
votes
3answers
3k views

Is KVM stable enough for production use in 2011?

We are planning to virtualize the existing infrastructure by an open source virtualization solution. KVM and Xen are on the final list. Big cloud players are still using Xen, and we found that KVM is ...
4
votes
2answers
1k views

Network freezes with KVM/libvirt and ip_forward = 1

I'm using KVM and libvirt and experience small network freezes on the host and the guests every 2-3 minutes or so. The freezes last 1-2 seconds. The used OS is Ubuntu 10 LTS server edition. I'm ...
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2answers
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KVM on RHEL 6.1 makes host sluggish

I have been running RHEL 5.7 on a host just fine with several VMs (KVM). No major issues. Time came to upgrade to RHEL 6.1 as a few bugs had been fixed in this release. When I start a VM or two under ...
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votes
2answers
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Debian: Should I add vlan interface into bridge for KVM?

I am setting up a Debian Squeeze box as a KVM host. I want to add multiple interfaces to each KVM guest so I want them to be on different VLANs. After reading about this, I believe the best method is ...
3
votes
2answers
13k views

KVM and virtual to physical CPU mapping

I'm a relative late comer to the virtualistion party, so you'll have to forgive me if this seems like an obvious question. If I have a server with 12 cores available, does each KVM guest have access ...
3
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1answer
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Why does host swap out VMs when there are 16GB of buffer cache and swappiness = 0? [duplicate]

I have a desktop running Ubuntu Quantal using OpenStack Folsom on an Intel i5 with 32 GB RAM and 2 GB swap. I'm running 7 VMs each sized like a EC2 m1.small, so 1.7 GB RAM each. I'm using KVM. As I ...
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votes
2answers
16k views

pfSense Site-toSite VPN with OpenVPN connects but won't route traffic

Using two pfSense routers, I've created a shared-key VPN between 2 sites. Both routers are pfSense 1.2.2. The pfSense box at the client site is the gateway router for that site, but at the server ...
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votes
3answers
19k views

How to decrease size of KVM virtual machine disk image

How do you decrease or shrink the size of a KVM virtual machine disk? I allocated a virtual disk of 500GB (stored at /var/lib/libvirt/images/vm1.img), and I'm finding that overkill, so now I'd like ...
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votes
1answer
3k views

DHCP reply packets do not make it into KVM instance in OpenStack

I'm running a KVM instance inside of OpenStack, and it isn't getting an IP address from the DHCP server. Using tcpdump, I can see the request and reply packets on vnet0 of the compute host: # ...
3
votes
1answer
3k views

KVM network bridge with public static IP for both host and guests

I have a Ubuntu 10.04 server with 2 public static addresses. There is a KVM guest (also Ubuntu) installed and running. What i want is to give the guest an IP of the host, so that both machines have ...
2
votes
3answers
5k views

KVM booting off-image kernel and existing partition

I am in the process of switching from Xen to qemu-kvm. My current Xen installation has a number of LVM volumes each with a partition (rather than a full disk image). In Xen, I start each VM with a ...
2
votes
2answers
2k views

Mount LVM within a disk image

I have a disk image that I made with KVM. The partition layout inside the disk image is as follows. [root@centreon01 2tb-external]# fdisk -lu vdisk1.img Device Boot Start End ...
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votes
2answers
2k views

libvirt and network filtering with nat - iptables overrides

At first, I want to say: I know, it was done initially wrong and I want to avoid doing everything again from the scratch because of general downtime. I am running libvirt/KVM on RHEL. I've got VM ...
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vote
1answer
454 views

KVM: Machines unbootable after host reboot

Im finding that my KVM guests are unusable after i reboot my host. Specifically, I always get this error: Booting from hard disk Boot failed: not a bootable disk What causes this error? ...
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vote
1answer
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Adding Virtio block devices at runtime in Libvirt KVM

I'm running Debian Wheezy Beta 4 with KVM based guest systems which run the same operating system. I'm using LibVirt to manage the virtualisation. What I would like to do is to attach an LVM based ...
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votes
1answer
5k views

Use one NIC to create multiple interfaces for Linux KVM

I am working on a thesis research project, and I am having some difficulty figuring out how to make one NIC spawn several "bridge" interfaces such that each KVM VM can be seen on the local network. I ...
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6answers
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KVM online disk resize?

We're evaluting KVM for Linux virtualization on a few projects. All is going well so far. But one of our requirements is the ability to add disk space to a running guest without rebooting or taking it ...
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votes
4answers
7k views

Convert directory to QEMU/KVM virtual disk image

I have a directory filled with data at /var/backups/disk1 that I want to convert into a virtual disk image which I'll then be able to boot using QEMU or KVM (the directory contains the file system for ...
5
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1answer
1k views

KVM virtual machines cannot reach IPv6 web sites

I have a freshly installed Windows Server 2008 R2 SP1 virtual machine which is completely unable to reach any IPv6 web pages, despite apparently having proper IPv6 connectivity. In addition, other ...
5
votes
1answer
3k views

Does kern.hz still have any relevance in FreeBSD if “dynamic tick mode” is enabled?

I'm running a FreeBSD 9.0 setup as a virtual machine in a KVM setup. In previous versions of FreeBSD it was common to force the kern.hz setting to a lower value so that the virtual machine does not ...
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votes
3answers
1k views

KVM “live migration finished” detection

I'm using KVM (through libvirt actually) for a research project. We're live-migrating a virtual machine between different subnets, so after the migration the IP address and routing tables have to be ...
2
votes
3answers
4k views

sysctl.conf not running on boot

At what point is sysctl.conf supposed to be read during boot, and why might it not be running? I have the following settings which are not being applied when I reboot: net.bridge.bridge-nf-call-...