Questions tagged [kvm-virtualization]

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-intel.ko or kvm-amd.ko. KVM also requires a modified QEMU although work is underway to get the required changes upstream.

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Migrate KVM .img to VirtualBox .vdi

I am trying to migrate a VM from KVM to Virtualbox (win7 64bit). I was able to convert the disk image using these commands: VBoxManage convertfromraw -format VDI XX.img XX.vdi qemu-img convert -f ...
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Am I using virtio for my KVM guest?

In one of my KVM guest, when I typed the following command, I get the following /sbin/lsmod | grep vi virtio_balloon 3692 0 So does it mean I am using virtio? Update: When I type cat "...
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What is the best distro to host a KVM virtualization solution

I am looking for a Server oriented distro that we can expect have decent support but also offer as much as possible some of the latest features that KVM might offer. I am leaning towards Ubuntu LTS ...
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1answer
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Assign individual NIC to KVM guest

I have a server with 6 NICs installed and is running Ubuntu 12.04LTS. I want to setup 4 guest VMs using kvm. Now I want to assign 2 NICs for the host(1 Public IP and 1 private IP), and 1 NIC each to 4 ...
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Clone kvm/qemu VM to a different server

What's the easiest/quickest way to clone a VM from one server onto another if you don't have shared storage between the two servers (so you can't do a standard migration)? I have a production ready ...
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Linux-KVM networking advice?

Being new to virtualization in general, and somewhat new to Linux (using Debian Squeeze and coming from BSD) I have a hard time understanding what would be the best network bridging option for my host ...
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Why has CD/DVD host passthrough been disabled in CentOS 7 \ RHEL 7?

I'm learning to use the KVM on CentOS 7 right now. For some reason Red Hat decided to disable the possibility of installing an OS on a virtual machine from a CD\DVD-Rom in RHEL 7. When creating a new ...
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QEMU-KVM Linux virtualization on the command line

I recently discovered that qemu-kvm has a very promising -curses option that, instead of starting an X window, will show a nice ncurses output from the guest suitable for managing a Linux guest from ...
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Alternatives to Xen for virtualization setup

I currently use Xen in production to run a number of Ubuntu VMs (Intrepid/Jaunty). I've got another server which I'd like to set up as a VM host to run more guest OSes, and am looking for the best ...
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Using SR-IOV I350 embedded switch for KVM virtual network — is an external switch required?

I'm connecting several KVM VMs to a virtual network that is routed to a 1Gbit physical network. The router uses netfilter/iptables to filter traffic between the real and virtual networks. For the ...
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WARNING KVM acceleration not available, using 'qemu'

Running debian (Linux Rick 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 (2015-11-09) x86_64 GNU/Linux) Looking at my cpuinfo I can see I have vmx support: flags: fpu vme de pse tsc msr pae mce ...
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Networking between KVM VM and docker container on same host

On a Debian-Stretch host (connected to physical LAN) I have a new docker installation (v18.09) with one database container (port mapped to the host) and I run KVM/libvirt with some Debian-Stretch VMs. ...
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1answer
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virtual disk image - file or partition

I'm looking at the differences between using a file versus a partition to store a virtual disk image in VM use. The common knowledge is that partition-based images are faster than file-based images ...
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Monitor VM's resources (CPU, RAM etc)

I'm testing Openstack and i'd like to know how can i find out about resource utilization inside instances (Virtual Machines). Openstack uses kvm, qemu and libvirt in my testing environment. Is there ...
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TCP/IP performance tuning under KVM/Qemu

With more and more companies switching to public cloud services, I'm curious what you guys' thoughts are on TCP/IP tuning in the cloud. Is it worth bothering with? Given that you don't have access to ...
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Possbile to port a KVM VM to Amazon EC2?

We currently have our own servers that have multiple KVM guests. If we ever decide to move to the Amazon EC2, would it possible to simply copy the VM image over or would I need to begin reconfiguring ...
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Xen vs KVM: Which will have likely better support (read:bugfixes) in the future?

I don't care about GUI or tools, but I do care about stability and performance. If I'm running a FreeBSD firewall and a Opensolaris file server as guests, will I get better stability or performance (...
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How to efficiently share host's folder with KVM guests?

I am configuring the service which stores plenty of files uploaded by nginx in /srv/storage dir on host system. These files are processed by worker KVM guests which may create new files or assign ...
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KVM Guests not booting

I have installed KVM on Ubuntu Oneiric Server 64 AMD. uname -a Linux myhostname 3.0.0-12-server #20-Ubuntu SMP Fri Oct 7 16:36:30 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux I tried creating a guest ...
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What is the difference between RHEV and oVirt?

When I read the wikipedia articles about RHEV and oVirt, I can't really figure out why Red Hat have both projects, as they seam to solve the same problem? http://en.wikipedia.org/wiki/RHEV http://en....
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What is the perfect setup for a small Linux virtual server?

I have my own email server, and it serves a couple of dozen users. I need to replace it right now, and I want the replacement to be a virtual server image running under a hypervisor. My plans for ...
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How do I migrate a KVM guest from host to another?

I have a KVM guest that I need to migrate from one host to another. The migration does not need to be done hot. Its storage is currently backed by LVM block devices, with a bridged network adapter. ...
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optimal settings for win7 64 guest on kvm 64 host managed with libvirt

I am using libvirt to control kvm on a fairly new (core i3) host running Debian Squeeze amd64. The Host as well as Linux guests work and feel fast and responsive. Simply installing Win7 with virt-...
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1answer
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Prevent hijacking IPs in KVM/libvirt

How can I prevent a VM user/client from accessing IP addresses he doesn't own but are routed over the same bridge on KVM/Libvirt? IP addresses are routed to a cisco switch vLan consisting of a /24 ...
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How can I change Qemu KVM machine architecture from 440fx to q35 with virsh edit or virt-manager

Still trying to get GPU passthrough working and decided to change machine type from older 440fx to q35 ie pc-q35 but if I do virsh edit on the config it refuse to save saying "PCI Bridges not ...
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1answer
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VT enabled in BIOS but KVM failed to detect

I Have Dell OPTIPLEX 755 machine with VT enabled in BIOS but when i trying to check using KVM i am getting following error I am missing something? root@nova-controller:~# kvm-ok INFO: /dev/kvm does ...
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How to Restart Centos 7 KVM Host safely without corrupting guest VMs/data?

I want to have a KVM virtualized server with few VMs (with different Guest OSs) in production. Now when I want to install kernel/package updates for the host machine, how to restart the hypervisor ...
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Remote desktop to my KVM virtual machine

I've got a dedicated server running Debian 6. I've set up a windows 7 virtual machine using KVM. Now I'm trying to get Remote desktop working. I'm guessing i have to do some port forwarding. The ...
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Optimal kernel configuration and patches for KVM host

I have a server (single socket Nehalem w/ 24GB RAM) acting primarily as a KVM host containing a bunch of Windows Servers and a few (tickless) Linux instances. I usually compile my desktop kernels ...
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kvm low io performance

performance of my setup is quite good (geekbench, how it 'feels', ...) even disc throughput (libvirt on raw lvm-partition) is very close to the raw performance on the server) but IOP/s are as low as ...
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VNC on Vista

I'm using UltraVNC on my Vista machine, and it's giving me very poor performance, even over a 300 mbs network. It seems to be doing screen polling. I looked, and it doesn't look like the video hook ...
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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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Should I use swap in KVM guest?

Now I'm trying to create KVM templates with CentOS and I'm not sure should I create swap partition on guest OS or not. In future it will be lot's of small VPS with 256-1024Mb RAM and if swap partition ...
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kvm and qemu host: Is there a limit for max CPUs (Ubuntu 10.04)?

Today we encountered a really strange behaviour on two identical kvm and qemu hosts (Dell R910). The host systems each have 4 x 10 Cores, which means that 40 physical cores are displayed as 80 within ...
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Server overloaded, acts like out of memory, but thats not true

I have a Centos 6.5 server, running QEMU-KVM virtualization: hardware: 40 CPUs 400 GB RAM software: Kernel: 2.6.32-431.17.1.el6.x86_64 Qemu: 0.12.1.2 Libvirt: 0.10.2 There are 3 guests, with ...
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1answer
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High I/O latency with software RAID, LUKS encrypted and LVM partitioned KVM setup

I found out a performance problems with a Mumble server, which I described in a previous question are caused by an I/O latency problem of unknown origin. As I have no idea what is causing this and how ...
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1answer
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CentOS Kickstart on KVM doesn't clear partition labels

I used a kickstart file with the command clearpart --all --initlabel to make sure anaconda would clear any disks before trying to create and format new partitions. This has worked in the past for me, ...
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Yum update not working on CentOS 6.2 minimal install

Note: This is my first question on the stack exchange network so please give mercy and provide guidance where needed. I have installed a CentOS 6.2 KVM guest and I am having problem getting yum to ...
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1answer
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KVM / QEMU: connect to VM without GUI [closed]

Short Version (Solution is below): I have a Windows PC. I have a Debian server (without desktop environment). I have a Ubuntu VM running on Debian server via KVM/QEMU. Question: How can I connect to ...
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1answer
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losetup -d giving : device busy

I am mounting a KVM disk (LVM) following these commands : # losetup /dev/loop0 foo.img # kpartx -av /dev/loop0 # mount /dev/mapper/loop0p1 /mnt # unmount /mnt # kpartx -dv /dev/loop0 # losetup -d /...
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KVM Guest using Physical SATA disk

Is there a way to get my Ubuntu server (running as a guest in KVM) to use one of the hosts SATA disks? I Want it to have exclusive access and I believe there should be a "native" way. I have googled ...
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How to repair a broken-resized qcow2 disk image for libvirt/kvm?

Today I wanted to increase the size of a VM, so I did what I always do (have done it before): qemu-img resize diskimage.qcow2 +22GB Then the file broke and the VM does not start any more. I tried ...
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No IPv4 address assigned to KVM VM

I'm having trouble setting up KVM w. bridged networking in Ubuntu 10.10. I'm starting my VM through virsh, after this I can see the kvm process and vnet device on the host machine, but the new ...
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2answers
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Linux-KVM: file server as guest or host?

I'm planning on building an Ubuntu server that primarily needs to be a file server, but due to budgetary constraints will likely get used for running virtual images for a couple of different ...
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1answer
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VNC faster than Spice for remote access to KVM guest?

Having used RDP before, I'm not exactly thrilled with the performance I am seeing from VNC to my KVM virtual machines. The KVM host is Ubuntu 12.04 server x64. I've read that Spice is faster, and ...
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2answers
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Can I run a KVM guest with a btrfs subvolume as file system?

I want to run a virtualized Debian stable KVM guest on a Debian stable host (to run untrusted stuff like Skype, Flash or eclipse with third-party plugins). Naturally host and guest will have many ...
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3answers
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KVM: maximum number of cores and amount of memory for VMs

I have a new 8 core machine with 16GB of RAM. I want to run VMs on it using Ubuntu and KVM. Nothing else but SSH will be running on the host. My question is what is the maximum amount of cores and of ...
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1answer
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Simulating a missing superblock error on EXT4 linux system

I'm trying to write reference material for a friend who has power outages a couple of times a year which affect their linux server. This person is not well versed in linux systems administration, so I ...
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For kvm host images. GFS2 or OCFS2 with drbd8?

I want a shared filesystem on top of drbd8 on two nodes. The servers run ubuntu 9.10. I googled a lot, but couldn't find an clear trend what the web community prefers. It's seems that OCFS2 is ...
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Linux KVM on a Virtualbox

Can we install a KVM machine on a virtualbox machine??? Virtual Machine on a Virtual Machine I get the following error when I issue: $ virt-install –-name kvm_client1 –-ram 256 –-disk path=/var/lib/...

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