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, ...

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Detailed explanation of how virtual machine snapshots work

I would like to fully understand how virtual machine snapshots work. Although I have researched this subject I cannot seem to find a "high-level" overview of how snapshots work practically. My ...
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2answers
106 views

KVM Disk Formats: Portability

I have recently begun experimenting with the KVM virtualization infrastructure. After deployment, I used virt-manager running on a management computer to build my first guest. I notice that, by ...
1
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1answer
270 views

Why is there a socket interface on the host and a character device interface on the guest for virtio-serial?

I am trying to establish a communication channel between the host and one of its guest virtual machine using kvm as a hypervisor. For this, I am using virtio-serial. To create the virtual machine, I ...
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1answer
1k views

KVM-Host OS recommendation [closed]

I am about to migrate a server installation (one OS) to a newer hardware and wish to enable/use KVM. So the hardware is fixed (https://www.hetzner.de/hosting/produkte_rootserver/ex40) , now I got the ...
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1answer
195 views

assign public IPs to vm guests

I have a set of public IPs for virtual machines. Each unique public IP is to be assigned to a unique guest. With bridged networking I share eth0 with KVM machines. The ifcfg-eth0 file has ...
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2answers
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How to assign multiple public IP address for 3 KVM guest using a single NIC [closed]

i've a CentOS 6.5 KVM Host with 3 KVM-Guest CentOS 6.5. Now I want to assign a public IP for the host and one public IP for each guest using a single network interface. My IPs (assigned by network ...
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0answers
71 views

Bridging Adapter in Ubuntu 12.04 LTS for KVM

Fresh install of Ubuntu 12.04 LTS with libvert/KVM installed. I have 2 virtual machines that I need need to be on the same LAN as the host. The host has two physical interfaces eth0 and eth1. eth1 is ...
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1answer
168 views

QEMU's QMP to listen on same socket?

Is it possible to have multiple qemu processes (machines) to listen on the same socket? I.e. you have this identical part when starting qemu processes: -qmp unix:./qmp-sock,server,nowait --monitor ...
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1answer
1k views

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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0answers
99 views

VDA Disk Fail / Virtual machine corrupt

I am hoping I can get some help here. I have a server that is hosted with a very large server hosting company and today the server became unavailable. On contacting the company they said that the ...
2
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2answers
165 views

Linux KVM disk cache balancing between host and guest

Let's say you have a base server running several KVM guests. Now with regards to disk I/O caching, it would seem that the base server would cache the I/O in its memory, but wouldn't the guest also ...
4
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1answer
259 views

Private network between two KVM VMs

I'm trying to connect two KVM hosts together with a transparent ethernet link. I'm using Proxmox VE as the host and have configured 2 KVM VEs with ethernet interfaces and joined them to a single ...
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1answer
378 views

Why can't I shutdown running kvm instance?

I have running kvm instance: =# virsh list --all Id Name State ---------------------------------------------------- 2 debian-test running When ...
2
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1answer
362 views

virt-install ignoring vnc port/listen?

I'm trying to create kvm machine on remote host. The host is running debian testing. Did use this command: virt-install --name debian-test \ --os-type=linux \ --os-variant=debianwheezy \ ...
1
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2answers
154 views

KVM Network configuration + VLAN trunck

I am trying to set up a KVM Based solution, I am having trouble configuring the NICs for the VMs from a bridge based on a VLAN interface. My config below : ETH0 : KVM Host Management : ...
3
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1answer
996 views

How to replace QEMU binary with newer version for libvirt live snapshots

This is my first post, so please be gentle. :) My CentOS 6.5 box has a QEMU binary that does not support live external snapshots. This is the command I attempt on the virsh CLI, and its output: ...
0
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1answer
131 views

Using all host resources for a single Windows VM (KVM) - how to improve performance

We're using KVM/qemu on Ubuntu 12.04 to spawn a Windows 2008 R2 VM that uses a lot of host resources (all CPU cores, 4GB RAM). It seems that during a Windows boot that Windows allocates all its ...
2
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0answers
305 views

Please help recovering lost volume group

After a reboot, the volume group on my server completely disappeared. [root@dal01 log]# vgdisplay No volume groups found [root@dal01 /]# lvdisplay No volume groups found [root@dal01 ~]# pvdisplay ...
2
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1answer
1k 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 ...
0
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0answers
827 views

the file-system of kvm virtual machine went to read-only after live migration

I setup my kvm virtualization environment with GlusterFS, the topology as follows: KVM1 ---------- KVM2 --------------KVM3 |----------------------|-------------------------| ...
0
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1answer
124 views

Networking issues KVM

I have a server that is running Debian 7.2. I recently set up KVM on it, and created two VMs. Both VMs are unable to connect to the Internet. I was following a tutorial, and I'm certain I followed the ...
0
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2answers
48 views

My KVM machine can't get the network

I'm setting up a virtualization server for my company based on Fedora 19 and KVM. Our goal is to being able to convert and run a bunch of VirtualBox VMs. So I setup my F19 server, and created a br0 ...
1
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1answer
122 views

libvirt Storage Backend

libvirt supports several storage backends[1] for hosting the image on a different server. We have 6 servers running about 40 VMs. Up to now we use local storage, but to minimize the downtime we want ...
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1answer
294 views

KVM Win 7 Pro + RH virtio net driver

Host: Debian 7.2 x64. Guest Win 7 Pro 32-bit. Virtio disk drivers work flawlessly, but there's a problem with virtio net (netkvm something) drivers. Virtio drivers come from virtio-win-0.1-74.iso. ...
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1answer
312 views

MAXWAIT parameter for bridge on Debian Linux boot

I can't seem to find MAXWAIT setting (bridge initialization time) anywhere in /etc on Debian 7.2 x64. Sometimes default 20s is too short for some reason and I'd like to set it longer.
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1answer
502 views

Debian KVM and location for vm images different than /var/lib/libvirt/images

I have defined storage pool for VMs on ZFS: virsh # pool-dumpxml zfs <pool type='dir'> <name>zfs</name> <uuid>b2fba550-467f-8133-dee8-44ada7d0a807</uuid> ...
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1answer
100 views

Correct way to copy vm disk

I have a VM’s disk to copy from one host to another for live migration. I can think of two ways to copy the VM’s disk. Do a snapshot of the Logical Volume in the original host, create a Logical ...
0
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1answer
299 views

OpenNebula can't start vm after reboot

I installed a fresh install of Debian-7-opennebula-4.4.0-1.tar.gz on a fresh Debian and got a VM to start via sunstone. The output of libvirt was: 2013-12-26 12:48:12.919+0000: starting up LC_ALL=C ...
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1answer
280 views

Knowing when a qemu vm shutdown (initiated via telnet using QMP) is finished

When I start a qemu (Windows Server 2003) virtual machine with -qmp tcp:127.0.0.1:4444,server,nowait I can make it shutdown with the following script #!/bin/bash telnet 127.0.0.1 4444 <<JSON ...
1
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1answer
1k views

Assign ipv6 address to KVM guests on bridge mode

System: CentOS 6.5 Network: Bridge on br0 IPv6: ISP Native /64 block. IPv4: ISP address (not internal LAN) Purpose: To assign IPv6 only to guests (manually), I don't want ipv4 address to be ...
0
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1answer
707 views

how to connect multiple kvm/qemu VM guests in to a subnet [closed]

I want to setup a simple subnetwork of KVM/QEMU guest VMs living on a single host (Fedora 19) for testing purposes. The subnet would contain 3 servers: 1 Debian 6.x eth0 ip: 10.0.0.7 eth1 ...
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1answer
221 views

Access web server on VM from a machine in a different subnet

I cannot access to a web application running on a virtual machine hosted by KVM from a machine in a different subnet. So, I would like to access from the machine 192.168.1.2 (top right in green ...
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2answers
43 views

Is there a way to set up a special user for kvm administration without adding to wheel group?

I'm trying to set up a user to manage kvm machines on a server, but I wanted to know if it would be possible to do without adding the user to the wheel group, as that effectively grants them ...
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2answers
186 views

How to assign IP automatically to a stateless Ubuntu virtual machine?

I plan on creating a reusable template image for deploying my application to multiple virtual machines that may be on different networks and different datacenters. I plan on having full control of ...
2
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2answers
820 views

Ubuntu 12.04 LTS KVM host with a OpenBSD 5.4 guest, `virsh shutdown` not working / freezing guest

I have Ubuntu 12.04 LTS KVM host with a OpenBSD 5.4 guest. I am having an issue with virsh shutdown not working / freezing guest. After calling shutdown, guest freezes and is unresponsive. Any ssh ...
1
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1answer
90 views

Mapping between KVM guest virtual discs and LVM logical volumes

The question is, how do I know which LVM partition corresponds to which virtual KVM disc? I am trying to install a KVM guest (Ubuntu server) on LVM logical volumes. I have used lvcreate to create ...
1
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1answer
255 views

kvm guest can not connect to outside of host, vice versa

I have a vmware vm running ubuntu 12.04 server(name=vmhost), with network bridged and full access to the internet. This vmhost is using the kvm hypervisor and is running a vm(centOS 6.4),network ...
2
votes
1answer
94 views

KVM Raw file size limitations

What are the technical and practical size limitations of raw disk files to be used with KVM? Can I create a 2 or 3TB raw disk file as a data drive for a KVM based windows virtual machine (acutally ...
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votes
1answer
20 views

KVM and external multiple external IPs [closed]

I want to have KVM with several VMs on it. I have several external IPs connected via one interface. As I understand I cannot use bridging if I want to have each VM with external IP. Am I wrong? Is ...
2
votes
2answers
194 views

Exactly how much is backported into RHEL [qemu-kvm specifically]? Only security patches, or perfomance improvments too?

https://access.redhat.com/site/security/updates/backporting/?sc_cid=3093 http://froginapan.blogspot.com/2012/07/redhats-backporting-activity.html As the above two links suggest, only security patches ...
1
vote
1answer
342 views

ovirt vdsm vlan - cant create virtual lan only wan port

I installed ovirt 3.3 on fedora 19 on my server. The Server has one ethernet connection, and it is a WAN so I don't have a LAN ip, or DHCP. I set a bridged interface (ovirtmgmt) on this interface ...
3
votes
1answer
159 views

Production-ready disk deduplication for KVM (Linux)? [closed]

Multiple Windows VMs, all of them with identical software installed (they're clones in fact) that I have to run for administrative+licensing reasons, give me a headache storage-wise. KVM on Linux runs ...
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vote
2answers
100 views

kvm /sys/block/vdX/device/delete?

Why on kvm guest there is not file /sys/block/vdX/device/delete? maybe is like that because i can remove the drive from physical host? I know i can attach and detach virtual disk to kvm guest using ...
3
votes
2answers
195 views

How can I keep important VMs in memory without disabling swap?

VM Host -> Xenon E5-2440 w/ 48G mem... Everything runs CentOS6.5 (2.6.32-431) I have 4 guest VMs running each w/ 2G of memory. Their disk images are local files. The host machine is also running a ...
2
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1answer
57 views

What can be improved in my first qemu/kvm run?

Just started using kvm (qemu? I'm quite fuzzy with the terminology). To test if everything works fine, I created logical volume on my lvm, and then started virtual machine using: qemu-system-x86_64 ...
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0answers
648 views

KVM guest cannot write to 9p share owned by non-root

I am aiming to set up full write access to a 9p share for a KVM guest. Both host and guest have the same users/groups with the same IDs. Both host and guest should be able to write to the share using ...
1
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1answer
1k views

Libvirt: ERROR No domains available for virt type 'hvm', arch 'x86_64', domain type 'kvm'

Installed virt-man like this $ apt-get install virt-manager $ modprobe kvm $ modprobe vhost-net Launching libvirt guest $ virt-install --virt-type kvm \ --name centos-6.5 --ram 1024 \ ...
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1answer
53 views

kvm with paravirtualization support

I am preparing to verify KVM with paravirtualization support(mainly for networking). Does mentioning driver name as vhost is enough to make it run in paravirtualization mode ? I have all options ...
0
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1answer
232 views

Slow VM installation on KVM

I have a standard (not modified) KVM+libvirtd installed on clean Centos 6 machine with 8G of RAM and 8 cores CPU. When I am trying to install guest centos 6 using virt-manager it takes ages to finish ...
3
votes
3answers
1k views

Slow disk I/O in KVM with LVM and md raid5

I have been battling with a kvm setup under debian for two weeks now, specifically with guest I/O disk performance. The system: -Supermicro 1018d-73mtf (X10SL7-F motherboard) -16GB ECC/UB -Intel ...