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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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 ...
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530 views

QEMU USB passthrough is not working

I stuck at getting USB passthrough working with Windows 8.1 guest OS on Ubuntu Server 14.04. I started by installing qemu using the Ubuntu Documentation (https://help.ubuntu.com/community/KVM). The ...
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212 views

KVM NIC passthrough “device already in use”

I have a server with 2 NICs 01:00.0 Ethernet controller: Intel Corporation Ethernet Controller 10-Gigabit X540-AT2 (rev 01) 01:00.1 Ethernet controller: Intel Corporation Ethernet Controller ...
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99 views

Add a second bridge to a virtual machine

We have a ubuntu-12.04 host running another ubuntu-12.04 virtual machine with kvm virtualization and bridged network interface on eth4. This network allows the virtual machine access to the outside ...
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83 views

Linux swap partition not mounted by systemd on boot after dist-upgrade

Recently, I performed a dist-upgrade from Debian Wheezy to Jessie. The upgrade was performed without any error but after the upgrade the swap partition was no longer mounted/activated. The mentioned ...
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199 views

tuning tips for CPU load for OpenBSD guest on qemu-kvm Server

I have a CentOS KVM Server running 1 OpenBSD, 1 CentOS and 2 FreeBSD guests. Only the openBSD guest has a higher CPU load on the KVM Server. 8-10% on Server whilst Guest is at idle. The only service ...
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129 views

how to enable L3 cache on kvm guest?

I start a kvm guest(centos6.5) on a Intel machine(centos6.5),use libvirt, the guest's xml as follow <domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'> <name>...
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117 views

“Nosy Neighbor” and the CFQ scheduler

I'm trying to understand how does using CFQ affects the "Nosy Neighbor" problem. I'll ask it a bit naively, can a "Nosy Neighbor" even exist when using CFQ? Isn't that CFQ should make sure all ...
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392 views

How do I get IPv6 packets to my KVM virtual machine?

My setup is: Debian Wheezy x64 on the host and on the guest. I am using a tun/tap setup to connect a virtual machine to the host. The KVM network options I use are: -net nic,macaddr=DE:AD:BE:EF:1A:...
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221 views

Exchange 2010 on KVM - CPU usage reporting incorrectly

Good Morning, I have virtualized an exchange server using KVM (proxmox actually). It is Exchange 2010 SP3 running on server 2012 R2. KVM version 1.7.1. I am using the latest (0.1-74) virtio ...
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88 views

Change sender-IP for VM in libvirt behind NAT

I have a server with my own public /28 IPv4 Network. On this server I have some vServers, done with KVM/libvirt. These vServers are connected with a virtual network, NATed to the internet. Every ...
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119 views

How to relate cloudstack volume ID to guest virtual block device ID?

Under CloudStack 4.2.1, I have an Ubuntu 14.04 guest with 3 attached volumes of the same size. From the CloudStack management page, I can see that each attached volume has a name and an ID (and a ...
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150 views

__ticket_spinlock high cpu

We are having a strange problem on our Ubuntu 10.04 KVM infrastructure, where periodically, one of two vm webservers freaks out, with persistently high load, even if we restart the applications. (the ...
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1k 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 (...
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887 views

Ubuntu server 13.10: Installing and running Archipel from deb packages

I am setting up a server to host virtual machines based on Ubuntu Saucy. The decision was to use Archipel for remote administration. Installation of ejabber and Web Client UI went smoothly. For the ...
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6k views

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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1k views

virtualbox to qemu but results in no bootable device qemu

I use vagrant to create my development vm. I exported the vmdk to vdi, and then convert the vdi to img. cd virtualbox_dir/test_vm VBoxManage clonehd test_vm.vmdk raw.vdi 0% ..... 100% qemu-img ...
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703 views

preseed command string fail with newline character using virt-install initrd-inject

I am creating a new virtual machine using libvirt's virt-install command. The command pulls a local preseed file from the hypervisor using initrd-inject: virt-install \ --autostart \ --name vm1 \ --...
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953 views

“sched: RT throttling activated” KVM host - what does this mean?

Ubuntu 12.04 64bit - under a KVM parent. 32 cores. So we seem to be having some load issues. We have noticed this line in kern.log: "kernel: sched: RT throttling activated" What does this mean? Is the ...
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246 views

KVM on Ubuntu: Port forwarding to a guest VM

I installed kvm and set several guests on a server using vmbuilder. Here is the following configuration : server host1 (xxx.xxx.xxx.xxx) -> guest vm1 (192.168.0.3) -...
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435 views

KVM host kernel configuration for best performance

I'm currently building a kernel for my server, which should serve for hosting virtual machines using KVM. There are a few kernel configuration options that are already described in the KVM-Wiki. The ...
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379 views

What is the preferred clocksource for a kvm guest running debian?

Our development server is running debian 4.0 (etch) as a guest under KVM. For the longest time, it had sporadic issues where many processes would appear to just hang. We finally found the issue - the ...
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901 views

KVM Guests & IPv6, Connectivity breaks after some time

Goal: Assign public available IPv6 adress to every guest Problem: Working IPv6 connectivity suddenly stops working. After starting everything up (network on host, guests) everything works fine. i can ...
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432 views

How to configure opennebula for allowing a cluster private network to host images with public IPs

I am installing open nebula 3.4.1 for running virtual machines a (kvm based) cluster made of 5 computers: a front-end machine having 2 network interfaces and 4 slaves machines with a single network ...
2
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0answers
121 views

Windows 2k3 server as a KVM client

Just wondering if anyone else has had issues installing Windows 2K3 server under KVM. I have tried a few times tonight and keep getting "not a supported platform" when the installation first boots. ...
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26 views

qemu-kvm VM hangs at iowait with virtio drive

We are seeing instances of a VM hanging with the following symptoms: load average 800, processes stuck, CPU 100% in iowait reading files work, writing files hang the system RAM utilization is high, ...
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22 views

KVM/libvirt: NAT forwarding virtual bridge to host bridge

I currently have a VM setup where only a few 'special' VMs are allowed to have outward facing IP addresses and the rest aren't. All of them are configured with two interfaces attached to a virtual ...
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0answers
30 views

Gentoo virt-manager IO throttling

I have a problem with virt-manager (or qemu/libvirt) installed on gentoo. Here is My virt-manager installed on Debian Jessie: There I have IO throttling but not on my Gentoo: I tried to search ...
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1k views

Using NAT in qemu

I have used Qemu to install a windows xp guest. The command I run is qemu -m 2048 -gda winxp64.img \ -boot d -usbdevice tablet \ -enable-kvm -vnc :10 \ -netdev user,id=network0 -device ...
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82 views

Libvirt & USB Hub Passthrough

I have a virtual machine which I wish to have a USB Hub and all of its devices allocated to a virtual machine. The Hub in question is a USB hub which itself is plugged into one of the ports on the ...
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31 views

How to do remote calls from server A to B to create virtual machines

This is my first question on serverfault so I hope I'm doing this right as I'm usually on Stackoverflow :-) I have two Ubuntu 14.04 LTS servers, server A and B. Server A runs the web server where ...
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25 views

Libvirt does not see updated LVM volume

All VMs run off an LVM pool. I resized one of the LVM volumes to increase VMs drive copacity. Resized it with lvextend as usual. Everything is successful and lvs shows the new size. Libvirt does not ...
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0answers
132 views

Java application is slow in virtual server (KVM)

I have a Java web application, which runs from JAR, starts embedded Tomcat and is using Spring Boot. Problem is that it runs very slow when running in KVM virtual guest. The same application in the ...
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0answers
43 views

How does Qemu handle memory?

I'm having a real hard time understanding something and I was wondering if anybody has any experience with this and is able to help. I have two KVM VMHosts, one running qemu 2.4.1 and the other ...
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0answers
141 views

KVM bad IO sync performance in Linux guest

I'm setting up virtualized Ubuntu 15.10 guest inside Ubuntu 15.04 server using libvirt and KVM. Storage in host system: # mount | grep ext4 /dev/sda1 on / type ext4 (rw,relatime,errors=remount-ro,...
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0answers
184 views

Proxmox/KVM: Can not clone VM

I would like to create a clone of a KVM machine - yesterday I was able to create a clone of the same machine within some minutes. Now it takes hours and is still stuck an "0%": create full clone of ...
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0answers
14 views

create a kvm/qemu vm from vbox config… network adapter configuration?

I have a virtualbox image and configuration file (.vbox) that I want to run under kvm or qemu. I converted the disk image file to a .qcow2 image file, however I'm not sure if there are any tools that ...
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0answers
176 views

Using KVM with macvtap and VLANs for VM

I want to use the optimizations given for the ASAv (Page 18) which should run with KVM. I am using Ubuntu 14.04 LTS and I should configure macvtap for an higher performance. It just says the ...
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0answers
115 views

KVM - graphic passthrough

My PC have two PCIs and installed CentOS 7. I followed this Document about PCI Passthrough I added iommu and enabled BIOS VT-D grep iommu /boot/grub2/grub.cfg linux16 /vmlinuz-3.10.0-229....
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0answers
165 views

XFS/EXT4: Why is actual file size on disk larger than apparent size? Clarification

On a CentOS 7.1.1503 (3.10.0-229.el7.x86_64) system running KVM/qemu on an XFS filesystem, I'm attempting to work out what specifically is adding additional space to a VM diskimage file. $ ls -ls --...
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112 views

Set custom cpu string for qemu/kvm

I have some virtual machines with software, which licensing check depends on cpu string. They're running on kvm - with default cpu string value - which is QEMU Virtual CPU version 1.7.1 After ...
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0answers
152 views

kvm guest routing with 2 default gateways

I have a kvm guest with two virtual NIC. NIC with internal IP III.III.III.III (eth0) NIC with external IP EEE.EEE.EEE.EEE(eth1) I'm using macvtap. The host has his own external IP. I can ping ...
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0answers
193 views

Why are Windows XP and 7 qemu/kvm guests not recognizing updates to a local Samba share?

I develop cross-platform software and test the Windows ports with wine, Windows XP, and Windows 7, the latter two tested using qemu with KVM. I also have several versions of OS X and Debian Wheezy as ...
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14 views

Start a script on ganeti node after instance is started or migrated

There is a ganeti cluster. Is there any way to run script on ganeti node after some instance is start running on that node? In both situations - starting from scratch, and migrating live from another ...
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0answers
113 views

Can't connect to Windows Server 2012 Virtual Machine in Red Hat 6

I have installed a WS2012R2 virtual machine using KVM on Red Hat, It has a bridge connection, Both (Host and Guest) have public IP addresses, both have internet access, both can ping any ip address or ...
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0answers
35 views

Routing private IPv4 addresses internally

I have the following set-up involving two KVM hosts and numerous virtual machine guests on each. The guests communicate to each other on both hosts via [192.168.216.0/24]. [192.168.216.42] is ...
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0answers
139 views

Access to equally defined VM in different VLANs

I have a working libvirt cluster and in order to perform some paralellization I have duplicated it. At the moment my scenario looks like this: two clusters whose VM definitions are exactly the same, i....
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0answers
215 views

Can't get a PowerKVM guest's network to work

I've been stuck by this issue for a couple of days. I am running a Ubuntu 14.04 guest on top of a PowerKVM host (PowerKVM is KVM on IBM's Power Systems, so basically it's just KVM.). I can't get the ...
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0answers
169 views

Debian KVM Host, Debian guests : where full-disk encryption should be done?

I have a host under Debian Wheezy, running qemu/KVM. I want to have all my guests fully-encrypted. I can see to possibilities : - Either I encrypt the LVM Volume using dm-crypt (cryptsetup) and use ...
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254 views

When i use virt-install --import, virsh vol-list --pool default return null

I upload my guaji.img file to server, and use following code: sudo virt-install -n guaji -r 512 --os-type=windows --os-variant=winxp --disk #{to_rmt},device=disk,bus=virtio --noautoconsole --import ...