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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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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7 views

virt-manger cannot access VM disk

On a Centos 6.7 I have installed kvm and created a vm with a 30G virtual disk located in /var/lib/libvirt/images/vm1-disk. I created another disk with the following command: virsh vol-create-as ...
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14 views

Add new subnets to KVM Host

I need to assign a handful of /27 subnets to my KVM host node (Centos 6). I routed them correctly at the Cisco switch, so that's all go. Traceroute & ping works fine on gateway on each subnet, ...
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19 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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1answer
83 views

virsh adding x2apic, cache specific options to kvm config

Anybody know the syntax how to add +x2apic to the virtual machines xml files when I edit them with "virsh edit vm"? From the command line it would be starting with this flag: qemu -cpu ...
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18 views

Hardware raid, LVM and KVM cache policy

I have a question about right cache policy for KVM using LVM and hardware raid-controller. So from the bottom: 1. We have LSI RAID controller 9260, 512Mb cache and BBU. Later we also will have ...
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0answers
18 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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3answers
10k views

proxmox KVM routed network with multiple public IPs

I have a dedicated hosting with hetzner. Additionally i have bought a 6IP subnet. My main IP is: 148.111.111.200 My main subnet is: 255.255.255.224 My additional IPs are 148.222.222.1 to ...
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0answers
12 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 ...
2
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1answer
2k views

How to make sysctl network bridge settings persist after a reboot?

I am setting up a notebook for software demo purpose. The machine has 8GB RAM, a Core i7 Intel CPU, a 128GB SSD, and runs Ubuntu 12.04 LTS 64bit. The notebook is used as a KVM host and runs a few KVM ...
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20 views

How to completely migrate Windows Server VMs with no access to hypervisor?

There are two Windows Server VMs (2008R2 & 2012R2) hosted on OVH (via VMware I think). I would like to move away both VMs from OVH to my server running KVM VMs. OVH isn't going to give me any ...
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17 views

How do I properly configure KVM

I have a remote dedicated server on which I have installed KVM. When trying to create my first virtual machine I am unable to ssh to the machine. I assumed that I needed another ip address so I ...
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1answer
1k views

Linux - KVM - very slow disk io

The I/O performance of my new server is pretty low. I Googled and tried everything I can imagine. First of all, here are the Hardware Components: AMD Opteron(tm) Processor 6344 4x Seagate ...
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1answer
20 views

Correct virtio setup on Ubuntu 14.04 64-bit host

At the present moment, my guest is running inside qemu and host is kvm intel, running Ubuntu 14.04, kernel is 4.3.0 stable. From within the guest, when I run "hdparm -i /dev/sdb" on the guest, I ...
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0answers
36 views

How slow can be a QCOW2 vm disk (proxmox/KVM) over NFS (dedicated 1Gbit)?

I'm running 3 proxmox 3.4 nodes using NFS shared storage with a dedicated 1GB network switch. root@lnxvt10:~# pveversion pve-manager/3.4-11/6502936f (running kernel: 2.6.32-43-pve) root@lnxvt10:~# ...
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3answers
4k views

set tap0 using virt-manager for bridged wireless

After 3 days I finally have kvm guests working on the network via wireless (link below - thanks!): My network is 192.168.1.0/24 on the host: sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward" ...
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2answers
9k views

Which is better image format, raw or qcow2, to use as a baseimage for other VMs?

I am using a baseimage and based on that creating many VMs. And now I want to know which is better, qcow2 or raw to use for a baseimage. Moreover, can you please tell me if there is any advantage of ...
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1answer
1k views

qemu-img snapshot on live VM

I have created multiple KVM VMs using QCOW2 images. Each VM has its own qcow2 file and is not based on any backing file. My question is specifically related to snapshots of QCow2 images on these ...
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1answer
2k views

apt-get update can not connect

i run a dedicated ubuntu 10.04 server. i use kvm/libvirt/virsh to run a virtual machine that's also ubuntu 10.04. i bridged the network (1 of 2 IPs is routed via NAT to the LAN, where my VM ...
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1answer
54 views

Unable create/access storage pool in a KVM

I have trouble using storage pools in my KVM setup. I get the following error message whenever I try to use a pool-* command in my virsh shell. virsh # pool-list error: Failed to get the number of ...
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1answer
1k views

Promiscuous mode in KVM

I have cloud system based on Openstack Icehouse-version. Now I want to test newer version of Openstack (Juno) inside my existing cloud. All hosts and guests use Ubuntu 14.04 as their OS. KVM is ...
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15 views

How to create a new domain from an existing base image in virsh

Is there a way of creating a domain with virsh from a base image? I have looked around and found that it is possible using virt-install, however I would prefer it if this was done purely through ...
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1answer
2k views

dnsmasq(as DHCP server) isn't working in KVM+libvirt envirmont

I'm using dnsmasq as DHCP server in VM environment. But It didn't working. I disabled basic DHCP feature in libvirt. <network> <name>default</name> ...
0
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1answer
26 views

Debian server can't connect to outside world and vice versa

At some point within the past 48 hours my KVM server, which had been running without issue for 6 months, went down completely and was unreachable. Using the control panel to my server, I saw that the ...
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0answers
17 views

Assign a large subnet of IPs to KVM Guest VM

I have KVM host node running a few VMs. I create them using SolusVM panel, however they don't have an option to add bulk IPs in one shot to a guest VM which is silly. I'd like to know how I can add a ...
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2answers
1k views

How to mount disk on centos 6.4 KVM server

I have Centos 6.4 on KVM server already up running with couple of sites, now i am almost run out with space so i decide buy from the server provider more gb in order to increase the HDD. I contact the ...
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0answers
18 views

how to assign failover ip into windows vm (ubuntu, kvm)

I purchased a dedicate server (Ubuntu 14.04 LTS amd64) with a failover ip from online.net. And i want to setup a windows vm with failover ip using kvm. I tried myself several times, but all failed. ...
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1answer
1k views

How do I investigate an unresponsive KVM guest?

What steps can I take to investigate a KVM guest that freezes about once every two weeks? By "freezes", I mean there is no response when I try to connect with "ssh" or "virsh console". The host is ...
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1answer
2k views

Debian Jessie Qemu KVM GPU Passthrough to Windows Virtual Machine guest Virt-Manager error Bus PCI not found

I'm having problems with Virt-Manager not wanting to boot a VM and giving error: Error starting domain: internal error: process exited while connecting to monitor: char device redirected to ...
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1answer
15 views

Is a QEMU installation on a raw disk backward compatible?

I create a qemu image like this: qemu-img create -f raw my_disk.raw 2G and (manually) install debian into it: qemu-system-i386 my_disk.raw -enable-kvm -m 1024 -cdrom my_debian_cd.iso Say I do ...
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28 views

CentOS 7 machines can't ping each other over ipv6

I got three machines configured for ipv6: CentOS 7 vm1 - 2602:306:cc2d:f591::a/64 CentOS 7 vm2 - 2602:306:cc2d:f591::b/64 Macbook - 2602:306:cc2d:f591::c/64 The two VMS are on the same host (a ...
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0answers
22 views

Linux / Proxmox KVM machine boots unreliable after migrating to other server

I have a KVM VM running on a Proxmox 2.3 server. The Guest OS inside the KVM machine is an Ubuntu 12.04 LTS 64 bit. I took a consistent backup of the VM (Proxmox VE backup function) and restored the ...
0
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1answer
2k views

Error while creating VM using virt-manager on Xen

After a great struggle I got my XEN installed now I am using virt-manager and trying to create a VM. Since my H/W doesnt support full Virtualization using the Para Virtualization installation over ...
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1answer
1k views

KVM Isolated network between host and guest fails after few hours

I have a KVM CentOS host with several CentOS guests. All of the guests are using a bridge for network communication. The guests have been up and operational for several months and work properly. The ...
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0answers
39 views

FreeBSD 10 guest on qemu/kvm CentOS 7 host

I'm trying to install FreeBSD 10 on CentOS host without using graphics (using only serial console). I've tried: # virt-install -n freebsd-a -r 512 --vcpus=1 --os-variant=freebsd10.0 --graphics none ...
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0answers
37 views

Use a /29 block on a Hetzner KVM Setup

I have been trying to assign the IP's I got from this 5.9.192.32/29 block. I have followed every step in this tutorial, but I end up with no connectivity on the guest VM's. My Host configuration ### ...
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3answers
7k views

libvirt: how can I make a domain start when the host starts?

I would like some of my domains to start automatically when my host starts (I'm using libvirt+KVM on ubuntu). I guess I could put some "virsh start..." statements in rc.local, but is there a way to ...
0
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2answers
1k views

Guest networking not working on Debian Jessie Host server KVM with br0 bridged network

GUESTS networking not working at all. In other words guest can not ping host or lan gateway. I have br0 bridge already created, also brctl show that vnet0 was properly added by KVM to br0 on guest ...
0
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0answers
39 views

Routing host traffic through Linux KVM (pfSense) router

I have a pfSense virtual machine running on a CentOS 7 host. The host has 2 network adapters, enp1s0 and enp3s0. enp3s0 is connected to a bridge br1. My pfSense virtual machine is also connected to ...
0
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1answer
33 views

Linux server, setting up VM with different IP

I just purchased a dedi server (Ubuntu 14.04 LTS) & additional IP's (called Failover IP's) from OVH. I want to setup a KVM virtual machine in order to for them to have their own independent IPs. ...
2
votes
2answers
1k views

upstart pre-stop script

I have libvirt/KVM set up on my Ubuntu and before shutting down the machine I would like it to attempt shutting down the VM's using an ACPI poweroff (virsh shutdown), then I want it to stop shutdown ...
3
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1answer
267 views

Using KVM and VirtualBox VMs concurrently

I am considering moving several of my virtual machines to a single Linux system for a variety of reasons. The problem is that most VMs are KVM-based, but there are a few VirtualBox VMs as well. I ...
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0answers
26 views

ping from internal to external side of gateway doesn't work until one ping from gateway to internal-client

I managed to create isolated network in KVM-QEMU virtual environment. There is a gateway-pc virtual machine which should connect between isolated network and my LAN with dnsmasq installed on this ...
3
votes
1answer
37 views

KVM port binding

I followed this tutorial to install a KVM virtual machine on my ubuntu server. Now i need to bind a port from the guest to the host. I tried several tutorial to bind the port, but nothing worked. My ...
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2answers
2k views

Installing Windows 2012 KVM Guest on Ubuntu 14.10 - unable to VNC into guest

I have a Ubuntu 14.10 (x64) host, and I am using KVM to setup a Windows 2012 R2 guest VM on it. I am using the virt-install command to set things up. I have setup a bridge network in ...
2
votes
2answers
133 views

KVM top shows high CPU load on host for windows7 guest though windows is on idle

we have an virtualization environment with actually 4 VMs (2 x linux, 1 x w2k3, 1 x win7). In the host system (Debian Jessie) top always shows a CPU load of 30-70% (or more) for the qemu process of ...
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0answers
49 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 ...
3
votes
1answer
3k views

OpenVPN connects and access to ip works but not url in browser

I have been struggling for 2 days to setup Openvpn access to one of my servers but something doesn't work. First about my setup: My server is Debian 6 installed on vps on kvm environment. I have ...
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2answers
1k views

Optimizing disk performance on KVM VM configuration

I have a KVM host server running Ubuntu 12.04 LTS, bare bones installation with only KVM installed. The server has an 8 Core Intel(R) Xeon(R) CPU E3-1230 V2 @ 3.30GHz CPU with 32GB of RAM and SATA ...
2
votes
2answers
2k views

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 ...