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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VLAN support with libvirt for linux bridge to virtual machines

I'm using systemd-networkd to configure network interfaces managed by libvirt for KVM (Kernel-based Virtual Machine) with Debian Bullseye on all nodes. I want to have transparent VLAN support on the ...
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KVM Live Migration- VM is already active

I'm trying to perform a live migration from one KVM host to another, both SLES12SP5, share the same subnet. 'kvm_one' hosts the server 'login01'. 'kvm_two' hosts no servers. Executing the following ...
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Arch Linux - QEMU override System Manufacturer on Windows 10

I've fully virtualized a VM with windows 10 on QEMU and had to do host-passthrough in order for it to work. Because there's no way to set SMBIOS to reflect the host, I want to know if there's any way ...
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Virtual storage drive will not mount on virtual machine, read only error

I am running a Ubuntu 18.04 server with kimchi/wok. I use it to run an influx database. Yesterday I noticed my database was not recording data. I tried rebooting my virtual server which uses a ...
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KVM Virtualization Server - One physical disk(SSD) every virtual machine

In terms of performance, is it better to have one "big" SSD disk for several (lets say 5) virtualized guests, or a single smaller SSD disk for every virtual machine? any general draw back ...
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QEMU / KVM - Dedicated 802.1q VLAN for each VM - Communication only via router

I have a Linux firewall router (dedicated machine) with multiple ethN interfaces (my "big firewall"). All forwarded traffic is filtered by a set of iptables rules (default policy DROP). ...
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Raw LVM disk write is four times faster on host than inside KVM guest?

I've got a Debian 10.6 Host, with a Debian 10.6 guest. KVM/Qemu/libvirt. The host has a software RAID 10 array with 6 mechanical disks. LVM is on top of the RAID array. One LV is passed into the guest ...
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Linux bridge does not forward packets to TAP interface

I have the following scenario where I run a Docker container which has configured inside of it a Linux bridge br0 and attached to it I have the main interface eth0 of the container and a TAP interface ...
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Can I customize all my operating systems that I will install on kvm/qemu with Virt-customize?

For my private cloud provider, I want to create a virtual machine from the operating system iso I want using kvm/qemu (since I was looking for an alternative to cloud-init, I chose to customize it ...
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How to enable nested virtualization in order to use VirtualBox inside of a KVM virtual machine?

We have a KVM hypervisor (L0, AMD, Kernel: Linux level0kvmhypervisor 4.19.0-12-amd64 #1 SMP Debian 4.19.152-1 (2020-10-18) x86_64 GNU/Linux), which runs a virtual machine that I would like to use as a ...
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Can't see docker ports from external machines when using a veth interface with an OPNSense KVM

Quick summary of the setup: Ubuntu Server 20.04 with 4 network ports OPNsense router running in libvirt KVM One port is WAN, three ports are LAN (bridged) Router works great Server (same one running ...
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CPU frequency in KVM vps

Is it possible to display CPU max and min frequency in a KVM vps using Libvirt on server ? It only shows CPU mhz in vps and not max and min mhz as seen on server in lscpu command output.
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Resizing VM's size having only boot partition

I've to increase my KVM guest's partition, I followed steps as explained in the accepted answer here. For step 3, there's a link mentioned in the accepted answer comment section (tried to paste it ...
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1answer
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KVM quests “stuttering”/“freezing” intermittently on Debian 10

I'm using KVM on Debian 10 as host and for now two guests that are Debian 10 as well. The guests are "stuttering" frequently, what I mean by that is that like at least several times an hour ...
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Ubuntu KVM - Bridge - Isolate Host from NIC

I have a Ubuntu Server with 4 physical NICs. 2 of them, i want to "hide" from the Host, so the host itself may not access traffic on those 2 nics, just the VM where i pass them into (...
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KVM DNS forwarding not working / reply: REFUSED

I've set up a couple of VMs for development purposes for a project. The setup includes a local CA for the past, current and future project VMs. On the guest if can do dig staging.testing.lan and get ...
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Does add more memory RAM decrease I/O wait?

My server is Ubuntu KVM and has 2 cores, 4GB RAM, and I use HDD, at moment I can't swap HDD to SSD. I found this answear (https://unix.stackexchange.com/a/463819/351968) saying that adding more memory ...
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DisplayPort KVM Switch issues

I have two computers connected via an DispayPort KVM-Switch to two monitors. When i boot one of the computers while it is active on the monitors then i'm getting the correct dual monitor screen on ...
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KVM with 1 vCPU has CPU load above 1

I have a KVM running with 1 vCPU on a machine with 4 cores. lscpu in the KVM gives me 1 CPU with 1 core : Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte ...
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Routing with nftables (Fedora33, nmcli, brctl)

A/ Host (Fedora 33) with Ethernet if eth0. ip 192.168.18.11(/24) and B1/ Kvm guest with if vnet0 enslaved to virbr101. ip 192.168.101.88(/24) (manual routing, static IP) or B2/ Kvm guest with if vnet1 ...
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Where is virsh save directory location defined

The default location of the virsh save myVm goes into /var/lib/something which makes my slash partition full on a Vm save, which is really anoying. I could not figure out where is the virsh save myVm ...
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Ubuntu 20.04 LTS Server - KVM with Spice or VNC

I am wondering if anyone has gotten Spice Server or VNC Server to work remotely on ubuntu 20.04? I would be glad to make a video tutorial once I have it working correctly because I can barely find ...
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Same sysctl kernel parameters for KVM host and guest

I need to set up a KVM guest with the following sysctl kernel parameters: net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 ...
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How to configure properly DRBD and KVM replication?

I have two CentOS KVM servers with some virtual machines: A and B I am running as Primary on A and Secondary on B. When A fails I am able to switch DRBD on B to Primary and access the disk images ...
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how can I utilize a gpu blade server running linux with remote KVMs?

If it possible to combine SR-IOV capable amd cards with linux NTB device Lending so that we can utilise many virtual gpus on KVM's from a remote location, which one is it ? It seems there are three ...
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ZFS inside of virtual machine?

Are there any technical reasons why I shouldn't use ZFS file system inside a VM on a hypervisor on top of hardware RAID? schema.png
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ASMB8-IKVM firmware update

I'm trying update firmware that there is 1.08 to more recent, I look in site official but not gotch result, all versions are defined with "unsuccessful" in verifying the firmware image ...
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iptables not filtering after applying filtering rules to KVM based VM

I am following this serverfault post as I want the guest Centos7 Virtual Machine to access the internet but have no access to any LAN network. My Host machine is Red Hat 7. Here is the output of ...
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equivalent for ifconfig dev 0.0.0.0

When I need to create a temporary bridge with interface on Linux I would use the following: brctl addbr br0 brctl addif br0 eth0 ifconfig eth0 0.0.0.0 ifconfig br0 192.168.10.100 netmask 255.255.255.0 ...
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Debian 10: activating bridge interface on remote host freezes ssh connection

I am working on a fresh installed Debian Buster installation on a remote host located in a data center elsewhere. I have a script ready to copy the working standard /etc/network/interfaces back in ...
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KVM virtualized firewall NIC configuration + iptables

I'm currently considering setting up a virtualized firewall on top of KVM. This virtualized firewall can be Pfsense, Opnsense, Ipfire, whatever basically, haven't decided yet. What I currently was ...
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Cannot virsh start my VM after a reboot of physical machine..error only a single IDE controller is supported?

I have a VM running under kvm (it is a .img file), the server it runs on crashed hard and restarted and finally got things up... I think I goofed and ran yum install -y qemu-kvm Which I am sure ...
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Libvirt guest hostnames DNS resolution from host and guests

I have set up multiple virtual machines with libvirt and kvm on Ubuntu server 20.04, which work just as expected. The only thing I cannot figure out at this point is how to make their hostnames ...
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How to run KVM nested in WSL2 (or vmware)?

I'm trying to follow this tutorial to run KVM nested in WSL 2, but after following the directions through compiling the kernel and loading it, the test kvm-ok reports that KVM is not supported. I've ...
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KVM hypervisor - Windows 32bit VM, RAM up to 2GB usable

I've got a Debian 10 KVM hypervisor, no libvirt or other tool to administrate it, using QEMU scripts. I need a 32bit Windows VM for a legacy app, but on a supported OS (not XP), either Windows 8.1 or ...
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KVM Port Forwarding Port 53 to Guest via NAT - Temporary failure in name resolution

I'm trying to forward port 53 from the host to one of my KVM virtual machine guests on the virtbr0 interface (which uses NAT). The guest VM is going to run a customized DNS server. However, after ...
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KVM host crashes after starting application in guest

We ordered a new dedicated server yesterday and I moved some KVM guest machines from the old KVM host to the new server, which will be our new KVM host. The old KVM host is Intel based and the new one ...
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Linux KVM - Windows 10 VM - Mouse movement delay

I have a Windows 10 VM on my KVM (Libvirt) Linux machine. When i run other VMs like any Linux Distro, the responsiveness is fairly good, almost not noticable. With the win10 vm however, it is supper &...
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Windows vps performance

Windows vps performance is not as expected while I see this message in /var/log/messages. [ 7283.526915] kvm [34279]: vcpu0 disabled perfctr wrmsr: 0xc2 data 0xffff Its a KVM vps on 3.10.0-1127.19.1....
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Is my KVM VM thin provisioned?

I was reading another post here Use Thin LVM Volume for KVM VM trying to understand whether or not KVM is capable of creating thin provisioned VMs. The post from about 8 months ago has both the OP ...
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How to diagnose and fix issues causing libvirt guests to become unbootable after many reboot cycles?

I have encountered a couple of times that a previously functioning Guest simply starts freezing on boot. (I have now reverted my VM to a previous working snapshot, so I cannot directly start up the ...
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1answer
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Restoring terminal/TTY to normal after virt-install?

After having created a VM with virt-install then the terminal is only 24 lines, where the terminal have 70 lines. I recall seeing a similar issue with virsh console. Question Ideally would I like both ...
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135 views

Tagged VLAN on KVM with macvtap driver

I've setup a pfsense guest on KVM and and trying to pass tagged and untagged traffics to the VM for obvious reasons. My setup looks like this --> The KVM has 2 NICs(both virtio type): 1st(for ...
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KVM/QEMU CentOS 8 kickstarted VMs have broken networking, are unreachable

I can't understand why the VMs I create using virt-install & kickstart do not have networking that can be accessed reliably from foreign hosts. The VMs I created using virt-manager can be logged ...
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How to set up kvm vm on separate nic from host in Ubuntu Server 20.04

I am trying to figure out how to setup a vm in Ubuntu Server 20.04 with kvm, but I am not having much luck. The goal is to have the host on the 192.168.20.x network and the vm on the 192.168.10.x. I ...
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Broken USB Forwarding for Dexcom G6 via libvirt qemu kvm

I'm attempting to forward a USB device over from my Linux host (Fedora) to a Windows 10 guest. The device seems to be forwarded, however, Windows cannot use it correctly. Additionally, I've tested ...
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Cannot access guest webserver from host

Here is my configuration, I have a Ubuntu 20.04 host machine with a kvm virtual machine holding a webserver. I set the folowing rules with iptables in order to root the ports 80 and 443 of the host ...
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Windows under KVM hypervisor, constant swaping and a lot of unused RAM

I'm running windows server 2012 VMs with plenty of RAM assigned under Linux KVM. All 4 servers show almost 0% available memory and do a lot of swaping. The RAM used by applications doesn't add up to ...
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Set up KVM host with multiple VLANs, each attached to “its own” external IP address

I'm trying (and having a hard time) to setup a clean KVM environment with: an Ubuntu (20.04) host (with a single NIC), multiple ubuntu KVM guests, 2 public IPs, and one Vlan per IP. Basically ...
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How to find what makes my website speed less?

about some days ago we have found our users with one of our min Internet Carrier have speed problem with our website. after investigation we have found that the speed of website content download slow ...

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