Questions tagged [qemu]
QEMU stands for "Quick EMUlator" and is a processor emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port to new host CPU architectures.
650 questions
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Qemu virtual machine not responding through VPN
I have a machine with openvpn server and some virtual machines on it. I used to have them in VirtualBox (network: bridge) but I'm moving to QEMU.
Everything except the machine that I've moved to QEMU ...
- 21
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How to set bridge networking for an Ubuntu Server Qemu VM in FreeBSD?
My computer is running FreeBSD 14.1 and has a wireless network wlan0.
joseccz@tigerbsd:~ $ cat /etc/os-release
NAME=FreeBSD
VERSION="14.1-RELEASE-p6"
VERSION_ID="14.1"
ID=freebsd
...
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31
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Recover corrupted qcow image
I have a VM running on qemu on ARM from a qcow2 image, unfortunately my image was damaged and now doesn't boot.
Using qemu-img check returns over 7 000 errors (so much that the logfile is too big for ...
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GnuTLS error signal 4 on QEMU/KVM with cpu set to "host-model"
In order to be able to script VM generation on our Debian 11 QEMU/KVM hosts I wrote a little python script which uses virt-install to setup new virtual machines (with OS Ubuntu 22.04). In those VMs ...
- 83
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44
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User Mode Networking between multiple Guests in Qemu
Is it possible in QEMU to create a user mode netdev (so no tap device or similiar) that multiple guests can use to communicate with each other?
In the documentation I've seen the netdev=socket,connect=...
- 101
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52
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qemu Harddisk slow access (>10 seconds)
I'm trying to set up multiple Windows guests on a Linux server using KVM / qemu and I'm getting abysmal response on disk reads and writes. Windows 11 Task Manager on one guest is reporting disk ...
- 2,633
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75
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Make libvirt guest able to receive multicast traffic from the host network
I have a network defined by libvirt,
The problem
From the guest I cannot query the devices that are connected to the LAN, nor does the guest see multi-cast traffic which the host is able to see.
The ...
- 101
3
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1
answer
144
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Will moving Windows VM's from VMware ESXi to RH9 KVM cause Windows activation?
We are planning to migrate away from VMware ESXi for our company servers. We have a LOT of Windows virtual machines used for testing (different configurations, combinations of options, etc) in our ...
- 1,932
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1
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375
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quemu-guest-agent not starting after reboot
I spun up 3 new VMs this weekend, 2 Debian headless servers and 1 Mint-Cinnamon desktop VM. For all 3 of them, the qemu-guest-agent will not start automatically and I have to manually run systemctl ...
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Solved - Fedora host, Windows guest (QEMU/KVM): NAT'd virtual bridges work except this one (USB/Ethernet)
Quick overview of the situation
I have a Fedora host on which there are multiple NICs and VMs (QEMU/KVM/LibVirt). Each guest accesses the internet via a virtual bridge that operates in NAT mode and ...
- 23
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244
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Migrate from qemu to libvirt
I'm trying to run Bliss OS through QEMU by following this guide:
$ qemu-system-x86_64 \
-enable-kvm \
-M q35 \
-m 4096 -smp 4 -cpu host \
-bios /usr/share/ovmf/x64/OVMF....
- 41
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1
answer
175
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Removing a snapshot from a QCOW2 image on the fly
Is that possible to delete a snapshot from a QCOW2 image without shutting down a virtual machine (QEMU+KVM)? Wouldn't running qemu-img snapshot -d ... break data consistency? If so, would that break ...
- 619
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Poor network performance with NIC virtio on Virt-Manager on Arch guest
My host is EndeavourOS.
My guest is CachyOS.
When I configure on the Virt-Manager the device model for the NIC to virtio I am getting speed of 1-3 Mbps. My internet is 1Gbps.
When I select device ...
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1
answer
113
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mprotect errors at qemu-system-x86_64 startup
I just updated my Alpine Linux to version 3.20, and I encountered this error:
phy0:~# qemu-system-x86_64
qemu-system-x86_64: qemu_mprotect__osdep: mprotect failed: Permission denied
qemu-system-x86_64:...
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2
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2
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459
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Do I need to verify file integrity after running qemu-img convert?
I'm running some v2v conversions to convert disk images from .vmdk to .img using the qemu-img convert utility. The .vmdk file is stored in the RAW format and the output .img file is also going to be ...
- 21
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97
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Logical Volume LVM in External Disk 8T data storage, how to put back and mirgate into new host server?
I recently moved to a new LVM host server, following LVM instructions that export and import which are successful. All lv are in an external disk(8T NAS)
Qemu libvirt network bridge0 setup is working ...
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76
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VMs in nat network not reachable by the host. Guest Virtual interfaces not showing. (QEMU / KVM - VirtManager)
First of all, sorry for the lack of technical details. Virtualization is not my area of expertise.
I use QEMU / KVM with Virt manager to manage some VMs I use for personal labs and testing on my ...
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194
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How can I prevent qcow2 images used by KVM from growing indefinitely on the hypervisor's file system?
I have a number of KVM virtual machines that use qcow2 images to store their data on.
The size of the file system within the virtual machine is of course limited. Most of the time I use LVM with ext4 ...
- 6,599
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22
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How to fake an armhf (arm32v7) arch on automated CICD pipelines without root privileges
In my current organization we have physical CICD runners that have been installed with qemu, and the binaries have been registered in binfmt to automatically start qemu when an armv7/armhf binary is ...
- 11
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1k
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Connect two QEMU VMs
I created two QEMU VMs using Ubuntu cloud images. Then, I started them and enabled the ssh port forwarding using the following command:
qemu-system-x86_64 -m 4G -smp 4 -hda ./ubuntu2404-vm0.img \
...
- 123
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94
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Streaming video from guest to host QEMU
I have Linux on my computer.
Windows is installed in the QEMU virtual machine.
A webcam has been added to the virtual machine.
What is the best way to transfer an image from a virtual machine's webcam ...
- 1
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68
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GRE and QEMU and TAP
HOST SERVER
ENO2 has Internal IP 192.168.55.128 and External IP 200.100.100.100
TAP0 has Internal IP 192.168.10.1
GRE1 has Internal IP 10.10.4.243 and External IP 165.100.100.100
VM SERVER
eth1 has ...
- 1
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36
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Enable ethtool statistics in a QEMU CentOS Guest OS
I have a network interface available in a QEMU Guest OS running CentOS 7, and on the Host OS side it reports as:
$ virsh domiflist --domain mydomain
Interface Type Source Model MAC
-...
- 115
9
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4
answers
3k
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What is the the purpose of using paravirtualization if there is a hardware assisted virtualization?
I am doing a research about QEMU/KVM and Firecracker/KVM.
As far as I understood, both Firecracker and QEMU communicates with KVM to eventually benefit hardware assisted virtualization by changing CPU ...
- 93
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1k
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Wireless-Bridge on a ubuntu 22.04 (netplan) for three QEMU VMs
I do have an apparently trivial, but it is rather an ambitious project.
Wishing to run three ubuntu 22.04 VMs on my laptop, installing and configuring kubernetes for an initial learning phase with the ...
- 111
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1
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231
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Qemu linux guest disconnected randomly
I have a mac m1 with an arm processor and I want to use Linux sometimes.
For this I followed this guide and everything is working as expected and I have a working Linux guest. The only thing I added ...
- 21
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329
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How do I remove cloud-init backing image from my VM?
I am moving a VM from Ubuntu 22.04.3 LTS KVM host to a RHEL 8.9 Ootpa KVM host.
When I try to start the VM on the destination (RHEL) host I see,
error: Cannot access backing file '/var/iso/jammy-...
- 959
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1
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322
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Set Maximum cpu qemu/libvirt almalinux
I want ask to increase supported CPU core on qemu kvm. When I creating new VM I see error like below
error: internal error: QEMU unexpectedly closed the monitor (vm='ID'):
qemu-system-x86_64: -accel ...
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1
answer
81
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Run QEMU command with cron
I have a machine that, aside of other services, needs to run a server VM. I'm running the VM with:
qemu-system-x86_64 -nographic \
-enable-kvm \
-m 8G \
-smp 2 \
-hda gw_disk.qcow2
...
- 3
4
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1
answer
644
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How to sucessfully import an .ova vm exported from ovirt/kvm (Red Hat OS)?
So, I was given an .ova file. This is exported from a server using a combination of KVM/QEMU and ovirt technologie - the server runs RedHat and I want to import this .ova file into vmware or ...
- 41
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vote
1
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711
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Cannot access deb.debian.org from VM after port forwarding using /etc/libvirt/hooks/qemu
Setup
On host server with Debian Bookworm I created two VM-s (pserver 192.168.122.227 and pagent-1 192.168.122.126) via cockpit (kvm). Both of them are running Debian Bullseye. I am using default ...
- 123
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225
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KVM virt-install issue
I want to run arch linux as guest but after virt-install screen is stuck at console Escape character is ^] (Ctrl + ]).However VMs install by virt-manager are working fine and console is also working ...
- 11
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1
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2k
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Changing KVM VM listening on 5901 to some other port
OK this is rather silly, but real problem.
vncserver keeps binding on 5902 port. That is because qemu is listening on 5900 and 5901:
% netstat -lntup
Active Internet connections (only servers)
Proto ...
- 1,551
-1
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1
answer
587
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Making all Linux network interface (bridged) in a qemu VM use dhcp
I have a small application which takes in kernel code, and spins up VMs. I've been using this for kernel development. It is helpful and very fast when I want to spin up VMs with different kernel codes....
- 49
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2
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365
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How to access service from virtual machine of another machine in local network?
I have two Ubuntu machines A and B in my local network.
Computer B has an openmediavault instance set up via KVM.
Computer B has the IP address 192.168.177.58, the openmediavault instance provides a ...
- 101
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284
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Machine type issue when migrating KVM VMs with live snapshots from Debian to Ubuntu
I'm trying to migrate around 40 KVM VMs (containing a few hundred live snapshots mostly used for automated testing on Windows) from a Ubuntu 22 server to a Debian 11 server. The machine type of most ...
- 11
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694
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Why qemu fails to start host only network on loopback when there's no other network on host?
Starting qemu-system-x86_64 with -nic user,ipv6=off,hostfwd=tcp::9022-:22
With only the lo interface (with 127.0.0.1 associated to it) present on the host, the vm will start, but any daemon trying to ...
- 239
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QEMU SMP options
I'm trying to understand the QEMU smp option.
Currently I have set it to:
smp 4
As far as I understand that should create 4 vCPU (with 1 core and 1 thread I suppose).
Would it be better for ...
- 355
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vote
1
answer
2k
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Determine QEMU KVM overhead?
My guest OS shows about 5 percent CPU usage, but my host machine shows the QEMU process taking about 25 percent.
I'm trying to understand where this difference comes from, as I am using KVM ...
- 355
2
votes
1
answer
3k
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Dynamic CPU allocation/scaling in QEMU KVM
How can I dynamically allocate/scale CPU resources to my QEMU VM according to the workload of the VM? Would this require a script? Is it even possible to change CPU allocation at runtime?
I have a ...
- 203
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16
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Can you use virsh to reset vm id sequence? [duplicate]
Question in regards to "Id" for running VMs, using virsh running local Qemu VMs.
command virsh list will bring up a list of the current running VMs defined, eg,
Id Name State
--------------...
0
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0
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228
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qemu set different dynamic ip address for each machine
I need to run about 7 virtual machines via qemu at the same time. The problem is that they all have the same public IP address as the host. Is there any way to give them different ip addresses? host ...
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860
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How to properly make a backup of a virtual machine using QEMU only
This questions asks how one can make a backup of a live virtual machine.
The accepted answer says it is possible with QEMU/libvirt.
My question (since the answer doesn't explain it) is how to do a ...
- 101
1
vote
1
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863
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How to use more then 2GB of ram when using running a nested BIOS VM using KVM
I have a Linux host running Debian 11 and on that host, I have a Ubuntu 22.04 VM. Inside that VM I want to run a Windows 10 VM using nested virtualization. The ubuntu VM is booted using EFI and nested ...
- 111
1
vote
1
answer
855
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Occasional packet loss between bridge interfaces
I have two virtualization servers based on libvirt and KVM. And sometimes I see packages get lost on one particular virtual machine. After restarting the virtualization host this problem is solved, ...
- 323
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1
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168
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Can I use OpenStack Rocky with a neoverse-n1?
Situation: For now, I'm stuck on OpenStack Rocky on Ubuntu 18.04.6 and I have some beefy Neoverse-n1 hardware (aarch64, 64-core, 1TB memory) to integrate. Can I accomplish this with on my current OS ...
- 26
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1
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192
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Three virtio-blk devices crashing Windows 10 VM
If three virtio-blk devices are added VM is crashing in the middle of the Windows 10 boot. The attached blockdev has no influence. VM is working fine using two virtio-blk.
qemu-system-x86_64 \
...
-...
- 347
1
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0
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295
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Backing encrypted drive
Creating a backing image for the master image that is encrypted using LUKS:
qemu-img create -f qcow2 -b dev.qcow2 -F qcow2 -o encrypt.format=luks,encrypt.key-secret=dev --object secret,id=dev,data='...
- 347
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1
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304
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How to read qemu fw_cfg value in windows guest?
Unable to find information about how to read -fw_cfg value in windows guest with the help of this: https://github.com/virtio-win/kvm-guest-drivers-windows/tree/master/fwcfg
Related question: https://...
- 347
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0
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192
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How do I force Virt-Manager to use the hosts' llvmpipe renderer so the guests get to use 3D acceleration?
I'm using virt-manager and set "3D Acceleration" as per what was recommended, but I'm getting this error:
qemu_gl_create_compile_shader: compile vertex error 0:2(10): error: GLSL ES 3.00 is ...
- 111