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.
634
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Difference between KVM and QEMU
I have been reading about KVM and Qemu for sometime. As of now I have a clear understanding of what they do.
KVM supports hardware virtualization to provide near native performance to the Guest ...
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Is there any way to shrink qcow2 image without converting it raw?
Is there any way to shrink qcow2 image without converting it raw?
I cannot convert it to raw because I don't have disk space enough for raw image.
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free up not used space on a qcow2-image-file on kvm/qemu
we are using kvm/qemu with qcow2-images for our virtual machines.
qcow2 has this nice feature where the image file only allocates the actually needed space by the virtual-machine. but how do i shrink ...
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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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How to start qemu directly in the console (*not* in curses or SDL)
I seem to recall being able to start qemu with only the terminal emulator output, with the graphic window disabled. And here I don't mean with the ncurses interface, that one is nice, but I want the ...
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KVM: Which CPU features make VMs run better?
We are using Ubuntu 12.04 with the following parameters:
Dell R910
Kernel 3.2.0-25-generic #40-Ubuntu SMP x86_64 x86_64 x86_64 GNU/Linux
kvm 1:84+dfsg-0ubuntu16+1.0+noroms+0ubuntu13
qemu-kvm 1.0+...
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understanding relationship between Qemu and KVM
What is the difference between KVM and Qemu? As I understand, latter is able to provide "user mode emulation" which means that one can run a single executable built for some other architecture like ...
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9
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Is there a way to determine which virtual interface belongs to a virtual machine in a kvm host?
I'm using qemu/kvm whith bridged networking. In the host machine there are several "vnetX" network interfaces without IP. I'm looking for a way to know which vnetX belong to a virtual machine.
I ...
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18
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1
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QEMU multiple port forwarding
I would like to forward more than one port.
This command run my VM and forwards RDP port successfully:
qemu-system-i386 -net nic,model=rtl8139 -net user,hostfwd=tcp::3389-:3389 -m 512M -localtime -...
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2
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'Unrecognised disc label' - when using parted with qemu images
I have a Linux from scratch LiveCD running on qemu vm.
I'm using this command to create a hda disc for qemu:
qemu-img.exe create -f qcow2 base-linux.img 5G
Then I run my vm:
qemu.exe -m 1024 -...
- 365
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2
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Read/write access for passthrough (9p) filesystems with libvirt/qemu?
I have recently started experimenting with the support for passthrough filesystems in recent versions of KVM/QEMU/libvirt. Making the filesystems available for read access has "just worked", but I'm ...
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17
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3
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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 ...
- 1,431
13
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6
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Convert directory to QEMU/KVM virtual disk image
I have a directory filled with data at /var/backups/disk1 that I want to convert into a virtual disk image which I'll then be able to boot using QEMU or KVM (the directory contains the file system for ...
- 131
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1
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KVM gets stuck at "Booting from hard disk"
I am trying to run Ubuntu-server-16.04 virtual machine on a KVM converted from .vhdx (Hyper-V) to .qcow2 (KVM).
When I import my virtual disk image and start virtual machine, the KVM hangs on "...
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5
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Solidworks: activation license mode is not supported in this virtual environment (Qemu-KVM)
The question is not around Solidworks actually, so please continue to read.
The whole idea of virtualization is to be hardware independent. Before our eyes a whole new dependency level is being ...
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5
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How to speed up QEMU on Windows host?
We want to run our Ubuntu 64bit web server virtualized/emulated on a Windows 64bit host. Intended use is to distribute the VM to customers who might not have "elevated" or "admin" rights on the ...
- 131
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1
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Difference between qemu-kvm, qemu-system-x86_64, qemu-x86_64
For new features, I recently updated qemu-kvm 1.5.3 to qemu 2.5.0, but I saw several qemu binaries, /usr/local/bin/qemu-x86_64 and /usr/local/bin/qemu-system-x86_64. It seems qemu-system-x86_64 is the ...
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3
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How to quit QEMU monitor?
I launched KVM VM with this command:
kvm /kvm/hdd/v1/v1-1.raw -m 512 -daemonize -smp 2 -nographic -net nic,model=virtio,macaddr=aa:aa:aa:aa:aa:01 -net tap,ifname=tap0 -monitor telnet:localhost:7001,...
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How to add virtual storage as SSD in KVM
Being previously a VirtualBox user, I moved to KVM(QEMU/libvirt or whatever it's called) recently. I know that in VirtualBox, when you add a new storage device to the VM, there is a checkbox labeled ...
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2
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Backup of running KVM qcow2 VPS
I want a robust method of taking backup of KVM VPS of qcow2 file, while running.
After searching for a long time I found that we can use rsync for live backup.
I used following command for rsync:
...
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11
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3
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WARNING KVM acceleration not available, using 'qemu'
Running debian (Linux Rick 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 (2015-11-09) x86_64 GNU/Linux)
Looking at my cpuinfo I can see I have vmx support:
flags: fpu vme de pse tsc msr pae mce ...
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5
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How can I change Qemu KVM machine architecture from 440fx to q35 with virsh edit or virt-manager
Still trying to get GPU passthrough working and decided to change machine type from older 440fx to q35 ie pc-q35 but if I do virsh edit on the config it refuse to save saying "PCI Bridges not ...
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5
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qemu running in ssh: how to exit?
I am connected via SSH to a terminal server. On this server I am using
qemu-system-x86_64 ... -curses
to run a Command Line based operating system.
How can I terminate the virtual machine?
At the ...
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votes
1
answer
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QEMU and serial ports on the guest OS
Has anyone successfully managed to run a Guest OS in QEMU/KVM where the guest has full access to the Hosts serial port(s), be it /dev/ttyS0, COM1, or a virtual serial port provided by the Host.
It ...
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Changing boot device for a QEMU-KVM virtual machine
I am trying to change the boot device for a VM. I go to the VM's XML file in /etc/libvirt/qemu and set <boot dev='cdrom' />. Still, it attempts to boot from the harddrive instead of the cdrom.
...
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Why can't QEMU allocate the memory if the Linux caches are too big?
If I use my machine [Ubuntu 16.04 64 bit, kernel 4.4] for a while, QEMU needs the kernel caches to be dropped, otherwise, it won't manage to allocate the RAM.
Why does it happen?
This is a sample ...
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4
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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 ...
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votes
2
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QEMU - incorrect real disk size of a virtual drive
df and ls report different sizes on my host machine because of the difference between the allocated size and the amount of space that's actually used in the EXT4 filesystem.
The problem is that both ...
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3
answers
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attaching usb dongle to KVM VM
I'm struggling to connect a usb device, that gets detected correctly by the host, to a kvm vm.
I have a freshly installed Ubuntu Server 14.10 as KVM/QEMU host. I set up an Ubuntu vm using this ...
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votes
1
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Vagrant (Virtualbox) host-only multiple node networking issue
I'm trying to use a multi-VM vagrant environment as a testbed for deploying OpenStack, and I've run into a networking problem with trying to communicate from one VM, to a VM-inside-of-a-VM.
I have ...
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KVM/Qemu, Ubuntu: Why do more guests CPUs enhance Disk-I/O rapidly?
We have an Heartbeat/DRBD/Pacemaker/KVM/Qemu/libvirt cluster consisting of two nodes.
Each node runs Ubuntu 12.04 64 Bit with the following packages/versions:
Kernel 3.2.0-32-generic #51-Ubuntu SMP
...
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9
votes
2
answers
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How to repair a broken-resized qcow2 disk image for libvirt/kvm?
Today I wanted to increase the size of a VM, so I did what I always do (have done it before):
qemu-img resize diskimage.qcow2 +22GB
Then the file broke and the VM does not start any more. I tried ...
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3
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How to forward a port from guest to host in qemu (kvm)
Is it possible, and how, to forward a port from guest to host in qemu/kvm?
Note do I mean (out of) from guest to host, and not from host into guest (that's widely documented).
I think I'm looking ...
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2
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Qemu cannot run Windows 11
When trying to execute the setup the setup stops after selecting the os type with the following result:
"this PC doesn't meet the minimum system requirements to install this version of windows. ...
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votes
3
answers
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Qemu TRIM and discard on a physical SSD device
I am running Windows 7 in a Qemu/KVM with a passed through GPU which I use for work-related stuff. I recently got fed up by it's unprecedented slowness due to it running off a mechanical drive, so I ...
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KVM / QEMU: connect to VM without GUI [closed]
Short Version (Solution is below):
I have a Windows PC.
I have a Debian server (without desktop environment).
I have a Ubuntu VM running on Debian server via KVM/QEMU.
Question:
How can I connect to ...
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votes
1
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Convert qemu syntax to virt-install or virsh xml
I have parameters for qemu-system-x86_64, which attach unix socket as interface into VM:
qemu-system-x86_64
-chardev socket,id=char1,path=/tmp/sock0,server \
-netdev type=vhost-user,id=...
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How to efficiently share host's folder with KVM guests?
I am configuring the service which stores plenty of files uploaded by nginx in /srv/storage dir on host system. These files are processed by worker KVM guests which may create new files or assign ...
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7
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How to "really" reduce the size of KVM VMs images?
I've spent many hours searching the web about how to shrink KVM virtual disk images, especially for Windows guests, with no luck.
All I've found is to zeroize the VM free space, defrag the virtual ...
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3
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QEMU-KVM Linux virtualization on the command line
I recently discovered that qemu-kvm has a very promising -curses option that, instead of starting an X window, will show a nice ncurses output from the guest suitable for managing a Linux guest from ...
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qemu-kvm/virsh: No network connectivity whilst using bridged networking
I'm having an issue with performing virtualisation via libvirt/qemu-kvm, in which my set up for bridged networking doesn't appear to be working correctly. I've followed every tutorial I can find and ...
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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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2
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Monitor VM's resources (CPU, RAM etc)
I'm testing Openstack and i'd like to know how can i find out about resource utilization inside instances (Virtual Machines).
Openstack uses kvm, qemu and libvirt in my testing environment. Is there ...
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2
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Can I run a KVM guest with a btrfs subvolume as file system?
I want to run a virtualized Debian stable KVM guest on a Debian stable host (to run untrusted stuff like Skype, Flash or eclipse with third-party plugins). Naturally host and guest will have many ...
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2
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Filesystem passthrough functionality in Centos 6.2?
I have a CentOS 6.3 machine currently running 2 virtualized CentOS 6.2 machines via KVM/QEMU/Libvirt. I'm trying to setup filesystem passthrough between the guests and the host. However the option is ...
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TCP/IP performance tuning under KVM/Qemu
With more and more companies switching to public cloud services, I'm curious what you guys' thoughts are on TCP/IP tuning in the cloud. Is it worth bothering with? Given that you don't have access to ...
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votes
1
answer
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Prevent hijacking IPs in KVM/libvirt
How can I prevent a VM user/client from accessing IP addresses he doesn't own but are routed over the same bridge on KVM/Libvirt?
IP addresses are routed to a cisco switch vLan consisting of a /24 ...
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votes
2
answers
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Accessing the partitions on an LVM volume
Suppose you have an LVM volume /dev/vg0/mylv. You have presented this as a virtual disk to a virtualised or emulated guest system. During installation the guest system sees it as /dev/sda and ...
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votes
1
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host port forward with qemu through libvirt in user-mode networking
I'm having trouble editing my libvirt's host-xml to make qemu forward TCP connections to the guest. This questions linked to a blog post which recommended adding -redir to the Qemu command line. But ...
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2
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kvm and qemu host: Is there a limit for max CPUs (Ubuntu 10.04)?
Today we encountered a really strange behaviour on two identical kvm and qemu hosts (Dell R910).
The host systems each have 4 x 10 Cores, which means that 40 physical cores are displayed as 80 within ...
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