Questions tagged [virtual-machine]

A virtual machine (VM) is a guest Operating System running in a completely isolated environment within a normal host operating system. Modern virtual machines are implemented with either software emulation or hardware virtualization or (in most cases) both together.

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performance comparison of e1000 and virtio-pci drivers

I made a following setup to compare a performance of virtio-pci and e1000 drivers: I expected to see much higher throughput in case of virtio-pci compared to e1000, but they performed identically. ...
6
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1answer
991 views

virNetSocketReadWire:1801 : End of file while reading data: Input/output error

Every time I start/stop a KVM, the libvirtd 3.0.0-4 throws the following error in syslog: libvirtd[3145]: 2018-08-07 21:00:19.699+0000: 3145: \ error : qemuMonitorIO:710 : internal error: \ ...
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652 views

Setting umask of libvirt/virt-manager for proper permissions in a directory shared by host and guest

I'm attempting to create a directory that is fully available to both the host and guest systems of a virt-manager/libvirt/QEMU/KVM virtual machine, with read, write and execute permissions for non-...
5
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795 views

Virtualization (KVM) and excessive cached RAM

I've set up a virtual machine through KVM-libvirt (virt-manager) with Windows 10 on it and I'm getting an odd behavior on the host side. I'm running a 64bit Arch host with 24GB of RAM, 12 of which are ...
4
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0answers
434 views

How do I actually make use of the kvm-clock clock driver?

According to copious sources, the KVM clock driver is loaded as shown here: cat /sys/devices/system/clocksource/clocksource0/current_clocksource These sources all seem to think that this ...
4
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0answers
828 views

perf cycles not supported

I am trying to use perf for profiling in a Linux virtual machine. However, I am receiving the following output: [vagrant@localhost ~]$ perf stat -d ls / bin boot dev etc home lib lib64 lost+...
4
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1answer
146 views

Disable buffering in a VM configuration

I am executing some benchmark using a DBMS and virtual machines. And I am using this command free && sync && echo 3 > /proc/sys/vm/drop_caches && free on each Guest, and ...
4
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0answers
224 views

sharing folders in virtual box

I'm trying to run a Linux Mint guest inside a Linux Mint host(both 64-bit). I've installed Guest Additions etc. But I'm not able to access the shared folder. sudo mount -t vboxsf kernel /media/...
4
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0answers
5k views

In virtual machine manager, is there a way to add disk space to an existing disk?

I know that in virt-manager you can add RAM and processors to the virtual machine, but is there a way to increase the available disk space larger through the GUI? Edit: @slm was able to find the ...
4
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1answer
432 views

On Linux, (how) can I “hot-unplug” memory?

This is what I've tried: sudo zsh -c 'echo offline >/sys/devices/system/memory/memory109/state'` and got the following error: zsh:echo:1: write error: device or resource busy Do I perhaps need ...
3
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1answer
386 views

How to route traffic through VPN only accessible within VM (without a bridged adapter)?

I have an interesting situation where I have a corporate VPN that can only connect through a specific (outdated) version of Ubuntu (and/or Windows) using a vendor-supplied client that creates a VPN ...
3
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1answer
150 views

How to convert root filesystem to virtual disk format (img, vmdk or vdi)?

I unpacked the contents of a Mageia 6 ISO image, including a Linux root file system in it, and I've updated the root file system by chrooting into it and running dnf update. I also installed a few ...
3
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0answers
170 views

FreeBSD/OVS equivalent of ESXi vSwitch VLAN config

I'm trying out FreeBSD with bhyve hypervisor and trying to replicate VMware ESXi vSwitch config in FreeBSD so that pfSense VM gets network traffic properly. VLANs: 111 = LAN, 192.168.101.0/24 333 = ...
3
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0answers
334 views

KVM passthrough in virtual machine more than 3 usb devices

I have a question, how can i passthrough in virtual machine more than 3 usb devices? I have a usb hub and i cannot passthrough in virtual machine more than 3 usb device. My usb device connect to usb ...
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0answers
1k views

AMD-Vi: Unable to write to IOMMU perf counter. Arch Linux

I'm having some problems with an Antergos 4.18 installation on my Acer Swift 3 (SF315-41) the main one is regarding virtualization. At first when I booted up the OS I would get this messages: [...
3
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1answer
803 views

QEMU Guest using huge amounts of compressed memory on boot

Virt Manager configuration: Guest memory usage right after booting (nothing is running): I'm running virt-manager on a standard Ubuntu 17.10 system. In Proxmox, the same general configuration (with ...
3
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0answers
56 views

How is the cgroup user UID of a container's user allocated?

I use containers (systemd-nspawn but I believe lxc will be similar) and from the perspective of the host, users in containers (including root) have specific UIDs, such as 3804364+. Are these IDs ...
3
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0answers
106 views

how to update the firmware of an epson xp 211 printer in linux?

Since the epson utility are available for windows and mac, I was wondering how to update the firmware in Linux. Comment> Using a virtualized windows/mac machine would work?. I remembered , this was ...
3
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0answers
1k views

How to define multiple routes for KVM guests with CentOS 7

The code below generates two CentOS 7 GUEST virtual machines on a CentOS 7 HOST. One of the virtual machines is connected to the internet via a PUBLIC IP address. The other is given a PRIVATE IP ...
3
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0answers
328 views

KVM/QEMU hot-replace raw disk

One of VM disks got damaged and I'm trying to replace it online, without rebooting VM. However when I use: drive_add virtio1 file=/dev/sdb,format=raw,if=virtio,cache=none,aio=native in VM monitor ...
3
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0answers
540 views

*REAL* zerofree equivalent for btrfs

is there any zerofree equivalent for btrfs ? and please don't give me sfill or cat /dev/zero >/tmp/file, this is not the same thing at all, be cause Zerofree finds the unallocated, non-zeroed blocks, ...
3
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0answers
85 views

Why does bash appear faster on an Ubuntu VM than on the host MacOS?

This is the laptop sitting in front of me right now: On it is installed VMWare Fusion 8.5.3 with an Ubuntu 16.04 64 bit VM. I ran the following little test to compare performance between bash on the ...
3
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0answers
289 views

Logitech controller not passing into Centos virtual machine as joystick

I have a Logitech Dual Action Controller that I am trying to use in a Centos virtual machine (using VirtualBox). The controller is in "D" mode (according to the switch on the back of the controller) ...
3
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0answers
225 views

How to tell virsh: save state of VM and vdisk, but not attached disk?

I installed a fresh CentOS 7.2 guest (babybrighton) on my host (brighton), and then did this from brighton (where /dev/sdb is a physical device connected to brighton): virsh attach-disk --...
3
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2answers
343 views

Verifying IO bottleneck

We are working on a project to benchmark systems in virtual machines that share the same physical host. I think we have a bottleneck with the system hosting the virtual machines, which may ...
3
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0answers
5k views

Libvirt qemu changing hardware identifiers?

I am having a strange problem that I just cannot figure out. I have a Windows 7 virtual machine that was originally a physical machine that was demoted to a VM awhile ago. I used to boot it with ...
3
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1answer
567 views

Getting a Windows 7 installation to run virtualized under Ubuntu?

I've currently installed Windows 7 and Ubuntu via dualboot. To avoid switching the OS by rebooting, i want to be able to start my Windows 7 via a virtual machine. It is important to be able to boot ...
3
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0answers
1k views

Virtualbox and GPU Pass-trough: Device with host PCI address already attached to this VM

I have server with several GPUs. My idea is to attach them to different VMs in order to use that VMs in CUDA (or OpenCL) calculations. My setup: CPU: Intel Xeon E5-2670 GPUs: 1 x Radeon HD 7970 $ ...
3
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1answer
506 views

Iptables rule to drop packets to and from local network

I want to set a virtual machine on laptop, but I don't trust the guest system fully, so I would like to block it's access to local network (to network 192.168.0.1/16 or 10.0.0.1/8 or ... the other one ...
3
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0answers
934 views

Running Mac OS X under KVM/QEMU

Note to be removed in the future, so as to avoid confusion from answerers and mods edit: Forgot to add in the note, if anyone thinks this is the wrong stack-site to post this, please comment on why, ...
3
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1answer
631 views

Arch Linux openSSH frequently drops connection

I'm running a VM using Oracle's VirtualBox. The OS is the latest version of Arch, 64-bit. For some odd reason, every so often (frequently enough to be very annoying and making it almost impossible ...
3
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0answers
957 views

Network connectivity issue between different hosts from a network namespace in one host

I have created two Ubuntu 12.04 VMs using VMWare Player with NAT network configuration. I am able to ping them from each other. After that, I created a network namespace in one of them and add a ...
2
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0answers
51 views

Unable to successfully setup bridge interface with Netplan, in order to support guest OS with KVM

First of all, I would like to apologize for my bad English. I usually find an answer after a few hours, days or even weeks of research, but today, I feel quite lost and would appreciate some help. ...
2
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0answers
17 views

Second video card for virtual machine with PCI passthrough

I am very new to the PCI passthrough topic. So could you explain some things to me. I have a System with Ryzen 5 1600 and GTX 1060 6GB. I also have a secondary PCIe slot and an old Radeon HD 5700. So ...
2
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0answers
37 views

What virtualization platform does provide dynamic memory allocation?

I need a virtualization platform for Linux host that supports Dynamic Memory Allocation. By Dynamic Memory Allocation I don't mean Memory Ballooning where we can request memory from a running VM (...
2
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0answers
72 views

Compress VirtualBox Linux Virtual Machine

I am trying to create a VirtualBox linux virtual machine on which I want to mainly run Wine to install a windows application. I managed to install Lubuntu 18.04.2, since it is the lightest Ubuntu ...
2
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0answers
188 views

VMware Workstation guests NAT adapters always got the same IP address

I'm on Windows and created three Ubuntu 18.04 Desktop virtual machines using VMware Workstation. This is my NAT and custom host-only network configuration. This is my guest VM's network adapters. As ...
2
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1answer
386 views

Linux Mint on Virtual Box Display Bug

I've run into a small problem when I launch Linux Mint on Virtual Box. During bootup everything seems to be fine. Linux mint logo appears and counts down from 9 until automatic boot, during boot 2nd ...
2
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0answers
37 views

Whether I can use ipmitool in the VM?

When I start the ipmi_si module: modprobe ipmi_si there gets error: FATAL: Error inserting ipmi_si (/lib/modules/2.6.32-696.el6.x86_64/kernel/drivers/char/ipmi/ipmi_si. My environment is a ...
2
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0answers
270 views

QEMU crashed while trying to boot up i.MX6q device kernel

When tried to boot up Kernel uImage of an i.MX6q based embedded device, it seems that QEMU crashes with "Unable to handle kernel NULL pointer dereference at virtual address 00000044". Before crashing ...
2
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0answers
373 views

KVM Windows guest battery

I've installed KVM on a laptop with Debian 9. The guest is the latest Windows 10 (1803) with all updates and VirtIO drivers installed. The issue is : Windows doesn't know he's on a laptop. Then, I ...
2
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0answers
492 views

Rename qcow2 internal snapshots created with virsh snapshot-create-as

Background I have a QEMU/KVM virtual machine whose virtual disk is a qcow2 file. To create snapshots, I have been using sudo virsh snapshot-create-as <vm_name> <snapshot_name> and now I ...
2
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0answers
565 views

Parrot OS: “Failed to start Light Display Manager”

i have recently installed Parrot OS on virtualBox, the installation was successful but as the system started booting, it stopped showing "Failed to start Light Display Manager". here is the systemctl ...
2
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1answer
3k views

High CPU usage when KVM Windows guest plays audio

I'm running a Windows 10 virtual machine as my daily driver, it's running on top of ubuntu server 16.04. GPU and USB expansion card passthrough works just fine but I'm experiencing maxed out host CPU (...
2
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0answers
140 views

Use a virtual machines network adapter as hosts default network adapter

Objective: Use a virtual machine network adapter as host's default network adapter. I am looking for advice on how to set this up correctly. The purpose is to have my wireless interface (which ...
2
votes
1answer
2k views

How do I assign static IPs for HOST, BRIDGE, and GUEST

I am learning networking by building a small virtual network within a CentOS host. I need some guidance at the highest level to start planning: The Scenario: A CentOS 7 HOST needs to have a ...
2
votes
0answers
30 views

grub - advance to the next drive

I've got /dev/sda and /dev/sdb, each with it's own MBR on a virtualized Linux server environment. I'd like to instruct grub on /dev/sda while booting to skip "self" and proceed booting off of /dev/...
2
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0answers
71 views

Can't use provisioned space on thin virtual disk

I have this issue with my virtualized RHEL 7.1. I created this VM with thin-provisioned disk. I thought that I know how it should work - provisioned space would be available to the VM, but as long as ...
2
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0answers
902 views

Allow host to ssh into QEMU guest but disable all other networking

I want to run a virtual machine using QEMU and KVM on my Arch Linux host with a configuration such that I can ssh into the guest OS from my host, but I want to prevent the guest OS from being able to ...