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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166
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16answers
75k views

Any reason NOT to run Linux in a VM all the time?

I've switched to using Arch Linux for most of my day to day work and don't need Windows for anything but gaming and the couple of apps that aren't ported to Linux like OneNote. My Linux distro is ...
56
votes
3answers
46k views

Does LVM impact performance?

I have to migrate a few servers to Linux, and one important aspect that I need to evaluate is that my new host system must have elastic storage capacity. Naturally, doing some basic research, I came ...
53
votes
11answers
34k views

Easy way to determine virtualization technology

I have command line access to a Linux machine which may or may not be virtualized. I want to determine what kind of virtualization technology it runs on, if any (VMWare, VirtualBox, KVM, OpenVZ, Xen, ...
42
votes
2answers
49k views

How do I run 32-bit programs on a 64-bit Debian/Ubuntu?

I have a 64-bit (amd64 a.k.a. x86_64) Debian or Ubuntu installation. I need to run 32-bit (i386/i686) programs occasionally, or to compile programs for a 32-bit system. How can I do this with a ...
41
votes
10answers
85k views

How to automatically start and shut down VirtualBox machines?

I need to run a software system that is intended to be installed as an appliance on a dedicated machine. In order to save energy, I plan to run the system on a VirtualBox VM instead. The host is a ...
37
votes
6answers
80k views

File permission issues with shared folders under Virtual Box (Ubuntu Guest, Windows Host)

I am using Ubuntu on Virtual Box and I have a folder which is shared between the host (Windows) and the VM (Ubuntu). When I open any file in the share folder in Ubuntu, I can not change it as its ...
33
votes
1answer
21k views

Linux LXC vs FreeBSD jail

Are there any notable differences between LXC (Linux containers) and FreeBSD's jails in terms of security, stability & performance? On first look, both approaches look very similar.
26
votes
7answers
22k views

Should LVM partitions be used in virtual machine images?

Should LVM be used for the partitions when creating VM images (e.g., KVM images)? It seems like it adds complexity if you want to, say, mount a qcow2 image in the host if the image has LVM partitions. ...
24
votes
2answers
3k views

What do the processes inside a Docker container look like?

I've heard confusion come up several times recently around what a Docker container is, and more specifically what's going on inside, with respect to commands & processes that I invoke while inside ...
24
votes
3answers
43k views

VirtualBox: two network interfaces (NAT and host-only ones) in a Debian guest on Ubuntu

I created a Debian VM on VirtualBox with two interfaces: a NAT one (for accessing internet) and a host-only one. However, I do not know how to make both interfaces work at the same time. If I the ...
18
votes
1answer
4k views

how to send CTRL-ALT-Fn to virtual box guest Linux?

This should be a simple question: Host OS: Arch Linux Guest OS: Arch Linux (GNOME) How can I send Ctrl+Alt+F1 to my Guest Linux OS?
17
votes
11answers
17k views

Find out if the OS is running in a virtual environment

Is there any way to find out if the OS I'm running (actually installing) is running in a VMWare machine. I need to disable ntp settings if the automated install is done on a virtual machine but keep ...
17
votes
2answers
1k views

Is developing/testing a linux module safe using a virtual machine?

I'm in an operating systems class. Coming up, we have to do some work modifying kernel code. We have been advised not to use personal machines to test (I suppose this means install it) as we could ...
16
votes
1answer
17k views

Do VirtualBox or VMWare use the Intel VT-d feature?

I'm thinking about a new laptop, which has Intel VT support, but recently I discovered a feature other than Intel® Virtualization Technology (VT-x), which is Intel® Virtualization Technology for ...
15
votes
4answers
8k views

Convert image of a partition into image of a disk with partition table

I have an image of an existing partition generated with dd if=/dev/sdXN of=image.bin. Now I want to use this image as the basis for a virtual machine. I know how to convert the image into a format ...
13
votes
4answers
5k views

Lightweight isolated linux environment

I want an isolated (guest) Linux environment on my computer that I can mess up without worrying about the host. E.g. install a lot of stuff from source without package management, pollute environment ...
13
votes
3answers
2k views

What are benefits and downsides of unprivileged containers?

The technical explanation of what is unprivileged container is quite good. However, it is not for ordinary PC user. Is there a simple answer when and why people should use unpriviliged containers, and ...
12
votes
4answers
7k views

Good distro for a VM?

I want a lightweight Linux VM that I can run with VirtualBox on Windows so I can test how to deploy PHP apps, Mono apps, etc. I don't need the UI and was thinking of going with the Ubuntu server ISO. ...
11
votes
2answers
2k views

Tools for Monitoring Steal Time (st)

We're running on a virtual "dedicated" server, which should, in theory, mean that we're the only guys on the server. In practice.... I'm thinking we might not be. Notice that although it looks ...
11
votes
4answers
13k views

Booting the already installed Windows from the VirtualBox installed in Ubuntu

I want to boot the Windows which is installed in laptop's internal harddisk(/dev/sda1) from the VirtualBox installed in my Ubuntu. Can somebody tell me how to do this in VirtualBox.
11
votes
1answer
6k views

Using a LVM partition as a Virtualbox drive

Is it possible to use a LVM partition as a Virtualbox disk? I can't find any option to use a device as a Virtualbox disk, only disk images.
11
votes
1answer
8k views

ssh-agent forwarding for a Vagrant VM

I'm currently looking at setting up a Vagrant environment on my Mac machine, so that I can run vagrant up and it will then install rbenv and ruby and all I need. Then I have a Bash script that will ...
10
votes
1answer
6k views

Linux - LXC; deploying images with tiniest possible X11

is it currently possible to setup LXC containers with X11 capabilities? I'm looking forward for the lightest available X11 container (memory-wise), hardware acceleration a plus but not essential. If ...
10
votes
2answers
4k views

How can I install a 64bit Linux virtual machine on a 32bit Linux?

I've got a computer (Intel core i5) with 32bit Linux installed (ubuntu 11.04) and I would like to install a 64bit Linux virtual machine on it so I can test 64bit command-line applications on it.
10
votes
3answers
3k views

What's causing VirtualBox OSE to hang my machine?

I'm using VirtualBox OSE and recently, when I run Ubuntu 10.10 on it, my machine tends to hang, forcing me to hard-reset it (not good). How do I start finding where the problem is? Here's the last ...
9
votes
3answers
26k views

“echo 3 > /proc/sys/vm/drop_caches” - Permission denied as root

I am currently having some issues with the cache. It is a little too much right now so I wanted to clear it. I googled and found this little command: sync && echo 3 > ...
9
votes
3answers
476 views

Physically break into box? (Memory & disk)

I have a VPS. I might be able to encrypt my partition but I havent tried. My VPS company I believe can reset my root password although the only SSH key I see is my own. With all my data I have it ...
9
votes
2answers
4k views

Fast X for LXC guest on localhost?

How can I run X apps inside an LXC container efficiently? ssh -Y guest is too slow - there is no graphics acceleration with ssh -Y - everything has to travel over the virtual network with the ...
8
votes
1answer
1k views

How can I remove all my docker images?

Sometimes I just want to clear everything out of docker, and start with a clean slate. Is there a systematic way to just remove all my Docker containers & images? Containers $ docker ps -a | ...
8
votes
1answer
2k views

Does quiesce exist for Linux?

Quiescing a file system allows you to make a backup of the database while it is still running and other programs and their data as well. The application generally needs to be notified of the quiesce ...
8
votes
2answers
7k views

Linux-KVM, QEMU, Virtualbox, VMWare [closed]

I'm new to Linux. I'm trying to build Chromium OS and run it on QEMU. Meanwhile I came across Linux KVM, Virtualbox and VMWare. So I have basically two questions about virtualization in Linux: What ...
8
votes
1answer
806 views

Lightweight virtualization on Linux with user isolation

What Linux-on-Linux virtualization technologies provide user isolation? Specifically, I want root in the virtual machine not to have any privilege on the host. This was not the case for LXC, but was ...
7
votes
3answers
13k views

Which *nix distro is most lightweight for running virtual machines? [closed]

EDIT: This question was expanded to include other Unix-like distros such as Hurd and BSD. Before anyone wonders, I did read related questions and answers; I think I have a sufficiently unique ...
7
votes
2answers
3k views

Is there a convenient small Unix virtual machine I can install as an Android app?

Ubuntu for Android seems to be missing in action. I'm travelling tomorrow and I need to take a basic Linux machine with me. I'd rather just take my tablet than a laptop. So is there a reasonable ...
7
votes
2answers
2k views

What is a Linux container and a Linux hypervisor?

I looked at the stackexchange site but couldn't find anything. I looked at the wikipedia entry on Linux container https://en.wikipedia.org/wiki/LXC and as well as hypervisor ...
7
votes
3answers
36k views

CentOS on HyperV - eth0 not in ifconfig?

I've launched a CentOS install in HyperV and assigned a NIC the same way I've done on an Ubuntu VM, however, the device simply isn't picked up. Only my loopback is found by ifconfig. How should I go ...
7
votes
2answers
5k views

CPU usage of KVM

I have a linux host with 4 KVM linux guests. All the guest are pretty much idle, having a load of <0.1 inside the guest. Now, if I do a top on the host, each KVM process is using something about ...
7
votes
2answers
845 views

Xen/KVM/LXC for testing packages

On Debian Stable, I would like to be able to create a new instance of the OS, use apt-get to install some Unstable packages with dependencies, then cleanly delete the whole thing when I'm done. ...
7
votes
1answer
4k views

docker - how to run x desktop in a container?

I'm trying to set up my Linux machine to run multiple guest OSes, one of those being a Windows VM, and another a Linux container. The goal here is to prevent me from messing up the host system, while ...
7
votes
1answer
340 views

KVM reports strange CPU usage peaks (bash infinite recursion)

On a KVM machine running Fedora 20 I ran ulimit -s unlimited (this removes limit on stack size) and an experimental torturing testing script. All this script does is just infinite recursion: ...
6
votes
6answers
6k views

Install virtual machine as non-root?

Is it possible to install any virtual machine software as non-root user and run it ? Which VM's are possible to be installed with out need of root access ? If it is not possible what would be the ...
6
votes
5answers
28k views

How to improve Windows perfomance when running inside KVM

I use Ubuntu 12.04 64-bit and KVM, my CPU is Core i5 3.3 GHz and I have 8 GB of DDR3 RAM. I run Windows 7 in KVM and it's extremely slow. My co-worker use Debian on the same PC configuration and can ...
6
votes
1answer
2k views

GParted LiveCD fails to start

I have a VM setup in VirtualBox (LinuxMint 17.1). But I'm trying to boot to GParted so I can resize a partition. I'm using gparted-live-0.22.0-2-amd64.iso and it boots correctly. I've tried every ...
6
votes
3answers
2k views

What are the differences between various VM software?

I have only ever used VirtualBox and I would like to know, for example, what could I be missing from other offerings. I have heard of KVM and VMWare and I'm sure there's others. Short of reading ...
6
votes
3answers
214 views

Is it 'possible' to transfer a VM to the metal?

How can one take a VM and make it run on the machine?
6
votes
3answers
4k views

How to create user cgroups with systemd

I use unprivileged lxc containers in Arch Linux. Here are the basic system infos: [chb@conventiont ~]$ uname -a Linux conventiont 3.17.4-Chb #1 SMP PREEMPT Fri Nov 28 12:39:54 UTC 2014 x86_64 ...
6
votes
1answer
21k views

Can't resize a partition using resize2fs

I recently resized the hard drive of a VM from 150 GB to 500 GB in VMWare ESXi. After doing this, I used Gparted to effectively resize the partition of this image. Now all I have to do is to resize ...
6
votes
2answers
3k views

Reading a filesystem from a whole disk image

I ran these commands: VBoxManage clonehd d6b9f0a5-98df-48ca-83c8-91a0809ec349 --format RAW Debian.raw sudo dd if=~/.VirtualBox/HardDisks/Debian.raw of=/dev/sda5 When I try to mount the partition, I ...
6
votes
1answer
4k views

setup kvm on a wireless interface on a laptop machine

I am trying to setup KVM in ubuntu 14.04 host machine. I use a wireless interface to access the internet in my machine. I have setup the wireless interface in my /etc/networks/interfaces as below. ...
6
votes
1answer
2k views

Can VirtualBox return IP address for launched VM?

I would like to start my VM from the command line and without the GUI using the following command: VBoxManage startvm <MY_VM> --type headless and the SSH into it from the next prompt. The ...