Virtual Machines
 

Nowadays several ways of creating virtual machines exist:
- KVM
- VirtualBox
- VMWare
- ... (there's probably a few more)

In the past I used VirtualBox with pleasure, but one thing that I found it somewhat lacking in was performance, but mostly in capabilities. KVM is not known as the most easy to install (hey, challenge!) and is reported as being very fast performance as well as getting different architectures emulated and moving nodes... some nice stuff I'd like to experiment with.

All in all, things sound interesting... the question remains: is it interesting enough? People who can speak from experience for a nice comparison? Apart from the website some good reading fodder on how to get things working?

In many different contexts, for many different reasons, "Virtualization" can be the greatest thing since sliced bread.

I happen to use VMWare the most and, in general, I have nothing but good things to say about VMWare. VMWare/Workstation, Player, Server and, of course, ESX. But I'm sure the same can be said by others of VBox, Xen and, heck, perhaps even of MS Virtual PC and/or MS Hypervisor.

If you only need one PC running one OS - great. That probably defines most needs for most people - and that's fine. But if you need to frequently juggle multiple PC's and multiple OS's; if you're in a lab environment of any kind (development, Q/C or educational) ... then VM's are indispensable.

IMHO .. PSM

I started with VMWare but switched to KVM. The KVM and virtio modules are included with the Slackware distribution. Make sure your CPU and motherboard can support virulization with KVM. Compiling the QEMU-KVM emulator is not a big deal. Learning the startup options is the toughest part

Right after a hot cup of coffee, virtualization is the best invention, right before sliced bread ;-)

Ye, I forgot Xen and the MS solutions, and more probably exist while we're not even aware of them, just like aliens. Especially when I build packages for redistribution, I prefer to do that on a "dedicated", clean system and a VM is the answer. Generally, now that my Slack is 64-bit, I am now capable of making 64-bit packages as well as 32 in 2 VMs.

In a more professional direction, I think -apart from VMWare- KVM offers the most due to machines being able to be moved among nodes to allow the hardware to be maintained without downtime. VMWare offers that as well, I am aware of that. In that area I would like to investigate a bit more, to get some 1st-hand experience on it... the road may be hard, but I guess it's a very interesting road to walk.

Ah, here I go stumbling already (while it's bedtime already...)

root@slacker ~# modprobe virtio
root@slacker ~# modprobe kvm-amd
FATAL: Error inserting kvm_amd (/lib/modules/2.6.29.6/kernel/arch/x86/kvm/kvm-amd.ko): Operation not supported

root@slacker:~# cat /proc/cpuinfo
... snip ...
model name : AMD Phenom(tm) 9550 Quad-Core Processor
... snip ...
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc pni monitor cx16 lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs
... end snip ...

it has the vme flag, so it should support virtualization... this defenitely needs a cup of coffee to dive into I suppose ;-)

EDIT: never mind, I was stupid and didn't put BIOS virtualization on, while I could've sworn I had done that ages ago...

I purchased VMware Workstation for Windows, been really happy with it, till I decided to make Linux my primary OS. I've been debating between VMWare Server and virtual box on Slackware 13 64bit. So far I have not installed either.

Any thoughts on which one is better than the other for Slackware 13 64 bit?

-JJ

I`ve installed VirtualBox a few weeks ago and i have to say i`m impressed. Really comes in handy if you are like a developer or something and really need to use those M$ only tools. The idea of running 2 OS`s simultaneous is just wonderful.

I started with VMWare, which is quite nice, and feature rich. Got tired of looking for kernel patches each time I updated. VMWare is not universal, and only works with a certain feature set out of the box. If you run one of their supported OS flavors, VMWare is a piece of cake. It's easy to see why most people consider them top dog in the virt marketplace.

VirtualBox is easy to install, easy to use. Decent amount of features, performance limited, and with recent releases, somewhat buggy. I've always had issues with remote VNC, audio flakes out now and then. It's not difficult to find the magic switch combination to crash VBox. 2.4.x seemed to be quite a bit more stable than most releases of this year.

KVM is easier to install than VMWare on Slackware (./configure;make;make install). Has more features than Virtual Box, completely stable. A bit more difficult to use at first compared to the other 2 choices. I notice a huge speed difference between KVM and VirtualBox. Even if your CPU does not support hardware virtualization, you can still use Qemu with the kqemu accelerated module. It does make a difference :)

KVM will be receiving (IMO) the most efforts on Linux hosts going forward. It is stable, and part of the kernel. Red Hat seems to really like this project, and commits quite a bit of time to refining it's code.

I've never bench marked my VMs against each other. But in my view, in terms of pure speed they rank like this. 1.VMWare 2.KVM 3.VirtualBox.

It's the svm flag for AMD, vmx for Intel.

only shows it really was bedtime ;-) But the svm flag was there too, so it worked... ;-) Now either run a vm by hand or try to get some nice gui for it, things seem to be easier than I thought at first. ;-)

Been trying today to give virt-manager a shot, but the list of dependencies, dependencies of dependencies and their dependencies is getting quite long. Not sure if I'm up for a whole long chain of dependencies, when where one thing fails to install properly all the work was just to kill some time...

Got a few days of playing with the virtual machines now, and indeed it is pretty easy to setup; especially if you have a gui that can give show the parameters. That way the fiddling took much less time ;-) I got a nicely performing virtual machine now, just missing one part: video. I can boot 1024x768, but when going to X it manages only 800x600, which is a pity and pretty slow besides.

Through a bit obscure tunneling I could get 2 virtual machines connect to each other, but I think this is not the ideal world... so got to dive into that world yet.
Anyone here with some experience getting VirtualBox images converted into qcow2 images? There used to be a tool with VirtualBox called 'vditool', but they dropped that some versions ago, so I doubt getting a legacy version of that would be able to read the images I got. Is KVM somehow able to handle these?

About 800x600 with KVM. Xorg uses EDID to get the monitor timings. This limits the resolution with the Cirrus video adapter. Edit/create your xorg.conf (the vm's xorg.conf ;) )

Section "Monitor"
Identifier "Monitor0"
HorizSync 20.0 - 50.0
VertRefresh 40.0 - 80.0
End Section

The links I've found say to use vditool to convert to raw then use the qemu-img to convert the raw to qcow2.

example: http://tuxtraining.com/2009/05/09/co...ox-vdi-to-qemu

Thanks Disturbed1, I'll try that out!

There's the issue: vditool "no longer exists", so I would have to grab an old VB somewhere from the interwebs, cross my fingers and hope it can read and convert my images. I was hoping for a more certain approach.

http://blog.bodhizazen.net/linux/con...i-to-kvm-qcow/

It says to use the VBoxManage clonehd command instead.