linux KVM vs virtual box

willc86 · 05-08-2015, 11:28 PM

hey guys

ive been reading about KVM and VB. i already researched that KVM is lighter and also performs a lot better

however, one question that I have, that I was not able to find yet, is, when you run an image on KVM, does it open up a window like virtual box; or does it just open up as a process, and I can remote desk into it? if were to open all 4 images in virtual box, it will definitely be heavy for my server. ( giving 2 rams for each server) so would KVM be a better choice?

and when people say light; how is KVM lighter than virtualbox if they still use the amount of ram you specify?

my goal is to virtualize everything and be able to rdesktop into a DNS server, DHCP server, and windows active directory. I know I can also get this done with virtualbox, but I heard KVM is more reliable and not so heavy on your virtual server.

a perfect example would be, if I had KVM, and I opened up all 4 virtual OS @ 2 gigs, it will still be using 8 gb of ram just like virtualbox, correct? I will still have the virtual interface popping out just like virtual box, or everything is strictly running through the command line and/or kernel?

John VV · 05-08-2015, 11:41 PM

it really depends on what one is doing and what they need

VB is good for somethings
and KVM is great at some things

use what is best for your needs and if KVM is default

RHEL and SUSE have kvm in the repos
for suse it is easy

Code:

su -
zypper in patterns-openSUSE-kvm_server
----- or ----
zypper in kvm_server qemu-kvm

i have Debian8 running using a qcow container in kvm
now i only have one 3d card so no 3d card passthrough
but for what i use Debain8 for this is fine

Quote:

hat I was not able to find yet, is, when you run an image on KVM, does it open up a window like virtual box;

a window opens
dedian 8 boots ( full drive encryption ) so during the boot i type in the passphrase

then i log into debian 8

all this is on top of Dolphin open to my suse home folder or with firefox running

like now as i type

willc86 · 05-09-2015, 09:12 AM

thanks for the reply buddy!

what would be best for leaving all the virtual servers on without having too much stress on the server? and also which would you say is more reliable? less likeley to fail or come up with an error of some sort out of nowhere

sundialsvcs · 05-09-2015, 09:29 AM

Both of these are reliable, well-tested technologies that are in widespread use. The "stress on the server" will come from the guest machines, not from the hypervisor. As always, be sure that you are running VM's using microprocessors of recent vintage, thus with the most up-to-date hardware support for virtualization.

willc86 · 05-11-2015, 02:01 PM

So, in other words, to have 4 VMs constantly running, either or would get the job done, correct?

the 4 VMS i am planning on keeping up 24/7 are

-DNS server
-fog server
-windows active directory
-virtual web server
-and maybe a DHCP server

jefro · 05-11-2015, 05:26 PM

Both the two replies to your question are in line with most people's views and good replies.

There are some fine points that could sway one over the other but it really boils down to your choice. Both are good and both should work.

The better your hardware is supporting vm's the more likely it will consume less resources.

Samsonite2010 · 05-11-2015, 05:49 PM

One thing to point out with Virtualbox is that you can run it in headless mode and even from a command line / terminal to reduce resource usage which I think makes it pretty lightweight. One thing I found VB best for was setting up virtual networks easily so having a Domain controller, SQL server, Web server, etc. The other feature that I like is that hardware acceleration and guest add-ons create a very fast and slick experience within the guest itself - better than any other VM technology out there - for many this is not important, but I found it useful for running software like Visual Studio and doing software development.

sundialsvcs · 05-12-2015, 08:33 AM

Most VMs are "headless." You usually don't need a graphic user-interface running alongside them, slurping up cycles to draw pretty pictures. Instead, if you need to control them, you connect to them through a socket interface.

The software is often called a hypervisor, in the same way that an operating-system is often called a supervisor. The CPU hardware provides support for virtualization, and the hypervisor does the VM-switching. The hypervisor is also responsible for brokering some (but not all) of the I/O requests that are issued by any of the guests. (For instance, if you map "a hard drive" to a physical "file," the hypervisor is the one doing the I/O to the file and interacting with the host filesystem.)

Looking at your requirement, it superficially seems to me that one VM-image might well be able to handle all four-or-five roles. You don't need to be doing KVM-context switches unnecessarily. Just let the hypervisor run one VM which, in turn, runs a slew of processes and daemons.

willc86 · 05-12-2015, 12:51 PM

so it seems virtualbox might be a better choice for me.

when you say headless, you mean no window pop up correct? just a backbone program running?

Samsonite2010 · 05-12-2015, 04:59 PM

Quote:

Originally Posted by willc86

so it seems virtualbox might be a better choice for me.

when you say headless, you mean no window pop up correct? just a backbone program running?

Indeed, I set my VB VMs up using the GUI - makes life easier, then I set a shortcut to a headless command line to fire up the VM with no front-end for ongoing use. Then I remotely connect to the VM(s).

jefro · 05-13-2015, 05:19 PM

I'd think that many users start on windows and have vmplayer or vmware workstation or virtualbox running so they already know those type of apps.

KVM has front ends to make it more easy to run and configure.

All of them I think can be run without any pop-up window and allow access via either HTTP web or a type of vnc or ssh.