On 08/29/2016 10:07 AM, Lennart Sorensen via talk wrote:
On Fri, Aug 26, 2016 at 09:33:50PM -0400, William Park via talk wrote:

- QEMU and VirtualBox.  They both use KVM.

Virtualbox does not use kvm.  It will use vt-x if you have it.
kvm requires it.
Its kind of the other way around.
Virtualbox uses QEMU as does Xen and I am sure it appears in some form with other virtualization platforms.
QEMU is the go-to source for hardware emulation.



- VirtualBox practically needs no manual.  It's all mouse clicks.  The
  only time I actually had to read something, was to convert VMDK to VDI
  format (using VBoxManage on command line in Windows)
- QEMU requires manpage and shell script to store all the options you
  discovered. :-)

But the flexibility is great.
Virtual-box is more akin to libvirt in that its a hypervisor management tool.

Virtual-box gives a lot of flexibility if you want dig under the covers and use the command line interface.
But its ugly.
Libvirt has the advantage that it will interface with multiple back-end hypervisors.

Using QEMU directly gives more flexibility because you have to manage most of the system plumbing tasks on your own.
Virtual-box and libvirt help you manage those tasks but  make some implementation choices that you may or may not like.




I'm not sure about "headless".  From memory, I seems to have closer
association with VirtualBox than with QEMU.

qemu's ability to run as a vnc server is handy.
I know libvirt allows for a serial console so that there is no need for a graphical and I have used that quite a bit because I often found myself at the end of a low bandwidth connection where running VNC was just too painful to be believed.
I am sure Virtual-box has the same feature but I have never used it.

In general Virtual-box is easier to install and works well for running up a hand full of virtual machines.
Virtual-box seems to make better default choices for performance and gives better emulation of things like USB interfaces.
It also does a reasonable job at simple network plumbing and importing and exporting of disk images.

Virtual-manager is somewhat like Vritual-box and is part of the libvirt suite of tools.
It is more generic and allows you to manage several virtualization servers along with different hypervisors.
It does a reasonable job at network plumbing but its hardware emulation is only as good as the mainline QEMU support, and the Oracle folks are able to pay to get access to proprietary information about hardware making their emulation a bit better.
The libvirt development tends to track the KVM/QEMU develpment so just about every feature that is available directly in QEMU can be found in libvirt.

The above tools are good for straight forward flat networks but if you require complex network plumbing like NAT interfaces and simple firewalls and multiple isolated networks then your are getting out of the range of the simple virtualization managers and are looking more at something like Openstack and its competitors.

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