[GTALUG] Living in Virtual Machines

[William Park]

On Thu, Jul 02, 2015 at 12:09:01PM -0400, Giles Orr wrote:
> I have this idea that's been slowly forming in my head.  I wanted to
> run it by TLUG for opinions to find out if I'm totally crazy or if it
> might work.
> 
> I hope to set up my desktop (and probably my laptop as well) to have a
> Debian stable base OS - about as stripped as I can manage, just X with
> a lightweight window manager (probably OpenBox).  On top of that would
> be VirtualBox, the idea being to run all my applications from virtual
> machines.
> 
> Since I'd have multiple machines accessing the same /home/, I'd want
> NFS.  That could be run by the host OS, but I was thinking about using
> OpenWRT as the NFS server.  But that immediately runs into a

So, /home is in VM as well?  I didn't know VirtualBox can boot
OpenWRT... if it can boot Linux ISO, then I guess it should also boot
OpenWRT ISO file.

> difficulty: it appears that getting the VirtualBox Guest Additions
> running in OpenWRT is (very?) difficult, so I'd probably have to use
> raw partition access.  The problem with that is that if the partition
> is accessed simultaneously by any application on the host OS, you can
> munge the partition.
> 
> I'm also planning on running another OpenWRT instance: this would be
> used for routing, with all the other virtual machines going through it
> to access the outside world.  Among other things, that would mean I
> only have to administer a firewall in one place.  One idea I'm still
> considering is giving full control of the network card to the OpenWRT
> instance and making the host OS go through OpenWRT to get to the
> outside world ...

You can run VirtualBox VM in "Bridged Adapter" network mode.  That will
expose the VMs to the outside.  This means, the VMs will get separate
IPs from external router/modem, just like your host.  VirtualBox has few
other network modes, ie. NAT Network, Internal Network, Host-only
Adapter.

> 
> This could all probably be done with KVM rather than VirtualBox, but I
> prefer VB not only because I'm more familiar with it, but also because
> .VDI disc images can vary in size (Qemu's .qcow2 image format are
> fixed size) and because VirtualBox handles full screen display of OSes
> better (at least once Guest Additions is installed).  I'm happy to
> listen to reasons in favour of KVM.

For "bridge" mode, VirtualBox is much easier.  It's one mouse click.
With QEMU, you have to create bridge, attach interface to it, and run VM
with "helper" to attach its network card to it.  It's about 5 extra
command lines.

If you know those command lines, then it's one script.  So, it's even, I
guess.  :-)

> 
> Other virtual machines would include TinyCore, SliTaz, and Debian
> Stretch.  The latter would probably be my primary OS.  The thought was
> to ssh from the host OS to the guest with X forwarding, and then run a
> launcher from the guest on the host so any applications run from the
> launcher were from the guest.
> 
> Advantages:
> - I get to tinker with multiple OSes (something I enjoy)
> - if I'm about to go to a dubious website, I can clone a virtual
> machine, use it for the dubious visit, then destroy it
> 
> Disadvantages that I've thought of so far:
> - memory usage

Main disadvantage.  2GB for each VMs and host, plus head room.

> - speed reduction

Yes.  Even with 8-core AMD, it just chokes.  Maybe Intel i7 is better.

> - hard drive usage for disk images
> - complexity
> - mounting USB sticks on guests is extremely problematic

I found VirtualBox handles USB much better than QEMU.  But, still, both
are flaky and hangs frequently.

> - playing sound/video from guests through the host is imperfect
> - hard to determine where an application is running from
> 
> I'm sure there are many, many other problems with this idea.  Go to
> town, that's why I'm here.
> 
> -- 
> Giles
> http://www.gilesorr.com/
> gilesorr at gmail.com
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