running VMs from a live environment

[Chris Brannon <chris@the-brannons.com>]

"John G. Heim" <jheim@math.wisc.edu> writes:

> Would you be willing to write a blog or a wiki entry about this for
> the IAVIT web site?  Maybe we could put out a bootable image with most
> of the work already done.

Sure I would.  There really wasn't much to it, so I'll just document it
here.

William grabbed a copy of the Talking Arch CD image, burned it, and
booted it.  Next, we installed the qemu package into the live
environment.  Basically,
pacman -Sy
pacman -S qemu
We were really lucky that it worked, because the packages on the live CD
can get badly out of sync with the packages in the Arch repositories,
especially with respect to shared libraries.
So adding packages to a live environment on the fly isn't really
recommended practice, but if you're brave and desperate, you'll try just about
anything!  If this step had failed, I would have remastered a new image
just for this purpose.  That's pretty easy to do with Talking
Arch.  I'm sure the same applies to Grml.
Anyway, the package got installed to the RAM-based tmpfs.
After that, we executed
qemu -curses -hda /dev/sda -boot c
and listened to some informative boot messages

Here's the problem.  In some situations, qemu -curses doesn't work.
It depends on whether your distribution or installation is set up to use
a standard VGA text console or a frame-buffer based console.  If it's
the latter, then qemu with curses just displays a banner stating that
the system is in graphical mode, and it won't give you any text.
In some cases, I've had to go out of my way to force things not to boot
into a frame buffer console.  At other times, getting the VGA text
console is as easy as passing vga=normal on the kernel command line.
It's also possible to get qemu to redirect a serial port to a listening
TCP/IP or Unix-domain socket.  See the -serial option in the manpage.
So if the system insists on booting into graphical mode, I could always
start a serial console and then talk to it with telnet, netcat, or
socat.

I hope this is enough detail.
Yes, a bootable live environment with the VM packages pre-installed
would be great.  It shouldn't be too hard to get it added to the ones
that people are using.

-- Chris