[GTALUG] Virtualized OSes

D. Hugh Redelmeier hugh at mimosa.com
Wed Apr 22 21:24:48 UTC 2015


| From: Giles Orr <gilesorr at gmail.com>

| I've been using VirtualBox a lot recently, and I've been pretty
| impressed with it - running more than one simultaneous machine,
| setting up an internal network and running ansible between them,
| nifty.

It is a neat trick.

But what is it useful for?

Clearly it is great to be able to run different OSes if you need to
run more than one.  For example, to be able to run MS Word when you
mostly want to run Linux.  Or to test on multiple platforms.

In the Libreswan project, we use virtualization to test networking 
software.  Since some of the code is in the OS, we at least sometimes have 
to run different OSes.

But most of virtualization seems to be for other purposes.

|  Today at work we had an interesting discussion about Digital
| Ocean: the suggestion was made (and undoubtedly it's obvious to many
| on this list, but it was eye-opening to me, I'm still getting my head
| around disposable machines) that if you weren't sure an upgrade to a
| droplet would work, just clone it, do the upgrade on the clone and see
| how it goes.  Then you can make your decision and destroy the unwanted
| version.

Yeah, that (sadly) is a good use case.  But surely a proper package
management system would let you do this too.

- allow more than one version of a package to be installed

- allow more than one instance of the same package, but with different 
  global configuration.  Perhaps global configuration is evil.

- allow package dependencies to contol which versions of each package
  talk to each other.  For example, if A talks to B, under some
  conditions, old A should talk to old B

- make sure that distinct package's configurations don't affect each
  other.  Example: two different packages that use Apache; they should not
  configure Apache in ways that conflict.

- job migration between machines, even while running, seems useful.
  (That's not a package management problem.)

One step more towards virtualization:

Jails are minimal and may be good enough but a lot cheaper than
supporting true virtual x86 machines.

|  All of which made me think "wouldn't it be cool if I could
| have a system with an totally stripped Linux with VirtualBox as the
| "Window Manager" so I could toggle between two or three running OSes
| with graphical interfaces ..."  So:

I think that Serious VMware products are stripped Linux systems that
can run VMs without a lot of extras.

I think that Zen Dom0 (host) can be minimal too.

So much of the noise this day is about things like Docker and CoreOS.
A lot feels like branding exercises rather than technology.  I find it
too hard to figure out what they actually are.


More information about the talk mailing list