I’m always looking for ways to explain virtualization to the nontechnical people in my life, and just came across a really good analogy, courtesy of Luke Kanies, the author of Puppet system administration tool:
A virtual machine is to the host as an egg is to the carton.
Actually, this is what Kanies really said:
The truth is that [VM] images make a lot of things a lot easier, but when it all comes down to it, VMWare is great for managing the outside of a box. I’ve been told this is a horrible analogy, but the way I think of it is, all of these virtual machine systems — they’re really good at producing and managing eggs, you know these self contained, sealed eggs of functionality. But they’re not very good about getting inside the system. They can’t get inside the egg and manage what’s going on there.
That’s so true. For now, VMware doesn’t do anything to help you get at the whites (the OS) or the yolk (the application), to say nothing of the yucky membrane between the two.
Much like egg cartons and their contents, virtualization doesn’t discriminate on the basis of color: You can have brown eggs (Linux), white eggs (Windows), green eggs (Solaris) — but you can’t have ham. Nor can you have ostrich eggs (z/OS) or goose eggs (Unix) — they just wouldn’t fit in the carton.
I also like this analogy because of the implicit 12:1 egg-to-carton consolidation ratio. Although, from what I’ve been hearing, most folks have graduated from regular cartons and moved on to those scary 5X6 trays.
Props to the Lone (not Lonely) Sysadmin, Bob Plankers, for pointing out this article and who, incidentally, really likes Puppet.