[peterwwillis]

I agree that people sometimes mismanage services, in that they might assign too many to a single host, or not make them redundant. I don't know if that's so much to do with a "full blown OS" versus just having a lot of hardware and not knowing what to do with it. The reverse is also terrible, when they spin up a new hypervisor-driven VM for every single puny network service.

The simplified model you're talking about is cloud computing. It doesn't matter if your hosts are virtual or not, the point is having an abstraction layer that manages resources for you so the client application doesn't have to care.

Virt comes into play when you're tailoring your servers to your application. Example: Are you really i/o bound? A thousand 1Us with 4 disks each will deliver more iops than a couple dozen beefy VM host machines, and possibly [read: probably] cheaper than a high-performance SAN. Or, do your services just need segregated resources? LXC (or openvz) will provide that regardless of your hardware, so that may be a good fit too.

The adage 'the right tool for the job' refers not to the most expensive tool, or newest, or the most flexible, or the most anything. It's just the tool that fits right. Could you use a crescent wrench to remove lug nuts from your car? Probably. But it's not the right tool.