[rdtsc]

> Docker builds on that, but it's different.

So what is different?

You wrote whole paragraph about what it isn't. But what is it then that make Docker not just LXC (other container) + scripts to manage applications in it. One could presumable still spawn a single application on any OS...

[evol262]

Docker is application containerization.

While Docker is built on top of libcontainer and cgroups (used to be LXC), traditional containers, including LXC and zones, start init and enough services to look like a "normal" system. You can still use rc.local to manage applications if you want to, I guess.

Docker is a build system for containers which run /bin/foo as PID1, with no services, no ssh, and no init (which presents other problems reaping children, handling sigterm, etc). It's containerization for application virtualization.