A matryoshka doll is a set of dolls of decreasing sizes placed one inside the other. Virtualization is a concept similar to the Matryoshka analogy. There is another system running inside the host machine. So it is box in a box. Each performs and executes exactly like a stand-alone server; a container can be rebooted independently and have root access, users, IP addresses, memory, processes, files, applications, system libraries and configuration files.

The container technology aka LXC is actively being pushed into the mainstream linux kernel. It provides the resource management through the control groups aka process containers and resource isolation through the namespaces.

LXC is interesting primarily in that:

• It can be used to run a mere application, service, or a full operating system.
• It offers essentially native performance. A binary running as an LXC guest is actually running as a normal process directly in the host os kernel just like any other process. In particular this means that cpu and i/o scheduling are a lot more fair and tunable, and you get native disk i/o performance which you can not have with real virtualization (even Xen, even in paravirt mode) This means you can containerize disk i/o heavy database apps. It also means that you can only run binaries that the host kernel can execute. (ie: you can run Linux binaries, not another OS like Solaris or Windows).