containers

https://linuxcontainers.org/

"Containers are a form of light weight virtualization where there is a single kernel that is shared by isolated, resource managed groups of processes… each being potentially a different Linux distribution, with its own users and network stack. Containers don’t offer as much flexibility as hardware virtualization (Linux-on-Linux only), but being much lighter weight they offer increased performance, scalibility, and density and are appropriate for many virtualization use cases."

https://stgraber.org/2013/12/20/lxc-1-0-your-first-ubuntu-container/

An Introduction to LXD - https://archive.fosdem.org/2016/schedule/event/lxd/