Container support under linux relies on built in kernel features - cgroups for limitation and prioritization of resources and namespaces to isolate applications regarding process trees, networking, user IDs and mounted filesystems.
A commonly used abstraction over this functionality is LXC (Linux Containers) which exposes simplified interfaces and libraries. Tools like Docker provide an additional abstraction layer simplifying deployment and management of container units, introducing the concepts of images and tags.
OpenStack provides container support via its compute service called Nova. Drivers exist to create and manage containers both using LXC (with the libvirt driver) and using Docker. In both cases containers are treated as lightweight virtual machines, offering similar isolation to traditional VMs but using the same kernel as the host.
This document provides information about installation, configuration and usage of nova-docker.