LXC is an operating system-level virtualization method for running multiple isolated Linux systems (containers) on a single control host. It is sometimes referred to as “chroot on steroids”.
LXC provides operating system-level virtualization not via a full blown virtual machine, but rather provides a virtual environment that has its own process and network space. LXC relies on the Linux kernel cgroups functionality that became available in version 2.6.29 and is now available in all further kernel distibutions.
Cgroups was developed as part of LXC. It also relies on other kinds of namespace-isolation functionality, which were developed and integrated into the mainline Linux kernel.
LXC is similar to other OS-level virtualization technologies on Linux such as OpenVZ and Linux-VServer, as well as those on other operating systems such as FreeBSD jails. LXC Containers can define various cpu limits, memory limits etc. (In short all parameters that can be set via CGROUPS) to prevent any one container from interfering with all other containers running on the same LXC host.
LXC uses the linux bridge-utils commands to create local VLANs, and attach containers and physical interfaces to them. With containers the physical overhead (ram, swap space, one kernel per VM, plus hypervisor) that is present in virtualization methods is reduced. With containers, one kernel and one virtual memory space is shared between all the containers running on that host.
For a comparison of other Operating System virtualization techniques, see this link
