Questions relating to Linux namespaces, including commands such as: unshare and ip netns. Namespaces support isolation of filesystems, system names, IPC, processes, networks, and users. Closely related to the docker and lxc tags; use those tags instead of this one if you are simply using docker or lxc to implement namespaces.
Old techniques like chroot are focused on filesystem isolation, but with namespaces, the focus is to isolate other OS layers like PIDs, users, IPC, networking, creating a "virtual OS" with a new group of pids, a new set of users, a completely unshared IPC system (semaphores, shared memory etc.), a dedicated network interface and its own hostname.