Zen and the Art of Multiplicity Maintenance: An applied survey of BSD-licensed multiplicity strategies from chroot to mult.

Michael Dexter

Many BSD-licensed strategies of various levels of maturity exist to implement multiplicity, herein defined as the introduction of plurality to traditionally singular computing environments via isolation, virtualization, or other method. For example, the chroot utility introduces an additional isolated root execution environment within that of the host; or an emulator provides highly-isolated virtual systems that can run complete native or foreign operating systems. Motivations for multiplicity vary, but a demonstrable desire exists for users to ¿obtain root¿ or run a foreign binary or operating system. We propose a hands-on survey of portable and integrated BSD-licensed multiplicity strategies applicable to the FreeBSD, OpenBSD, DragonFlyBSD and NetBSD operating systems on the i386 architecture. We will also address three oft-coupled disciplines: software storage devices, the installation of operating system and userlands in multiplicity environments plus the management of select multiplicity environments. Finally we will comment on each strategies¿ potential limits of isolation, compatibility, independence and potential overhead in comparison to traditional systems. Keywords: multiplicity, virtualization, chroot, jail, hypervisor, xen, compat.
Michael Dexter has used Unix systems since 1991 and BSD-licensed multiplicity strategies for over five years. He is the Program Manager at the BSD Fund and Project Manager of the BSD.lv Project.