Goals
FreeBSD jails mainly aim at three goals:
- Virtualization: Each jail is a virtual environment running on the host machine with its own files, processes, user and superuser accounts. From within a jailed process, the environment is (almost) indistinguishable from a real system.
- Security: Each jail is sealed from the others, thus providing an additional level of security.
- Ease of delegation: The limited scope of a jail allows system administrators to delegate several tasks which require superuser access without handing out complete control over the system.
Unlike common chroot jail, which restricts processes to a particular view of the filesystem, the FreeBSD jail mechanism restrict what a process in a jail can do in relation to the rest of the system. In effect, jailed processes are sandboxed. They are bound to specific IP addresses, and a jailed process cannot access to divert or routing sockets. Raw sockets are also disabled by default, but may be enabled by setting the security.jail.allow_raw_sockets sysctl option. Additionally, interaction between processes that are not running in the same jail is restricted.
The jail(8) utility and jail(2) system call first appeared in FreeBSD 4.0. New utilities (for example jls(8) to list jails) and system calls (for example jail_attach(2) to attach a new process to a jail) that render jail management much easier were added in FreeBSD 5.1. The jail subsystem has been significantly updated for FreeBSD 7.2, including support for multiple IPv4 and IPv6 addresses per jail and support for binding jails to specific CPUs.
Read more about this topic: Free BSD Jail
Famous quotes containing the word goals:
“I think that any woman who sets goals for herself and takes her own life seriously and moves to achieve the goals that she wants as a person in her own right is a feminist.”
—Frances Kuehn (b. 1943)
“Let us beware of saying there are laws in nature. There are only necessities: there is no one to command, no one to obey, no one to transgress. When you realize there are no goals or objectives, then you realize, too, that there is no chance: for only in a world of objectives does the word “chance” have any meaning.”
—Friedrich Nietzsche (1844–1900)
“We should stop looking to law to provide the final answer.... Law cannot save us from ourselves.... We have to go out and try to accomplish our goals and resolve disagreements by doing what we think is right. That energy and resourcefulness, not millions of legal cubicles, is what was great about America. Let judgment and personal conviction be important again.”
—Philip K. Howard, U.S. lawyer. The Death of Common Sense: How Law Is Suffocating America, pp. 186-87, Random House (1994)