Comments on: OS Virtualization on FreeBSD vs. Linux

By: dennyhalim

dennyhalim — Sun, 30 Dec 2007 17:52:01 +0000

can we run linux inside freebsd jail??? or different bsd like netbsd/openbsd/etc…???

with openvz (similar, os level virtualization), we can run any other linux inside.

By: Administrator

Administrator — Fri, 10 Aug 2007 06:44:14 +0000

Wow, you FreeBSD users sure are vocal! I’ll have to post some more on BSD I guess.

Thanks for the tips.

By: Dave P

Dave P — Fri, 03 Aug 2007 13:34:21 +0000

It looks like you have a typo, the wikipedia page you linked to says jail was introduced back in FreeBSD 4.0 (backed up by the man page for jail at http://www.freebsd.org/cgi/man.cgi?query=jail)

By: Jeremie Le Hen

Jeremie Le Hen — Fri, 03 Aug 2007 08:45:30 +0000

Hi,

Actually a jailed daemon can listen on 0.0.0.0; the kernel will simply remap it to the jail’s IP address.

One point which is worth mentioning as well is that the FreeBSD handbook provides a complete chapter about jails.

Regards,
– Jeremie

By: Chris Buechler

Chris Buechler — Fri, 03 Aug 2007 01:49:06 +0000

One small correction – it’s been built in since FreeBSD 4.0, not 5.0.

I’ve been using jails for heavily trafficked production servers for years, it’s an awesome solution.

By: Vivek Khera

Vivek Khera — Thu, 02 Aug 2007 03:42:09 +0000

Hi James, that must have been me you’re referring to…

Yeah, jails are cool for isolating services and for configuration testing and such. Since it is not really virtualization the way vmware or xen or such are, you have much less overhead. Everything is running on one kernel — the processes inside the jail are just processes that are in a chroot environment and have limited networking. One big thing that is not available is the ability to alter the network stack in any way per jail.

By: Dan Langille

Dan Langille — Wed, 01 Aug 2007 14:22:20 +0000

“you can’t run different versions of the OS than what was originally installed”

AFAIK, you can run older versions of FreeBSD in the jail. For example, if you’re running 6.2 in the host, you could run 6.1 in the jail.