jail.conf & cpuset.id

Jamie Gritton jamie at FreeBSD.org
Thu Mar 21 13:32:46 UTC 2013

On 03/17/13 05:59, Nicolas de Bari Embriz Garcia Rojas wrote:
> Hi, all, I am start using the jail.conf for running my jails, in rc.local I have this line jail -c this to start my jails at boot time (any better ideas)
> Now checking the man pages for the jail I found a option that cough my attention, 'cpuset.id'  any idea of how to use it ?
> I would like to found a way to prevent a root user within a jail to run a 'fork-bum' and freeze the host server.

Take a look at cpuset(1). You use that utility (in the host environment)
to change the CPUs available to a jail. Don't worry about the cpuset.id
parameter itself - you don't need it. Just use cpuset's "-j" flag to
specify the jail itself (by jid only). When you're starting jails in rc,
add the appropriate cpuset commands an exec_poststart option. Such as:

jail_backtest_poststart0="cpuset -c -l1,3-7 -j`cat 

- Jamie

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