32-bit jails on a 64-bit system?

John Baldwin jhb at freebsd.org
Thu Jan 21 13:12:56 UTC 2010

On Thursday 21 January 2010 1:51:36 am Charles Sprickman wrote:
> Howdy,
> I saw this little tidbit in the 8.0 Release Notes...
> ----
> The jail(8) subsystem has been updated. Changes include:
> Compatibility support which permits 32-bit jail binaries to be used on 
> 64-bit systems to manage jails has been added.
> ----
> I know prior to 8.0 with some fancy footwork you could do some interesting 
> things (for example, I have a jail running a bunch of 32-bit 4.11 stuff on 
> a 7.2 amd64 box), but it was not easy.

The comment is a bit misleading, it just means you can use an i386 
/usr/sbin/jail binary on an amd64 system (presumably the same is true for 
other jail-related programs like jls).  It's probably not useful for the vast 
majority of folks.  Perhaps with nested jails it could be useful as a 32-bit 
jail on a 64-bit host can create child jails w/o needing to copy the 64-bit 
jail binary from the host into the jail.

There are still several binaries such as ps that need to be 64-bit, even in a 
32-bit jail.

John Baldwin

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