Tutorial for Hierarchical Jails?

[Jamie Gritton]

Edwin Shao wrote:
> Hello,
> Does anyone have a walkthrough for how to get hierarchical jails to work?
> I've been playing around with it for a couple of days and it simply is not
> working. I would like to know if anyone has gotten it to work, and if so,
> how?
> 
> The error I tend to get within a jail (starting another child jail) is:
> hyper# ./jail start
> Configuring jails:.
> Starting jails: cannot start jail "neko":
> 
> I'm using very basic steps as outlined in <
> http://www.freebsd.org/doc/en/books/handbook/jails-intro.html> and I am
> easily getting the jails to work in the non-jailed highest level system.
> 
> What I have done to troubleshoot so far:
> * Installed from scratch 8.0-RC1 ISO, make buildworld from scratch 8.0-RC1
> /usr/src.
> * Created very liberal sysctls.
> * Tried different combinations of disabling/enabling mounted systems such as
> devfs, procfs, etc.
> * Tried modifying different module fs to enable the "jail" flag.
> 
> This is under a clean install of 8.0-RC1. I'd be happy to provide additional
> information for troubleshooting, but I'm not even sure what's going wrong.
> It'd probably be more helpful for you to just let me know what you did to
> get it wroking.

The main thing you need to do is to set the first-level jail's
children.max parameter.  It defaults to zero, which doesn't allow a jail
to create any child jails (the non-hierarchical default).  It sounds
like you have everything else you need.

- Jamie