Allowing meta-namespace in jail.conf

[James Gritton]

On 10/18/2013 2:42 PM, Dirk Engling wrote:
> Dear jail enthusiasts,
>
> in order to move forward with my jail management project ezjail, and
> make it support the new jail.conf way of managing jail configs, I need a
> way to add properties to jails that are currently not in the list of
> allowed parameters. I was thinking of something like
>
> web-jail {
>    name = 'www.test.com';
>    meta.ezjail.imagetype = 'zfs';
>    meta.ezjail.zfsdataset = 'tank/ezjail/www.test.com-data';
> }
>
> Alternatively, I could keep a shadow tree of config options and generate
> jail configs on the fly, but that would mean not using the power of the
> new jail config format. This can also lead to conflicting settings (e.g.
> from wildcard jails or global options) and unexpected parts of the
> system to look for configs.
>
> Another issue is the complexity of the jail.conf format which makes it
> hard to automatically manipulate entries. I've started working on a
> parser/generator in shell, but wondered if there are any plans to add a
> way to remove jail blocks (adding is easier) and add/modify/delete
> parameters in jail blocks. Some standardized way to get the result from
> jail(8)'s parser would of course be a nice start.
>
> Any thoughts on that?

I'd been thinking of a similar thing, but at a different level.  A
"jail environment" where these arbitrary parameters are visible inside
the kernel (and thus also via jls(8)).  I was considering a single
"env" parameter formatted like an environ(7) string, but I like your
presentation as separate parameters (though I would probably call them
"env.*" instead of "meta.*").

Regarding the jail.conf format, it would make sense to move its
parsing into libjail.  Then if we want we could add features like the
extra manipulation you mention.

- Jamie