Thoughts on jail.config

[Jamie Gritton]

On 06/28/10 08:24, Alexander Leidinger wrote:
> Quoting Jamie Gritton <jamie at FreeBSD.org> (from Thu, 24 Jun 2010
> 10:30:42 -0600):
>> On 06/24/10 06:43, Alexander Leidinger wrote:
 >>
>> Jails that exist outside of the config file's knowledge are a tricky
>> point, and the problems are really only on a shutdown request. While I
>> haven't coded this part of things yet, I've considered that I'll need
>> two different kinds of blanket shutdowns: one for all the jails in the
>> config file, and another for all jails in the system. The latter would
>> be the most sensible to use during system shutdown, when it doesn't make
>> sense to leave any jails running. But orderly shutdown is part of the
>> config spec (e.g. running "/bin/sh /etc/rc.shutdown"), and it may be
>> best to assume that if the jails were created outside of the rc system,
>> they'll be removed in the same way.
>
> There are two additional sides:
> 1) For jails which are created by example via ezjail I agree that it is
> within the responsability of the ezjail to shut them down.
> 2) For jails which are created/started by hand from a custom config file
> for testing purposes, I think a "shutdown all remeaining jails even if
> there is not entry in the config file" would be good. The problem with
> this is, that you need to make assumptions how to do a shutdown, or
> record this info in the kernel on creation time (and use this only if no
> config with appropriate info is available).

If any jails are left on shutdown by the time rc.d/jail gets to them,
they would have to be summarily killed. I wouldn't want to make
assumptions about scripts and the like in the absence of the config
lines, since I assume there's a reason they weren't started withing the
jail.conf system.

When you remove a jail via jail_remove(2), it sends a SIGKILL to every
process inside it. I could at least first send them a SIGTERM and give
them a little while to clean up first. But I still wouldn't to run a
script that wasn't specified by the jail creator, which is at this point
necessarily unknown.

So yes, I'd have a "shutdown all jails" option for this.

- Jamie