[macosx-unix] launchd [was: amanda backup]

[Bob Ippolito]

On Mar 16, 2006, at 10:54 AM, Jan Schaumann wrote:

> Jan Schaumann <jschauma at netmeister.org> wrote:
>
>> I'm quite sure that the plist itself, as is, is correct.  It does  
>> work
>> just fine when I manually 'launchctl load' it, after all.  It just
>> doesn't start automatically, *even though* it's actually loaded
>> automatically.  That is, after a fresh reboot, 'launchctl list' will
>> show me that org.amanda.amanda is a service that is running, only it
>> will not actually be running and nothing is listening on port 10080.
>
> I believe the problem is that the binary is located on a different
> Volume than the root Volume.  So at boot time, whenever launchd  
> actually
> starts all the services, the other Volume is not yet mounted.  When I
> log in lateron, it is mounted and re-starting the service works.
>
> launchd does not seem to allow you to specify a specific order -- I
> believe that that is actually somehow argued to be an advantage of
> launchd.

Instead of ordering, you specify dependencies via Uses/Requires/ 
Provides keys.  This lets launchd calculate an order that makes  
sense, and do independent things in parallel.  That's what makes it  
fast, because it doesn't have to do everything in serial in some  
specific order.

> In NetBSD, I can specify which partitions need to be mounted before  
> the
> system tries to start anything else, but I take it that under OS X
> that's not possible.  Probably one more of those ``Oh, why would  
> anybody
> want to do _that_?  Let's make it impossible.'' Apple things.
>
> Prove me wrong.  Please. :-)

Don't know this one.

-bob