Troubleshooting boot problems
Patrick Goetz
pgoetz at mail.utexas.edu
Wed Apr 21 16:19:29 UTC 2010
>
> Subject: Re: Troubleshooting boot problems
> From: Florian Diesch <diesch at spamfence.net>
> Date: Wed, 21 Apr 2010 12:18:40 +0200
>
> Any event can be emitted by any program using upstart's DBus API.
>
> IMHO it's not that important to know where a event gets emitted
> (that's an implementation detail) but what it actually
> means.
>
I'm not sure I agree with this. I understand that an event driven
system isn't linear (see previous discussion thread) but some services
do have linear dependencies; i.e. there are some services which can only
be started after others (yes, I realize this is an event dependency --
it's still a linear relationship).
The example I provided should be adequate: most iptables scripts start
by flushing the tables. If I have a custom table I need/want to have,
it's important to me to know if ufw is running before or after my
script, since I don't want my iptables rules to be flushed when the
system is fully booted. The question: does ufw run before or after the
rc2.d scripts? is a question about a linear ordering, and an
administrator should be able to determine this what looking at source
code or jumping through a bunch of hoops. Perhaps a program like
pstree, but for events, would be useful?
Speculation about how to suspend a service is all well and good
(commenting out the start line seems logical) but there should be an
*official* way to do this to avoid problems down the road.
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