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Re: Paralell startup



On Wed, 20 Oct 2004 16:39:07 -0400, Roberto Peon <grmoc yahoo com> wrote:
> How would falling back to serial boot help?
> 
> Not launching the services whose dependancies are not satisfied seems like a
> good idea to me. It is better than the current, try it anyway, and see it
> fail (sometimes spectacularly).

Uhm... i think you are mixing several different technical problems together.
Parallel booting addresses the specifc problem of how to order
'attempted' start up
of service scripts.  There is no reason to say that a later script
must not be 'attempted' if an eariler script in the ordering has a
problem.
You are using I think 'dependancy' in an all encomposing way to
include hard dependancies as well as conditional dependancies. Just
because a 'dependancy' fails to start doesn't mean a later service
doesn't launch. Services scripts can have conditional logic...
foo initscript
if network is running do this
if network is not running do that
bar initscript
if sshd is running do this
if sshd is not running do that

Are completely valid conditional checks that later scripts can use to
taste the state of the system and decide how to proceed. In these
cases network and sshd are still dependancies in the sense that they
need to be 'attempted' to be run for the conditional logic to have any
validity. The startup scripts for these services still need to be
'attempted' before my foo are bar services, but whether or not network
is running or sshd is running is not a failure state that causes foo
or bar to not be launced.

Service scripts that depend on something else running should be robust
enough to have conditional logic and do their own internal checking
for system state before attempting to doing something spectacularly
stupid. Lets not drag failure status into the debate about ordering.
Each initscript should internalize its own checks and do its own
conditional logic to check for system state. What parallel bootup
should be addressing is SOLELY how to order script start up. It should
not refuse to attempt to start up a script. If a script has been
requested to be on at boot...it should be run at some point in the
ordering...and its internal checks should be used to catch system
state problems.

-jef
-jef


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