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Re: [Linux-cluster] rgmanager "depend" tag on RHEL4



On Monday 30 July 2007 16:15:25 Lon Hohberger wrote:
> On Fri, Jul 27, 2007 at 08:34:40PM +0200, Mark Hlawatschek wrote:
> > On Friday 27 July 2007 15:45:19 Lon Hohberger wrote:
> > > I think there's already a feature request open about it, by you?
> >
> > Yes, there are two feature requests open that address service
> > dependencies 247980 - RFE: (strong and weak) service dependencies
> > 247772 - RFE: One service following another
> >
> > > Implementation-wise, in RHEL5, there's an event queue for service state
> > > changes, and a function which broadcasts starts/stops
> > > (broadcast_event()).  The difference is that in RHEL5, you can
> > > multicast to all rgmanagers w/ one call - whereas on RHEL4, you have to
> > > open a connection to each and send the message individually.
> > >
> > > So, basically, it involves porting the event queue code and
> > > implementing broadcast_event().
> >
> > OK, how much effort - in your opinion - would it be to port/implement
> > these features ?
>
> 'follow' is harder to implement cleanly than strong vs. weak deps;
> mostly because it's a two-step process.  On RHEL5, it's easier due to
> the event mechanism (you can trigger off 'service started' statechange
> and move the conflicting service to another node).
>
> The easiest path would be to port the event mechanism to RHEL4.
> So, it's more likely to appear in RHEL5 first (less work).
>
> The current train of thought is something like this:
>
>   * A follows B
>
>   * When A transitions to started, move B to another
>     node if they are on the same node.
>
> > Is there a task scheduled to do these things ?
>
> I can find out.
>
> I assume you're willing to assist in testing, is that right?

I certainly will do a lot of testing :-)

Thanks,

Mark


-- 
Gruss / Regards,

Dipl.-Ing. Mark Hlawatschek
http://www.atix.de/
http://www.open-sharedroot.org/

**
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