[Openais] Re: confchg_fn, cluster membership, etc.

Mark Haverkamp markh at osdl.org
Thu Sep 16 07:32:21 PDT 2004


On Wed, 2004-09-15 at 16:05, Steven Dake wrote:
> On Wed, 2004-09-15 at 15:53, Mark Haverkamp wrote:
> > On Wed, 2004-09-15 at 15:41, Steven Dake wrote:
> > > Mark,
> > > 
> > > I have had a look at the clm_get_by_nodeid and evt.c and have come to
> > > the conclusion that it is not possible to use this function in a
> > > configuration change function.
> > > 
> > > This is because some of the information cannot be gathered until after
> > > the configuration change has occured.  The nodejoin message is never
> > > sent until after a configuration change and the nodejoin message
> > > contains the node information (such as the timestamp of the boot, name,
> > > etc).  I'd rather not add all of that information into the gmi form
> > > token because we use too much space already for the membership algorithm
> > > and it would reduce scalability in the future.
> > > 
> > > One workaround to this problem is to develop a evt configuration change
> > > handler that doesn't use clm_get_by_nodeid.
> > > 
> > > For the join case, make evt_add_node send an executive message "add a
> > > node" (with the ip address) and make the executive message handler match
> > > the current body (with message decoding operations) of the evt_add_node
> > > function.
> > 
> > I was kind of working in that direction.  Although, if you look at my
> > EVT_CONF_CHANGE case in the patch for bug 43, I had to check for the
> > cluster node pointer being NULL because I don't always get a cluster
> > node, even there.
> > 
> 
> Yes you will need the EVS plug in order for this scheme to work
> correctly 100% of the time.

What is an evs plug-in?  Is that different than the evs service?

Mark.

-- 
Mark Haverkamp <markh at osdl.org>




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