[Openais] Adding a service

Steven Dake sdake at mvista.com
Mon Jul 19 14:00:33 PDT 2004


On Mon, 2004-07-19 at 12:45, Mark Haverkamp wrote:
> On Mon, 2004-07-19 at 11:37, Sabharwal, Atul wrote:
> > >I have been looking at adding the event service to openais.  I 
> > >have some
> > >code that I have been working with that now runs using the TIPC network
> > >driver for the sending and receiving events.  I had intended 
> > >to start by
> > >having the event service code use the openais membership API 
> > >library and
> > >still use TIPC for communication, then move to using the openais
> > >communication code. 
> > 
> > You could start with membership and communication at the same time
> > Using the GMI library. The gmi_join call does the membership
> > And gmi_mcast does the transmission.  I have attached my syslog
> > Code which uses the GMI library for trasnmit and receive. It should
> > Get you started.
> 
> Thanks,  I'll take a look at it.
> 
> I haven't looked closely at the gmi code.  Is the membership using
> gmi_join used to set up communication between processes?  It's not the
> cluster membership provided by the AIS API is it?
> 

The gmi code does both membership and ordered delivery (and soon
authentication and encryption) of messages with virtual synchrony
semantics.  Their integration is required for various reasons relating
to virtual synchrony.

The idea is that AIS services use the service_handler structure and
services provided by the openais executive to communicate with other
processors and the APIs users.  Processor to processor communication
occurs through the gmi layer and delivery function.

The gmi delivery function basically calls the correct message handler
for the message identifier.  This delivery function then generally does
the work of the ais service, responding back to the api if "itself" was
the processor that sourced the api request.

The GMI code also calls a configuration change handler whenever a
configuration change occurs (ie: the membership changes).  This is the
optimal mechanism to get membership information as a ais service (vs
using the SA Forum membership API).  This is required vs implementing
against the SA Forum membership api because the membership api doesn't
guarantee VS, hence, correct operation in a partition or merge may not
be guaranteed.

Regards
-steve

Regards-steve
> Mark.
> 
> 
> > 
> > Regards,
> > 
> > Atul




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