On 13/11/2007, at 4:42 PM, Jeff Genender wrote:
Gianny Damour wrote:
You can successfully "distribute" when all the configured cluster
members are running. If one of them is down, then the installation
fails. This seems to be a typical scenario - at least based on the
clustered deployments I have been working with.
Hmmm...I have found this to be different...
I have found that if 1 node in the cluster is bad, it is removed from
the general cluster array (i.e. look at heartbeats and the
joining/leaving of a general cluster).
This is a valid use case. The 1 server could have a problem with
it...such as network, hardware, etc. Not clustering due to a bad
server
would defeat the purpose of providing for fail over.
I hope we are not talking about the same thing. I am talking about a
"deployment time" constraint and not a "runtime" constraint mandating
that all the servers are reachable when an application is *deployed*.
FWIW, such a constraint was also defined by WebLogic 7.0; from
WebLogic 8.x+, this constraint was subsequently relaxed in order to
allow the deployment to a sub-set of the cluster members - however,
users can still enforce it if they want and partial deployments is
not recommended. As previously said, it is trivial to implement a
GBean to distribute a backed configuration to a server, which was not
reachable upon deployment.
Thanks,
Gianny
Hence this is the
simplest implementation possible for this initial stab of clustered
deployment. Furthermore, as I explained in my email, there is a
carbon
copy of the already backed configuration within the master-repository
and it is trivial to: either improve the GBean in charge of the
remote
control of configurations; or to add new GBeans in order to
automatically upload this carbon copy to cluster members which
were not
running upon installation.
Also, you still need to honor my request for heads-up :). If you are
working on clustering, then could you please provide some headlines?
I am working on the EJB clustering and hope that we can both
communicate
on the list when we are committing in this area.
Jeff
