hi lachezar,
i've got clustering working for our app but haven't used the rmi.xml
clustering settings. the app seems to failover ok to another machine in the
cluster if i switch a machine off, etc,.
we use only stateless session beans and so i wondered if only entity bean
information was exchanged over the port specified in rmi.xml
what's all this stuff for in rmi.xml
<cluster host="230.0.0.1" id="123" password="123abc" port="9127"
username="cluster-user" />
Tag that is defined if the application is to be clustered. Used to set up a
local multicast cluster. A username and password used for the servers to
intercommunicate also needs to be specified.
host - The multicast host/ip to transmit and receive cluster data on. The
default is 230.0.0.1.
id - The id (number) of this cluster node to identify itself with in the
cluster. The default is based on local machine IP.
password - The password configured for cluster access. Needs to match that
of the other nodes in the cluster.
port - The port to transmit and receive cluster data on. The default is
9127.
username - The username configured for cluster access. Needs to match that
of the other nodes in the cluster.
thanks,
greg.
----- Original Message -----
From: Lachezar Dobrev
To: Orion-Interest
Sent: Friday, June 15, 2001 6:18 PM
Subject: RMI Clustering done. Now want more.
Hello.
OK. I was able to (at last) run the RMI clustering. It now works. But...
I have a question...
Now I can put up a cluster, and when a bean does not exist on the server
it is searched on the cluster and used. However if it is deployed on more
than one machine... It is not found on all of them, but rather on only one.
For simplicity let's assume we have OrionA, OrionB, OrionC and OrionD.
a) on all machines we have EnterpriseBean1 deployed. It accesses
EnterpriseBean2
b) machine OrionA does not have EnterpriseBean2 deployed.
c) machines OrionB, OrionC and OrionD have EnterpriseBean2 deployed.
d) all machines have a RMI cluster set-up and working.
(BTW) Because I needed quite some time to understand why the
cluster was not working I am eager to help anyone, that needs
help on the subject.
If machine OrionA runs EnterpriseBean1 it will have to look-up
EnterpriseBean2, which is used by EnterpriseBean1.
There is no problem to find that bean (it exists on the cluster).
However... Once EnterpriseBean2 is used on OrionC it keeps using that one.
Why? Also. If we deploy EnterpriseBean2 on OrionA it is always found there
and not on ANY other cluster machine.
1. How does Orion know on which machine to use the bean? The last one,
that wakes up?
2. Is there a way to implement (at least) a round-robin technique to
access the clustered bean on more than one server? I mean... When I look-up
EnterpriseBean2... I would like to have a different server answering every
time. Round-robin is sufficient, even though a loadbalancing technique would
be better appropriate.
Ok. Waiting forward to hearing from you all...
P.S. Another question... CAN I TURN WEB-SERVICES OFF??? I tried removing
the default-web-app tag in the server.xml, but it starts complaining about
no default web-app :((( I want to have some Orion servers to act as EJB only
servers.
Lachezar
