[JBoss-user] Clustering is available for use

Bill Burke Sat, 20 Oct 2001 14:51:59 -0700

Hi all,

Sacha Labourey and I would like to announce the availability of new JBoss clustering features in RabbitHole-3.0 (the mainline). There is still a lot of testing to be done so this is really BETA code. If you have any questions, pop either one of us an email on the jboss-dev list. I'll be in Las Vegas next week so hopefully Sacha can answer all questions for now. The below HOWTO will be merged into documentation eventually when one of us has time.

Regards,

Bill

Features

You must have JDK 1.3.x Will not work with JDK earlier than this. Sorry....
Built on top of JavaGroups. http://www.javagroups.com
Automatic group discovery. Cluster nodes can automatically find eachother(BUT THEY DON"T SHARE CONFIGURATIONS!)
A general framework wrapped around JavaGroups that provides group communications thru RPCs, a state transfer protocol, and membership change notification
Cluster-wide JNDI (a.k.a HA-JNDI)
Failover for HA-JNDI, Stateless Session Beans, Entity Beans, and also any RMI object you want to replicate
method calls are collocated if possible even if the proxy is serialized to another node.
SLSB, HA-JNDI, and Home calls are load-balanced Round Robin. Entity Bean calls are NOT load-balanced.

Quick Start

Get latest and build from CVS mainline (RH 3.0) (Don't ask me how to do this!)
Copy .../jboss-all/cluster/etc/cluster-service.xml to JBoss's deploy/ directory
Edit any SLSB or EntityBean's "jboss.xml" to put in <clustered> flag (see .../jboss-all/cluster/etc/jboss.xml for example

i.e.

<jboss>
    <secure>false</secure>

    <enterprise-beans>
        <session>
            <ejb-name>nextgen.StatelessSession</ejb-name>
            <jndi-name>nextgen.StatelessSession</jndi-name>
            <clustered>True</clustered>
        </session>
        <entity>
            <ejb-name>nextgen.EnterpriseEntity</ejb-name>
            <jndi-name>nextgen.EnterpriseEntity</jndi-name>
            <clustered>True</clustered>
        </entity>
   </enterprise-beans>

</jboss>

To use HA-JNDI you must have a list of cluster nodes in the provider URL list separated by commas, HA-JNDI runs off of port 1100 by default:

java.naming.provider.url=server1:1100,server2:1100,server3:1100

HA-JNDI is NOT a required service. You can connect to any cluster node's local JNDI.

Problems you may encounter

Only JDK 1.3.x is supported. It will not work with an earlier JDK.
Do NOT use <commit-option> 'A' with Entity Beans!!!
If you want to synchronize Entity Beans across the cluster use <select-for-update> Unfortunately this feature may only work with Oracle :-(. We will be expanding this feature later on.
Clustered beans do NOT support Transaction Propagation unless the method call is collocated.
We think we've fixed this problem, but if you bring 2 clustered nodes up at the same time and have problems, start them completely one at a time.
MERGEing doesn't work well yet. What is Merging? Let's say a part of the cluster becomes separated from the group because of a bad network switch or something. These orphaned nodes don't die, but are just cut off from the network. When these orphaned nodes are hooked up to the network again, JBoss Clustering(through JavaGroups) will merge the orphaned nodes into the group. This does not work well all the time.

Advanced Setup

How clustering is configured will expand over time, but here's what can be configured right now.

Advanced Cluster Configuration

One JBoss instance can belong to multiple different clusters.(Beans can only belong to one cluster though!) You can do this by plopping another mbean into jboss and give a name for the specific cluster.

Cluster configuration variables(these can be defined as mbean properties in cluster-service.xml for example):

PartitionName: Name the cluster partition. The default is "DefaultPartition"

PartitionProperties: Defines JavaGroups properties. see http://www.javagroups.com for more information

i.e.

<depends>JBOSS-SYSTEM:service=Naming</depends>

<attribute name="PartitionName">MySpecialPartition</attribute>

<attribute name="PartitionProperties">UDP:PING:FD:VERIFY_SUSPECT:MERGE:NAKACK(trace=true):UNICAST:FRAG:FLUSH:GMS:STATE_TRANSFER:QUEUE</attribute>

</mbean>

</server>

Advanced HA-JNDI Confugration

You can only define the JNDI listen port at this time in the mbean. The default is 1100

i.e.

<depends>JBOSS-SYSTEM:service=Naming</depends>

</server>

Advanced Bean Configuration

Advanced Bean configuration is minimal at this time. You can only define the Cluster Partition that the bean is attached to.

<jboss>
<secure>false</secure>

    <enterprise-beans>
      <session>
        <ejb-name>nextgen.StatelessSession</ejb-name>
        <jndi-name>nextgen.StatelessSession</jndi-name>
        <clustered>True</clustered>

<cluster-config>

<partition-name>MySpecialPartition</partition-name>

        </cluster-config>
      </session>
    </enterprise-beans>

[JBoss-user] Clustering is available for use

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