C Oracle Application Server Clusters Managed Without Oracle Notification Server (ONS)

This appendix describes how to set up and run OracleAS Clusters without using Oracle Notification Server (ONS). This is a manual way of creating and managing a group of Oracle Application Server instances as a cluster. The automated way is covered in Chapter 3, "Active-ActiveTopologies".

This appendix contains the following sections:

• Section C.1, "About OracleAS Clusters Managed Without ONS"

• Section C.2, "Configuration Tasks"

C.1 About OracleAS Clusters Managed Without ONS

You cluster a group of Oracle Application Server instances for routing purposes. If an instance in a cluster fails, requests are routed to another instance in the cluster. If you use OracleAS Clusters managed without ONS, you as the administrator have to configure the clusters manually. You do this by editing configuration files.

The OracleAS Clusters managed without ONS feature is intended for users of Oracle Application Server Java Edition. In the Oracle Application Server Java Edition, the OracleAS Clusters managed with ONS feature is not available.

The following list describes the features available in the OracleAS Clusters managed with ONS that are not available in OracleAS Clusters managed without ONS:

• Dynamic discovery - In OracleAS Clusters managed with ONS, you use a multicast address to define the cluster. Instances that use the same multicast address are automatically joined to a cluster.

  In OracleAS Clusters managed without ONS, you have to edit the configuration file on each instance to add/remove instances to/from a cluster.

• Application mount points automatically configured - In OracleAS Clusters managed with ONS, application mount points are automatically managed.

  In OracleAS Clusters managed without ONS, you have to edit the configuration file on each instance to add/remove application mount points.

• Dynamic OPMN-managed peer-to-peer replication - In OracleAS Clusters managed with ONS, you can add a tag in the orion-application.xml file to specify that the list of peers to replicate to is provided dynamically by OPMN.

  In OracleAS Clusters managed without ONS, you can use static peer-to-peer replication.

C.2 Configuration Tasks

To set up OracleAS Clusters managed without ONS, you perform these configurations:

• Configure static peer-to-peer replication

  You configure static peer-to-peer replication by listing the peers in the orion-application.xml file.

  For details, see section "Configuring Static Peer-to-Peer Replication" in chapter 9, "Application Clustering in OC4J", in the Oracle Containers for J2EE Configuration and Administration Guide.

• Create mount points

  You create mount points by editing the ORACLE_HOME/Apache/Apache/conf/mod_oc4j.conf file. You use the Oc4jMount directive to define the mount points. (In OracleAS Clusters managed with ONS, mount points are managed for you and do not appear in the mod_oc4j.conf file.)

  For details on creating mount points, see section 7.32, "mod_oc4j", in the Oracle HTTP Server Administrator's Guide.

• Configure routing to specific instances on a per-URL basis

  You can configure mod_oc4j to forward requests to specific instances by editing the ORACLE_HOME/Apache/Apache/conf/mod_oc4j.conf file. You use the destination parameter of the Oc4jMount directive to specify where the request for an application should be directed.

  For details on specifying the destination, see section 7.32, "mod_oc4j", in the Oracle HTTP Server Administrator's Guide.

OracleAS Clusters managed without ONS do not use the OPMN membership for routing or replication because both routing and session replication are hardcoded.