7 Configuring Coherence Clusters

This chapter describes how to configure the Oracle Communications Services Gatekeeper Oracle Coherence storage provider.

Understanding Coherence

Coherence is used for clustering in Services Gatekeeper. The storage service uses Coherence for cluster-wide storage.

In a basic domain configuration, a default Coherence configuration is created when you create the domain. If you support a clustered environment, you must create a Coherence configuration.

Coherence supports two different types of addressing:

  • Multicast, where all messages are broadcast to all servers in the network.

  • Unicast, where the servers in the network tier are aware of the IP-addresses, or host-names, of all servers in the tier and only send messages to this well-known set of addresses.

Configure the Coherence cluster-related attributes such as multicast address and port, unicast address, and port overrides using the administration console. Oracle WebLogic Server stores the attributes in the WebLogic configuration repository and makes them available to the Coherence cluster service.

Configuring Coherence in GeoRedundancy Scenarios

When you configure Coherence clusters to support georedundancy scenarios, do the following:

  • Use unicast type of addressing.

  • Add Well Known Addresses (WKA) for the NT servers.

  • Configure Coherence servers for each NT server, if necessary.

Such a configuration setup helps avoid issues when servers share hardware. For example, it prevents Coherence logic from using any multicast addresses during cluster discovery thereby ensuring that the servers joining the correct cluster. See "Best Practices for Domain-Specific GeoRedundant Services".

Configuring Coherence

To configure Coherence, complete the following steps:

Configure Coherence Cluster Properties 

  1. Log in to the administration console and click Lock& Edit.

  2. In the Domain Structure pane, expand the Environment section.

  3. Click Coherence Clusters.

  4. Click New.

    The Create Coherence Cluster Configuration screen is displayed.

  5. Enter Coherence-OCSG in the Name field. This is a fixed value and must be entered exactly as stated.

  6. Ensure that Use a custom Cluster Configuration File is not selected.

  7. Click Next.

    The Coherence Cluster Addressing page is displayed.

  8. To configure Coherence clusters, the recommended option is to always use unicast addressing, whether in a georedundant scenario or in a standalone configuration. Complete the steps described under Configure Unicast Addresses.

    • In a standalone configuration, you can configure Coherence to use multicast addressing. Complete the steps described under Configure Multicast Addresses.

Configure Unicast Addresses 

  1. In the Unicast Listen Port field, enter the port for the cluster unicast listener. The default unicast listen port is 8088.

  2. Click Next.

    The Coherence Cluster Members page is displayed.

  3. Proceed to the section, Configure Coherence Cluster Members.

Configure Multicast Addresses 

  1. In the Multicast Listen Address field, enter the IP address for the cluster multicast listener.

  2. In the Multicast Listen Port field, enter the port for the cluster multicast listener.

  3. Click Next.

    The Coherence Cluster Members page is displayed.

  4. Proceed to the section, Configure Coherence Cluster Members.

Configure Coherence Cluster Members 

  1. Select all network tier servers as Coherence Cluster targets by selecting the check-box in front of Network_Tier_Cluster_Name, where Network_Tier_Cluster_Name is the name of your network tier cluster.

  2. Click the All servers in the cluster radio-button in the Network_Tier_Cluster_Name group.

  3. Click Finish.

    The Summary of Coherence Clusters page is displayed.

Configure the well known addresses (WKA) for this Coherence Cluster 

  1. Click Coherence-OCSG.

    The Settings for Coherence-OCSG page is displayed.

  2. Click the Well Known Addresses tab.

    The Well Known Addresses page is displayed.

  3. For each network tier server:

    1. Click New.

      The Coherence Cluster configuration Properties page is displayed.

    2. In the Name field, enter the name of the Coherence cluster configuration.

    3. In the Listen Address field, enter the IP address to listen to.

    4. In the Listen Port field, enter the port to listen to.

    5. Click OK.

Check the Coherence Settings for Unicast Addressing 

  1. Go to each NT server and check its Coherence setting:

    1. In Domain Structure, click on Environment, then Servers and WLNG_NT1 in that order.

    2. On the Settings for WLNG_NT1 page, click on the Configuration tab.

    3. From the selections for Configuration, click on the Coherence tab.

    4. Verify or set the the entry in the Unicast Listen address field, for this server.

    5. Verify that the Unicast Listen Port field is set to 0.

  2. Click Release Configuration.