Configuring Coherence

Oracle Coherence enables organizations to predictably scale mission-critical applications by providing fast and reliable access to frequently used data. By automatically and dynamically partitioning data in memory across multiple servers, Coherence enables continuous data availability and transactional integrity, even in the event of a server failure.

WebLogic Server domains include a Coherence container that simplifies the management and deployment of Coherence clusters and Coherence-based applications.

Coherence Clusters and Managed Coherence Servers

Coherence is integrated within WebLogic Server as a container subsystem, known as a Coherence cluster. The use of a container aligns the lifecycle of a Coherence member with the lifecycle of a Managed Server: starting or stopping a server JVM starts and stops a Coherence cluster member.

A WebLogic Server domain can contain a single Coherence cluster that can be associated with multiple WebLogic Server clusters. Within a Coherence cluster are Coherence cluster members.

Managed Coherence servers are Managed Servers that are configured to be Coherence cluster members. Managed Coherence servers provide in-memory distributed caching for applications to increase application scalability, availability, and performance.

Managed servers can be explicitly associated with a Coherence cluster or they can be associated with a WebLogic Server cluster that is associated with a Coherence cluster.

Managed Coherence servers that are part of a WebLogic Server cluster inherit their Coherence settings from the WebLogic Server cluster. WebLogic Server clusters are typically used to set up Coherence deployment tiers that organize managed Coherence servers based on their role in the Coherence cluster.

For more information, see Configuring and Managing Coherence Clusters in Administering Clusters for Oracle WebLogic Server.

Configure Coherence: Main Steps

For optimal performance or scalability, Coherence is typically set up using WebLogic Server clusters to represent deployment tiers.

1. Verify whether your domain’s topology can support separate WebLogic Server clusters to represent Coherence deployment tiers. For guidance, see Cluster Architectures in Administering Clusters for Oracle WebLogic Server.

   Alternatively, for development purposes, you can set up a single standalone Managed Server instance to act as both a cache server and a cache client. See Configure and Deploy Coherence on a Single-Server Cluster.

   Single-server topologies are not recommended for production use.

2. Configure a Coherence cluster as described in Create a Coherence Cluster.

3. Configure a data tier as described in Create a Coherence Data Tier.

   A Coherence data tier is a WebLogic Server cluster that is associated with a Coherence cluster and hosts any number of storage-enabled managed Coherence servers. For more information, see Configuring and Managing a Coherence Data Tier in Administering Clusters for Oracle WebLogic Server.

4. Configure an application tier as described in Create a Coherence Application Tier.

   A Coherence application tier is a WebLogic Server cluster that is associated with a Coherence cluster and hosts any number of storage-disabled managed Coherence servers. For more information, see Configuring and Managing a Coherence Application Tier in Administering Clusters for Oracle WebLogic Server.

5. Configure a proxy tier as described in Create a Coherence Proxy Tier.

   A Coherence proxy tier is a WebLogic Server cluster that is associated with a Coherence cluster and hosts any number of managed Coherence proxy servers. Managed Coherence proxy servers allow Coherence*Extend clients to use Coherence caches without being cluster members. For more information, see Configuring and Managing a Coherence Proxy Tier in Administering Clusters for Oracle WebLogic Server.

6. Create and package a Coherence Grid Archive (GAR) module for any application modules (Web application, EJB, and so on) that use Coherence. For more information, see Creating Coherence Applications for WebLogic Server in Developing Oracle Coherence Applications for Oracle WebLogic Server.

7. Deploy your Coherence GAR module to your WebLogic Server domain as described in Install an Application.

   Standalone GARs are deployed in the same way as other Java EE modules. For more information, see Deploying Coherence Applications in WebLogic Server in Developing Oracle Coherence Applications for Oracle WebLogic Server.

Create a Coherence Cluster

Coherence clusters enable applications to share data management and caching services among server instances and clusters hosting the applications that need access to them.

Configure cluster properties and then target Coherence clusters to WebLogic Server instances or clusters in the domain.

1. In the Edit Tree, go to Environment, then Coherence Clusters.

2. Click New.

3. Enter a name for the Coherence cluster and click Create.

4. Select a Clustering Mode and then adjust the Coherence general properties according to the clustering mode you selected.

5. If you want to specify operational settings that are not available through the provided MBeans, you can upload a cluster configuration file with your supplemental settings. Click Import Configuration, then, in the Custom Cluster Configuration File Name dialog box, enter the location of the cluster configuration file, relative to the domain configuration directory.

   Avoid configuring the same operational settings in both an external cluster configuration file and through the MBeans.

6. Click Save.

Next, you should consider updating the following configuration options:

• Target Coherence Clusters

• Configure Coherence Federation

• Configure Coherence Persistence

• Set Up the Coherence Security Framework

Configure Coherence Clusters

A Coherence cluster provides several cluster settings that can be configured for a specific domain.

You should update the default values of the Coherence cluster as needed for your environment.

Configure Coherence Federation

Use Coherence federation to federate cache data asynchronously across multiple geographically dispersed clusters. Federating cached data across clusters provides redundancy, off-site backup, and multiple points of access for application users in different geographical locations.

For more information, see Federating Caches Across Clusters in Administering Oracle Coherence.

1. In the Edit Tree, go to Environment, then Coherence Clusters.

2. Click the Coherence cluster that you want to edit, then select the Coherence Federation tab.

3. Select a Federation Topology from the drop-down list.

   When a topology is selected, a topology configuration is automatically created and named Default-Topology. The Default-Topology topology configuration is created and used if no other federation topology is specified in the cache configuration file.

   When using federation, complementary topologies must be configured on both the local and remote clusters. For example, if a local cluster is set to use active-passive, then the remote cluster must be set to use passive-active.

4. In the Remote Coherence Cluster Name field, enter the name of the remote cluster to which this cluster is being federated.

5. In the Remote Participant Hosts field, enter one or more hosts (separated by commas) that are running managed Coherence servers on the remote cluster.

6. If required, change the cluster port of the remote cluster in the Remote Coherence Cluster Listen Port. The default cluster port is typically not changed.

7. Click Save.

Configure Coherence Persistence

Use Coherence persistence to save and recover Coherence distributed caches. Cached data is persisted so that it can be quickly recovered after a catastrophic failure or after a cluster restart due to planned maintenance.

For more information on configuring persistence in Coherence, see Persisting Caches in Administering Oracle Coherence.

1. In the Edit Tree, go to Environment, then Coherence Clusters.

2. Click the Coherence cluster that you want to edit, then select the Coherence Persistence tab.

3. Choose a Persistence Mode from the drop-down list.

   • On-Demand: In this mode, a cache service is manually persisted and recovered upon request using the persistence coordinator. The persistence coordinator is exposed as an MBean interface that provides operations for creating, archiving, and recovering snapshots of a cache service.
   • Active: In this mode, cache contents are automatically persisted on all mutations and are automatically recovered on cluster/service startup. The persistence coordinator can still be used in active persistence mode to perform on-demand snapshots.
   • Active-Async: In this mode, the storage servers can persist data asynchronously. Thus, a mutating request is successful after the primary stores the data and (if there is a synchronous backup) after the backup receives the update.
   • Active Backup: In this mode, persistence behaves similarly to the active persistence mode but it also stores backup partitions asynchronously on a disk.

4. You can override the default locations where various persistence files are stored. Enter new file locations in the appropriate fields:

   • Active Directory
   • Snapshot Directory
   • Trash Directory
   • Backup Directory
   • Events Directory

5. Click Save.

Configure Coherence Logging

You can configure logging properties for a Coherence cluster.

1. In the Edit Tree, go to Environment, then Coherence Clusters.

2. Click the Coherence cluster that you want to edit, then select the Logging tab.

3. Make sure the Enabled option is turned on.

4. In the Logger Name field, enter the logger name for the Coherence logs.

5. In the Message Format field, enter the Coherence logs message format.

6. In the Severity Level field, enter the logging severity level for Coherence logs. The maximum level you can set is 9.

7. In the Character Limit field, enter the character limit for Coherence logs.

8. Click Save.

Set Up the Coherence Security Framework

You can enable and configure the Coherence security framework. If you do not enable security, then any non-WebLogic Server JVM can access the Coherence cluster without going through WebLogic Server authorization.

For more information, see Securing Oracle Coherence in Oracle WebLogic Server in Securing Oracle Coherence.

1. In the Edit Tree, go to Environment, then Coherence Clusters.

2. Click the Coherence cluster that you want to edit, then select the Security tab.

3. Turn on the Security Framework Enabled option and then configure the security parameters to meet the requirements of your environment.

   If the Secured Production option is not set, Coherence will inherit its domain mode from WebLogic Server.

4. Click Save.

5. Enable an Identity Asserter for a Coherence cluster to assert a client’s identity token. For local extend clients, an identity asserter is already enabled for asserting a token of type weblogic.security.acl.internal.AuthenticatedSubject. For remote (outside of WebLogic Server) extend clients, a custom identity asserter implementation class must be packaged in a GAR. However, an identity asserter is not required if the remote extend client passes null as the token. If the proxy service receives a non-null token and there is no identity asserter implementation class configured, a SecurityException is thrown and the connection attempt is rejected.

   1. Under the current Coherence cluster node in the navigation tree, select Coherence Identity Asserter.

   2. In the Class Name field, enter the fully qualified name of the asserter class. For example, to use the default identity asserter, enter com.tangosol.net.security.DefaultIdentityAsserter.

   3. Click Save.

   4. If there are any arguments, open the Identity Asserter Constructor Arguments node and click New to add class constructor arguments.

   5. Click Save.

If you want to define WebLogic Server roles and policies for authorizing access to Coherence services and caches, see Secure a Coherence Service Configuration or Secure Coherence Caches, respectively.

Target Coherence Clusters

Target Coherence clusters to WebLogic Server instances or clusters that host applications that need access to Coherence data caches and services.

1. In the Edit Tree, go to Environment, then Coherence Clusters.

2. Click the Coherence cluster that you want to edit, then select the Members tab.

3. Select the servers or clusters where you want to deploy the Coherence cluster configuration and move them under Chosen. Move any unwanted servers or clusters under Available.

4. Click Save.

Create a Cluster Cache Configuration

A Coherence cache configuration file defines the caches and services that are used by an application. Typically, a cache configuration file is included in a GAR module.

A GAR is deployed to all managed Coherence servers in the data tier and can also be deployed as part of an EAR to the application tier. The GAR ensures that the cache configuration is available on every Coherence cluster member.

However, there are cases that require a different cache configuration file to be used on specific managed Coherence servers. For example, a proxy tier requires access to all artifacts in the GAR but needs a different cache configuration file that defines the proxy services to start.

You can use WebLogic Remote Console to define a cluster cache configuration. A cache configuration file can be associated with WebLogic clusters or Managed Coherence Servers at runtime. In this case, the cache configuration overrides the cache configuration file that is included in a GAR. You can also omit the cache configuration file from a GAR file and assign it at runtime.

To override a cache configuration file at runtime, the cache configuration file must be bound to a JNDI name. The JNDI name is defined using the override-property attribute of the element. The element is located in the coherence-application.xml file that is packaged in a GAR file. For more information on the coherence-application.xml file, see coherence-application.xml Deployment Descriptor Elements in Developing Oracle Coherence Applications for Oracle WebLogic Server. For more information on importing a cache configuration file, see Overriding a Cache Configuration File in Administering Clusters for Oracle WebLogic Server.

1. If you haven’t already done so, create a Coherence cluster. See Create a Coherence Cluster.

2. In the Edit Tree, go to Environment, then Coherence Clusters, then myCoherenceCluster, then Coherence Cache Configs.

3. Click New.

4. In the Name field, enter a name for the Coherence cache configuration.

5. In the JNDI Name field, enter the JNDI name to which the cache configuration file is bound.

   This JNDI name is prefixed with cache-config/ and must match the value in the override-property of your cache-configuration-ref entry in coherence-application.xml.

   For example, JNDI name of ExamplesGAR must match the override-property of cache-config/ExamplesGAR.

6. In the Cache Configuration File field, enter the full path to the cache configuration file. Alternatively, you may specify a URL.

7. Click Create.

8. On the Targets tab, select the servers or clusters where you want to target the cluster cache configuration and move them under Chosen. Move unwanted servers or clusters under Available.

9. Click Save.

Secure Coherence Caches

Use WebLogic Server authorization to restrict access to specific Coherence caches.

1. If you haven’t already done so, create a Coherence cluster. See Create a Coherence Cluster.

2. In the Edit Tree, go to Environment, then Coherence Clusters, then myCoherenceCluster, then Coherence Caches.

3. Click New.

4. In the Name field, enter a name for the Coherence cache. The name of the cache must match exactly the name of the cache used in an application.

5. Click Create and commit your changes.

6. Apply a security role that is scoped to the Coherence cache. See Create a Scoped Role.

Secure a Coherence Service Configuration

You can use WebLogic Server authorization to restrict access to Coherence services. Specifying authorization on a cache service affects access to all the caches that are created by that service.

1. In the Edit Tree, go to Environment, then Coherence Clusters, then myCoherenceCluster, then Coherence Services.

2. Click New.

3. In the Name field, enter a name for the Coherence service. The name of the service must match exactly the name of the service used in an application.

   The exact name must include the scope name as a prefix to the service name. The scope name can be explicitly defined in the cache configuration file or, more commonly, taken from the deployment module name. For example, if you deploy a GAR named contacts.gar that defines a service named ContactsService, then the exact service name is contacts:ContactsService.

4. Click Create and commit your changes.

5. Apply a security role that is scoped to the Coherence service. See Create a Scoped Role.

Specify a Coherence Well Known Address

Configure a well known address for a Coherence cluster. Other members can use this address to enroll in the cluster.

1. In the Edit Tree, go to Environment, then Coherence Clusters, then myCoherenceCluster, then Coherence Cluster Well Known Addresses.

2. Click New.

3. In the Name field, enter a name for the Coherence well known address.

4. In the Listen Address field, enter the IP address of the Coherence cluster member.

5. Click Create.

Configure a Coherence Address Provider

An address provider specifies the TCP listener address (IP or DNS name, and port) for a proxy service.

1. In the Edit Tree, go to Environment, then Coherence Clusters, then myCoherenceCluster, then Coherence Address Providers.

2. Click New.

3. In the Name field, enter a name for the Coherence address provider.

4. Click Create.

   A node for the new address provider will appear under the Coherence Address Providers.

5. Expand the new node and go to Coherence Socket Addresses.

6. Click New.

7. Enter a name for the socket address.

8. In the Address field, specify the listen address for your socket address.

9. In the Port field, specify the listen port for your socket address.

10. Click Create.

Coherence Deployment Tiers

In production environments, Coherence is typically set up using WebLogic Server clusters to represent deployment tiers.

There are three types of Coherence deployment tiers:

• Data Tier which hosts one or more cache servers
• Application Tier which hosts one or more cache clients
• Proxy Tier which hosts one or more managed Coherence proxy servers and the Coherence extend client tier that hosts extend clients

The tiered topology approach provides optimal scalability and performance.

For more information on Coherence deployment tiers, see Creating Coherence Deployment Tiers in Administering Clusters for Oracle WebLogic Server.

Create a Coherence Data Tier

A Coherence data tier is a WebLogic Server cluster that is associated with a Coherence cluster and hosts any number of storage-enabled managed Coherence servers.

For more information on Coherence data tiers, see Configuring and Managing a Coherence Data Tier in Administering Clusters for Oracle WebLogic Server.

1. If you haven’t already done so, create a Coherence cluster as described in Create a Coherence Cluster.

2. Create a WebLogic Server cluster as described in Create a Cluster.

3. On the WebLogic Server cluster that you just created, go to the Advanced tab, then the Coherence subtab.

4. From the Coherence Cluster System Resource drop-down list, select the Coherence cluster.

5. Turn on the Local Storage Enabled option.

6. Click Save.

7. Create one or more managed Coherence servers as described in Create a Managed Coherence Server and assign them to this data tier.

You should also create a Coherence application tier and, optionally, a Coherence proxy tier. See Create a Coherence Application Tier or Create a Coherence Proxy Tier.

Create a Coherence Application Tier

A Coherence application tier is a WebLogic Server cluster that is associated with a Coherence cluster and hosts any number of storage-disabled managed Coherence servers.

For more information on Coherence application tiers, see Configuring and Managing a Coherence Application Tier in Administering Clusters for Oracle WebLogic Server.

1. If you haven’t already done so, create a Coherence cluster as described in Create a Coherence Cluster.

2. Create a WebLogic Server cluster as described in Create a Cluster.

3. On the WebLogic Server cluster that you just created, go to the Advanced tab, then the Coherence subtab.

4. From the Coherence Cluster System Resource drop-down list, select the Coherence cluster.

5. Turn off the Local Storage Enabled option. Servers in the application tier should never be used to store cache data.

6. Click Save.

7. Create one or more managed Coherence servers as described in Create a Managed Coherence Server and assign them to this application tier.

You should also create a Coherence data tier and, optionally, a Coherence proxy tier. See Create a Coherence Data Tier or Create a Coherence Proxy Tier.

Create a Coherence Proxy Tier

A Coherence proxy tier is a WebLogic Server cluster that is associated with a Coherence cluster and hosts any number of managed Coherence proxy servers. Managed Coherence proxy servers allow Coherence*Extend clients to use Coherence caches without being cluster members.

The number of managed Coherence proxy servers that are required in a proxy tier depends on the number of expected clients. At least two proxy servers must be created to allow for load balancing. However, additional servers may be required when supporting a large number of client connections and requests.

For details on Coherence*Extend and creating extend clients, see Introduction to Coherence*Extend in Developing Remote Clients for Oracle Coherence.

1. If you haven’t already done so, create a Coherence cluster as described in Create a Coherence Cluster.

2. Create a WebLogic Server cluster as described in Create a Cluster.

3. On the WebLogic Server cluster that you just created, go to the Advanced tab, then the Coherence subtab.

4. From the Coherence Cluster System Resource drop-down list, select the Coherence cluster.

5. Turn off the Local Storage Enabled option. Servers in the proxy tier should never be used to store cache data.

6. Click Save.

7. Create one or more managed Coherence servers as described in Create a Managed Coherence Server and assign them to this proxy tier.

You should also create a Coherence data tier and a Coherence application tier. See Create a Coherence Data Tier and Create a Coherence Application Tier.

Create a Managed Coherence Server

A Managed Coherence server is a Managed Server that is configured to be Coherence cluster member and provide in-memory distributed caching for applications.

1. Create a WebLogic Server Managed Server, as described in Create a Managed Server.

2. On the Managed Server that you just created, from the Cluster drop-down list, select a cluster that is acting as a Coherence deployment tier.

   For information on Coherence deployment tiers, see Coherence Deployment Tiers.

3. Click Save.

Configure and Deploy Coherence on a Single-Server Cluster

During development, a single-server cluster offers a quick way to start and stop a cluster. A single-server cluster is a cluster that is constrained to run on a single managed server instance and does not access the network. The server instance acts as a storage-enabled cluster member, a client, and (optionally) a proxy.

For more information on using a single-server Coherence cluster, see Using a Single-Server Cluster in Administering Clusters for Oracle WebLogic Server.

1. If you haven’t already done so, create a Coherence cluster as described in Create a Coherence Cluster.

   If you are using multicast communication, set Time To Live to 0. For more information about communication for Coherence clusters, see Configure Cluster Communication in Administering Clusters for Oracle WebLogic Server.

2. Create a WebLogic Server Managed Server, as described in Create a Managed Server.

   Do not create a managed Coherence server.

3. On the Managed Server that you just created, go to the Advanced tab and then its Coherence subtab.

4. From the Coherence Cluster System Resource drop-down list, select the Coherence cluster.

   This standalone Managed Server will now inherit settings directly from the Coherence cluster.

5. Turn on the Local Storage Enabled option to ensure the Managed Server will be a storage-enabled Coherence member (cache server).

6. Set the Unicast Listen Address to an address that is routed to loop back. On most computers, setting the address to 127.0.0.1 works.

   For more information about unicast settings for Coherence cluster members, see Configure Coherence Cluster Member Unicast Settings in Administering Clusters for Oracle WebLogic Server.

7. Click Save.

8. Create and package a Coherence Grid Archive (GAR) module for any application modules (Web application, EJB, etc.) that use Coherence. See Creating Coherence Applications for WebLogic Server in Developing Oracle Coherence Applications for Oracle WebLogic Server.

9. Deploy your Coherence GAR module to your WebLogic Server domain. Standalone GARs are deployed in the same way as other Jakarta EE modules. See Deploying Coherence Applications in WebLogic Server in Developing Oracle Coherence Applications for Oracle WebLogic Server.