This chapter describes the advantages of using Coherence*Web for managing session state in clustered environments. It lists the containers that can use Coherence*Web and provides an installation and deployment roadmap. More detailed information on installation, deployment, and features are provided in following chapters.
This chapter contains the following sections:
Coherence*Web is an HTTP session management module dedicated to managing session state in clustered environments. Built on top of Oracle Coherence (Coherence), Coherence*Web:
brings Coherence data grid's data scalability, availability, reliability, and performance to in-memory session management and storage.
can configure fine-grained session and session attribute scoping by way of pluggable policies (see "Session and Session Attribute Scoping").
can be deployed to many mainstream application servers such as Oracle GlassFish Server, Oracle WebLogic Server, IBM WebSphere, Tomcat, and so on (see "Supported Web Containers").
allows storage of session data outside of the Java EE application server, freeing application server heap space and enabling server restarts without session data loss (see "Deployment Topologies").
enables session sharing and management across different Web applications, domains and heterogeneous application servers (see "Session and Session Attribute Scoping").
can be used in advanced session models (that is, Monolithic, Traditional, and Split Session) that define how the session state is serialized or deserialized in the cluster (see "Session Models").
For WebLogic Server 12c (12.1.3), Coherence*Web is integrated with the product. No installation is necessary. For more information, see Chapter 2, "Using Coherence*Web with WebLogic Server."
For third-party application servers, Coherence*Web provides a generic installer, the WebInstaller, that transparently instruments your Web applications. Chapter 4, "Using Coherence*Web on Other Application Servers," describes how to use the WebInstaller to install Coherence*Web on these servers.
Table 1-1 summarizes the Web containers supported by the Coherence*Web session management module. It also provides links to the information required to install Coherence*Web. Notice that all of the Web containers (except Oracle WebLogic Server 10.3.4) share the same general installation instructions. A few, such as Caucho Resin, and WebLogic 10.n, require extra, container-specific steps that you must complete before starting the general installation instructions.
Note:
The value in the Server Type Alias column is used only by the Coherence*Web WebInstaller installation. The value is passed to the WebInstaller through the-server command-line option.Table 1-1 Web Containers which can use Coherence*Web
There are deployment decisions you should make before you configure and deploy Coherence*Web. Coherence*Web is supported on many different application servers. Regardless of which application server you are using, you might have to change some Coherence*Web configuration options to meet your particular requirements, such as packaging considerations, session model, session locking mode, and deployment topology.
Cluster node isolation refers to the scope of the Coherence nodes that are created within each application server JVM. Several different isolation modes are supported.
For example: you might be deploying multiple applications to the container that require the use of the same cluster (or one Coherence node); you might have multiple Web applications packaged in a single EAR file that use a single cluster; or you might have Web applications that must keep their session data separate and must be deployed to their own individual Coherence cluster. These choices and the deployment descriptors and elements that must be configured are described in "Cluster Node Isolation".
Locking mode refers to the behavior of HTTP sessions when they are accessed concurrently by multiple Web container threads. Coherence*Web offers several different session locking options. For example, you can allow multiple nodes in a cluster to access an HTTP session simultaneously, or allow only one thread at a time to access an HTTP session. You can also allow multiple threads to access the same Web application instance while prohibiting concurrent access by threads in different Web application instances. These choices, and the deployment descriptors and elements that must be configured, are described in "Session Locking Modes".
Session and session attribute scoping refers to the fine-grained control over how both session data and session attributes are scoped (or shared) across application boundaries. Coherence*Web supports sharing sessions across Web applications and restricts which session attributes are shared across the application boundaries. These choices, and the deployment descriptors and elements that must be configured, are described in "Session and Session Attribute Scoping".
Coherence*Web provides a session reaper, which invalidates sessions that have expired. Chapter 7, "Cleaning Up Expired HTTP Sessions," describes the session reaper.
The installation procedure that you follow depends on your application server. "Supported Web Containers" provides a list of the application servers and the corresponding instructions for installing Coherence*Web.
If you are using a recent release of WebLogic Server (such as 12c (12.1.3)) Coherence and Coherence*Web are installed with the WebLogic Server product. No separate Coherence*Web installation is necessary. See Chapter 2, "Using Coherence*Web with WebLogic Server."
For other application servers, use the generic Java EE WebInstaller described in Chapter 4, "Using Coherence*Web on Other Application Servers."