Sun Cluster Data Service for Sun Java System Application Server Guide for Solaris OS

Sun Cluster HA for Sun Java System Application Server Overview

This section explains how the Sun Cluster HA for Sun Java System Application Server enables Sun Java System Application Server for high availability. Consult the Sun Cluster Data Service Release Notes for Solaris OS for any new Sun Cluster HA for Sun Java System Application Server installation and configuration information.

See Chapter 1, Planning for Sun Cluster Data Services, in Sun Cluster Data Services Planning and Administration Guide for Solaris OS and the Sun Cluster Overview for Solaris OS for general information about data services, resource groups, resources, and other related topics.

The Sun Java System Application Server provides a robust Java 2 Enterprise Edition (J2EE™) platform for the development, deployment, and management of enterprise applications. Key features include transaction management, performance, scalability, security, and integration.

The Sun Java System Application Server supports services from web publishing to enterprise-scale transaction processing, while enabling developers to build applications based on JavaServer PagesTM (JSPTM), Java servlets, and Enterprise JavaBeansTM (EJBTM) technology. The Sun Java System Application Server Enterprise Edition provides advanced clustering and failover technologies. These features enable the user to run scalable and highly available J2EE applications.

Rich clients can directly connect to the Sun Java System Application Server. Web client connections to the Sun Java System Application Server can be directed through a front-end web server. The Sun Java System Application Server provides a pass-through plugin installation for use with the Sun Java System Web Server.

Highly Available Components

The Sun Java System Application Server supported versions as of 8.1 consists of several components.

Implementation of the Sun Cluster HA for Sun Java System Application Server does not assume the existence of programs on which your architecture depends. Programs on which your architecture depends such as databases and web servers should be configured to be highly available, but can run on a different cluster.

Highly Available DAS and NA

The Sun Cluster HA for Sun Java System Application Server provides high availability that complements the high availability provided by the Sun Java System Application Server Enterprise Edition. The Sun Cluster HA for Sun Java System Application Server makes the DAS highly available by running it as a failover Sun Cluster data service. The Node Agents are made highly available by running them as a failover Sun Cluster data service. As a functionality provided by the Sun Java System Application Server Enterprise Edition, the Node Agents in turn make the Sun Java System Application Server instances highly available.

Highly Available Message Queue and HADB

The Sun Java System Application Server EE installs the Sun Java System Message Queue and the Sun Java System Application Server EE (HADB).

See Sun Cluster Data Service for Sun Java System Message Queue Guide for Solaris OS for information about configuring the Sun Java System Message Queue for high availability.

See Sun Cluster Data Service for Sun Java System Application Server EE (HADB) Guide for Solaris OS for information about configuring the Sun Java System Application Server EE (HADB) for high availability.

Supported Configurations

The Sun Cluster HA for Sun Java System Application Server makes the DAS component highly available by configuring it as a failover data service. The DAS must be configured to listen on a failover IP address. When Sun Cluster HA for Sun Java System Application Server detects a failed DAS, the data service restarts the DAS locally or fails it over to another node, depending on the values of the retry count and retry interval.

The Node Agent (NA) component is also configured as a failover data service. A Node Agent may be configured to manage a number of Application Server instances, and the Sun Cluster HA for Sun Java System Application Server data service indirectly manages all of these instances. All the Application Server instances are associated with the Node Agents and the Node Agents are configured to listen on a failover IP address.

If the Application server instances are down, the Node Agents will restart them. Any lost transactions are recovered while the instances are restarting. In the case of a crash of the Sun Cluster node on which the Node Agents and the Application Server instances are running, the Sun Cluster HA for Sun Java System Application Server fails over the Node Agent and the Application Server instances to another Sun Cluster node.


Note –

Only one Node Agent resource is created for all the Node Agents configured for one failover IP address. The data service automatically detects the Node Agents that are configured on the failover IP address that is created in the failover resource group.

The following example is a configuration that comprises four Node Agents.

In this example, you create one resource for Node Agents NA1 and NA2 and all their server instances, and another resource for Node Agents NA3 and NA4 and all their server instances.

A detailed example of creating resources for four Node Agents is provided in Example of Creating the Failover Node Agent Component in the Sun Cluster HA for Sun Java System Application Server.

In the following sections, only two Node Agents are illustrated.


Before Node Failure

The following figure illustrates the failover DAS and failover Node Agent configuration before any node failure occurs.

Figure 1–1 DAS and Node Agents Configured as Failover—Before Node Failure

The preceding context describes the graphic.

The figure illustrates the following setup.

Bringing these resource groups online starts the Node Agents, which in turn start the Application Server instances that they manage.

After Node Failure

The following figure illustrates the failover DAS and failover Node Agent configuration after a node failure.

Figure 1–2 DAS and Node Agents Configured as Failover—After Node Failure

The preceding context describes the graphic.

After a failure on Node1, resource groups RG1 and RG2 fail over to Node2. Resource group RG1 contains the DAS and its failover address IP1. Resource group RG2 contains Node Agent NA1, instances I1 and I2, and their failover address IP2.


Note –

The Node Agent probe relies upon the DAS for getting the status of the Node Agent. If DAS fails, there is no way to determine the status of the Node Agent. You need to ensure that the DAS is running at all times to know the status of the Node Agent.