Using WebLogic Server Clusters

 

Contents

 

Introduction to WebLogic Server Clustering

What Is a WebLogic Server Cluster?

What Services Are Clustered?

HTTP Session States

EJBs and RMI objects

JDBC Connections

JMS

Non-clustered Services and APIs

New Cluster Features in WebLogic Server Version 6.0

Integrated Support for Load Balancing Hardware

Stateful session EJB Clustering

Clustered JMS

HTTP Session State Replication Changes

Administration Changes in WebLogic Server Version 6.0

Multicast Message Changes

Homogeneous Deployment

Administration Server Configuration

Cluster Features and Infrastructure

Overview

Server Communication in a Cluster

One-to-Many Communication Using IP Multicast

Implications for Cluster Planning and Configuration

Peer-to-Peer Communication Using IP Sockets

Pure-Java Versus Native Socket Reader Implementations

Configuring Native Sockets

Configuring Reader Threads for Java Socket Implementation

Client Communication via Sockets

Cluster-Wide JNDI Naming Service

Creating the Cluster-Wide JNDI Tree

Handling JNDI Naming Conflicts

Homogeneous Deployment

Updating the JNDI Tree

Client Interaction with the Cluster-wide JNDI Tree

Load Balancing of Clustered Services

Load Balancing for HTTP Session States

Load Balancing for Clustered Objects

Round-Robin (Default)

Weight-Based

Random

Using Parameter-based Routing for Clustered Objects

Failover Support for Clustered Services

How WebLogic Server Detects Failures

Failure Detection Using IP Sockets

The WebLogic Server "Heartbeat"

Failover for Clustered Servlets and JSPs

Failover for Clustered Objects

Idempotent Objects

Other Failover Exceptions

Understanding HTTP Session State Replication

Overview

Requirements for HTTP Session State Replication

Proxy Requirements

Load Balancer Requirements

Session Requirements

Session Data Must Be Serializable

Use setAttribute() to Change Session State

Consider Serialization Overhead for Session Objects

Applications Using Frames Must Coordinate Session Access

Configuring In-Memory HTTP Replication in a Cluster

Using Replication Groups

Accessing Clustered Servlets and JSPs Using a Proxy

Using URL Re-writing to Track Session Replicas

Proxy Failover Procedure

Accessing Clustered Servlets and JSPs with Load Balancing Hardware

Failover with Load Balancing Hardware

Understanding Object Clustering

Overview

Replica-aware Stubs

Clustered EJBs

EJB Home Stubs

Stateless EJBs

Stateful EJBs

Entity EJBs

Clustered RMI Objects

Stateful Session Bean Replication

Replicating EJB State Changes

Failover for Stateful Session EJBs

Optimization for Collocated Objects

Transactional Collocation

Planning WebLogic Server Clusters

Overview

Capacity Planning

WebLogic Servers on Multi-CPU machines

Definition of Terms

Web Application "Tiers"

De-Militarized Zone (DMZ)

Load Balancer

Proxy Plug-In

Recommended Basic Cluster

Planning By Dividing Application Tiers

Recommended Multi-tier Architecture

Physical Hardware and Software Layers

Web/Presentation Layer

Object Layer

Benefits of Multi-tier Architecture

Load Balancing for Clustered Object Calls

Configuration Notes for Multi-tier Architecture

Limitations of Multi-tier Architecture

Firewall Restrictions

Recommended Proxy Architectures

Two-tier Proxy Architecture

Physical Hardware and Software Layers

Multi-tier Proxy Architecture

Proxy Architecture Trade-offs

Proxy Plug-in Versus Load Balancer

Administration Server for Cluster Architectures

Security Options for Cluster Architectures

Basic Firewall for Proxy Architectures

DMZ with Basic Firewall Configurations

Combining Firewall with Load Balancer

Expanding the Firewall for Internal Clients

Additional Security for Shared Databases

DMZ with Two Firewall Configuration

Firewall Considerations for Clusters

Administering WebLogic Clusters

Overview

Plan Your Cluster Architecture

Obtain a Cluster License

Obtain Network Addresses

WebLogic Server DNS names

Administration Server IP address

Cluster Multicast Address

Cluster DNS Name

Cluster Address List

Assigning Names to Server Instances

Install WebLogic Server

Define Machine Names

Create WebLogic Server Instances

Create a New Cluster

Configure Replication Groups

Configure Load Balancing Hardware (Optional)

Using Active Cookie Persistence

Using Passive Cookie Persistence

Configure Proxy Plug-ins (Optional)

Deploy Web Applications and EJBs

Starting a WebLogic Server Cluster

A. Troubleshooting Common Problems

Applying Service Packs A-1

Collecting Diagnostic Information A-2

Providing Diagnostics to BEA Technical Support A-3

Addressing Common Problems A-3

Tuning Connection Timeouts A-4

Server Fails to Join a Cluster A-4

B. The WebLogic Cluster API

How to Use the API B-1