DNS Names or IP Addresses? Consider the purpose of the cluster when When Internal and External DNS Names Vary If the internal and external DNS Localhost Considerations If you identify a server instances listen address as
10.1.5 Identify Names and Addresses
During the cluster configuration process, you supply addressing information—IP addresses or DNS names, and port numbers—for the server instances in the cluster. For information on intra-cluster communication, and how it enables load balancing and failover, see Section 3.1, WebLogic Server Communication In a Cluster. When you set up your cluster, you must provide location information for: ■ Administration Server ■ Managed Servers ■ Multicast location Read the sections that follow for an explanation of the information you must provide, and factors that influence the method you use to identify resources.10.1.5.1 Avoiding Listen Address Problems
As you configure a cluster, you can specify address information using either IP addresses or DNS names. 10.1.5.1.1 DNS Names or IP Addresses? Consider the purpose of the cluster when deciding whether to use DNS names or IP addresses. For production environments, the use of DNS names is generally recommended. The use of IP addresses can result in translation errors if: ■ Clients will connect to the cluster through a firewall, or ■ You have a firewall between the presentation and object tiers, for example, you have a servlet cluster and EJB cluster with a firewall in between, as described in the recommended multi-tier cluster. You can avoid translation errors by binding the address of an individual server instance to a DNS name. Make sure that a server instances DNS name is identical on each side of firewalls in your environment, and do not use a DNS name that is also the name of an NT system on your network. For more information about using DNS names instead of IP addresses, see Section 11.7.3, Firewall Considerations.10.1.5.1.2 When Internal and External DNS Names Vary If the internal and external DNS
names of a WebLogic Server instance are not identical, use the ExternalDNSName attribute for the server instance to define the servers external DNS name. Outside the firewall the ExternalDNSName should translate to external IP address of the server. If clients are accessing WebLogic Server over the default channel and T3, do not set the ExternalDNSName attribute, even if the internal and external DNS names of a WebLogic Server instance are not identical.10.1.5.1.3 Localhost Considerations If you identify a server instances listen address as
localhost, non-local processes will not be able to connect to the server instance. Only processes on the machine that hosts the server instance will be able to connect to the server instance. If the server instance must be accessible as localhost for instance, if you have administrative scripts that connect to localhost, and must also be accessible by remote processes, leave the listen address blank. The server instance will determine the address of the machine and listen on it. 10-4 Using Clusters for Oracle WebLogic Server10.1.5.2 Assigning Names to WebLogic Server Resources
Parts
» Oracle Fusion Middleware Online Documentation Library
» Document Scope and Audience Guide to this Document
» What Are the Benefits of Clustering? What Are the Key Capabilities of a Cluster?
» Servlets and JSPs EJBs and RMI Objects
» Getting Connections with Clustered JDBC Failover and Load Balancing for JDBC Connections
» Pure-Java Versus Native Socket Reader Implementations
» Client Communication via Sockets
» How WebLogic Server Creates the Cluster-Wide JNDI Tree
» How WebLogic Server Updates the JNDI Tree Client Interaction with the Cluster-Wide JNDI Tree
» Load Balancer Configuration Requirements Load Balancers and the WebLogic Session Cookie
» Related Programming Considerations How Session Connection and Failover Works with a Load Balancer
» Round-Robin Load Balancing Weight-Based Load Balancing
» Transactional Collocation Optimization for Collocated Objects
» Methods of Configuring Clusters Load Balancing for JDBC Connections
» Using Replication Groups HTTP Session State Replication
» Connection with Load Balancing Hardware Failover with Load Balancing Hardware
» Configuration Requirements for Cross-Cluster Replication
» Configuring Session State Replication Across Clusters
» Clustering Objects with Replica-Aware Stubs
» Failover and JDBC Connections Understanding Server and Service Migration
» Migration Terminology Oracle Fusion Middleware Online Documentation Library
» Features That Use Leasing Leasing Versions
» Determining Which Type of Leasing To Use High-availability Database Leasing
» Non-database Consensus Leasing Leasing
» Preparing for Automatic Whole Server Migration
» Configuring Automatic Whole Server Migration
» Startup Process in a Cluster with Migratable Servers
» Automatic Whole Server Migration Process
» Manual Whole Server Migration Process Administration Server Role in Whole Server Migration
» Migratable Server Behavior in a Cluster Node Manager Role in Whole Server Migration
» Cluster Master Role in Whole Server Migration
» JMS-related Services JTA Transaction Recovery Service
» Custom Store Availability for JMS Services Default File Store Availability for JTA
» Best Practices for Targeting JMS when Configuring Automatic Service Migration
» Architecture Web Application Tiers
» Combined Tier Architecture De-Militarized Zone DMZ Load Balancer Proxy Plug-In
» No Collocation Optimization Firewall Restrictions
» Multi-Tier Proxy Architecture Proxy Architecture Benefits Proxy Architecture Limitations
» Proxy Plug-In Versus Load Balancer
» DMZ with Two Firewall Configuration
» Dynamic Cluster Address If you do not explicitly define a cluster address
» Configuration Roadmap Install WebLogic Server
» Starting a WebLogic Server Cluster
» Configure Node Manager Configure Load Balancing Method for EJBs and RMIs
» Sample web.xml This section contains a sample deployment descriptor file
» Accessing Applications Via the Proxy Server Ensure that applications clients will
» Configure Replication Groups Configure Migratable Targets for Pinned Services
» Migrating When the Currently Active Host is Unavailable Use this migration
» Configure Multicast Time-To-Live TTL Configure Multicast Buffer Size
» Cluster-Related Configuration Options Follow Usage and Configuration Guidelines
» Manual Migration of the JTA Transaction Recovery Service State Management in a Cluster
» Naming Considerations Administration Server Considerations
» Firewall Considerations Avoiding Problems
» Check the Server Version Numbers Check the Multicast Address Check the CLASSPATH Value
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