Sun Java System Application Server Enterprise Edition 8.1 2005Q2 High Availability Administration Guide

- Previous: Chapter 5 Using Application Server Clusters
- Next: Working with Named Configurations

# About Named Configurations

- Named Configurations

- The default-config Configuration

- Configurations Created when Creating Instances or Clusters

- Unique Port Numbers and Configurations

## Named Configurations

A named configuration is a set of server configuration information, including settings for things such as HTTP listeners, ORB/IIOP listeners, JMS brokers, the EJB container, security, logging, and monitoring. Applications and resources are not defined in named configurations.

Configurations are created in the administration domain. Multiple server instances or clusters in the domain can reference the same configuration, or they can have separate configurations.

For clusters, all server instances in the cluster inherit the cluster’s configuration so that a homogenous environment is assured in a cluster’s instances.

Because a named configuration contains so many required configuration settings, create a new configuration by copying an existing named configuration. The newly-created configuration is identical to the configuration you copied until you change its configuration settings.

There are three ways in which clusters or instances use configurations:

- Stand-alone: A stand-alone server instance or cluster doesn’t share its configuration with another server instance or cluster; that is, no other server instance or cluster references the named configuration. You create a stand-alone instance or cluster by copying and renaming an existing configuration.

- Shared: A shared server instance or cluster shares a configuration with another server instance or cluster; that is, multiple instances or clusters reference the same named configuration. You create a shared server instance or cluster by referencing (not copying) an existing configuration.

- Clustered: A clustered server instance inherits the cluster’s configuration.

  See Also:

- The default-config Configuration

- Configurations Created when Creating Instances or Clusters

- Unique Port Numbers and Configurations

- To Create a Named Configuration

- Editing a Named Configuration’s Properties

## The default-config Configuration

The `default-config` configuration is a special configuration that acts as a template for creating stand-alone server instance or stand-alone cluster configurations. No unclustered server instances or clusters are allowed to refer to the `default-config` configuration; it can only be copied to create new configurations. Edit the default configuration to ensure that new configurations copied from it have the correct initial settings.

For more information, see:

- Configurations Created when Creating Instances or Clusters

- Named Configurations

- To Create a Named Configuration

- Editing a Named Configuration’s Properties

- To Edit Port Numbers for Instances Referencing a Configuration

## Configurations Created when Creating Instances or Clusters

When creating a new server instance or a new cluster, either:

- Reference an existing configuration. No new configuration is added.

- Make a copy of an existing configuration. A new configuration is added when the server instance or cluster is added.

By default, new clusters or instances are created with configurations copied from the `default-config` configuration. To copy from a different configuration, specify it when creating a new instance or cluster.

For a server instance, the new configuration is named instance_name`-config` . For a cluster, the new configuration is named cluster-name `-config`.

For more information, see:

- The default-config Configuration

- Named Configurations

- To Create a Named Configuration

- Editing a Named Configuration’s Properties

## Unique Port Numbers and Configurations

If multiple instances on the same host machine reference the same configuration, each instance must listen on a unique port number. For example, if two server instances reference a named configuration with an HTTP listener on port 80, a port conflict prevents one of the server instances from starting. Change the properties that define the port numbers on which individual server instances listen so that unique ports are used.

The following principles apply to port numbers:

- Port numbers for individual server instances are initially inherited from the configuration.

- If the port is already in use when you create a server instance, override the inherited default value at the instance level to prevent port conflicts.

- Assume an instance is sharing a configuration. The configuration has port number n. If you create a new instance on the machine using the same configuration, the new instance is assigned port number n+1, if it is available. If it is not available, the next available port after n+1 is chosen.

- If you change the port number of the configuration, a server instance inheriting that port number automatically inherits the changed port number.

- If you change an instance’s port number and you subsequently change the configuration’s port number, the instance’s port number remains unchanged.

  For more information, see:

- To Edit Port Numbers for Instances Referencing a Configuration

- Editing a Named Configuration’s Properties

- Named Configurations

- Previous: Chapter 5 Using Application Server Clusters
- Next: Working with Named Configurations

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