Managing Network Resources

The network configuration for a WebLogic Server domain is specified by

• Servers

• Clusters

• Machines

These are the first three subnodes below the domain in the navigation tree. The following sections provide information for specifying the network configuration for the WebLogic Server.

Configuring a Server

A configured instance of WebLogic Server is the definition of a server. Each server runs in its own Java Virtual Machine (JVM), using its own configuration. The WebLogic Server domain must have one server that acts as the administration server. The Administration Console is hosted on the administration server. A typical production environment also has one or more managed servers, which are instances of WebLogic Servers used to host enterprise applications.

Creating, configuring, and monitoring servers is one of the most important and common tasks performed with the Administration Console. The server is the engine that executes your Web applications and services and, therefore, proper configuration is key to providing a high-performance, reliable platform. Adding and Removing Servers in an Existing Domain is one of the links on the Common System Administration Tasks help page. This page can be accessed directly from the Administration Console home page. A complete step-by-step guide is provided for all aspects of creating, configuring, and removing managed servers.

As shown in Figure 35.11, the Servers console page displays a table of key information about each server that has been configured in the current WebLogic Server domain. The page also contains links to Configure a New Server and Customize This View.

Clicking on the Configure a New Server link opens the console page to create a WebLogic Server instance. The configuration for a WebLogic Server is organized under seven tabs:

• General

• Cluster

• Keystores & SSL

• Deployment

• Tuning

• Health Monitoring

• Remote Start

The choices for configuring a new server very much depend on how the server will be used. For example, WebLogic provides a Java application called Node Manager that enables you to control the managed servers in a cluster. Certain configuration attributes of the server must be specified to make the managed server accessible to Node Manager. The parameters that are required for Node Manager are defined later in this section.

In addition, the servers in a cluster communicate with each other through the multicast of cluster events. If you want the new server to listen for cluster multicast events, you must configure the cluster before configuring the server. See Chapter 36, "Installing, Configuring, and Deploying WebLogic Server Clusters," for further information about clusters.

The General tab under Configuration contains the form to create a new WebLogic Server. After creating a new server, the other tabs on the console page for the server become enabled. The new server will run on a host computer, and optionally be a member of a cluster. The server configuration attributes Machine and Cluster provide this information. The choices for the Machine attribute are (none) or a list of configured machines. The server needs to be assigned to a machine if you want to use Node Manager to start the server; otherwise, the default value (none) can be used. If you're using Node Manager, you must configure the Machine attribute before configuring the server.

By default, a server is accessed through the IP address or hostname of the computer that is hosting the server. As always, if the request is from the same computer as the server, localhost can be used as the hostname. The configuration for the Listen Address enables you to restrict the valid listen addresses for the server. By specifying localhost explicitly as the Listen Address, only processes residing on the same machine as the server can to connect to the server. For this configuration, the client must explicitly specify localhost as the hostname to connect to the server. If you specify an IP address or DNS name, attempts to connect using localhost will fail.

After the new server has been created, its entry appears in the table of configured WebLogic Servers, as shown in Figure 35.11 earlier in this chapter. Clicking on the server name in the table opens the configuration for that server. The general configuration tab will now contain a link to show the advanced options for that server in addition to the general configuration options shown previously. The advanced options enable you to specify options for the Java compiler, RMI compiler, and EJB compiler when one of these compilers is used by this server. The additional advanced options include the startup mode for the server, which can be specified as either RUNNING or STANDBY. The significance of the Startup Mode setting is specified in the console help text.

The Cluster tab is enabled for each configured WebLogic Server. The configuration of the cluster enables you to define how this server will behave when it is part of a cluster. After creating the cluster, you must configure servers to be a member of the cluster.

The Keystores & SSL tab contains the console page for specifying the keystores and SSL configurations. A keystore is a mechanism designed to create and manage files that store private keys and trusted certificate authorities (CAs) for use with SSL. The console page allows you to view and change the various keystore configuration and Secure Sockets Layer (SSL) settings for this server. These settings help you to manage the security of message transmissions. Figure 35.12 shows the Keystore Configuration portion of the Keystores & SSL console page. Figure 35.13 shows the SSL Configuration portion of the same page. With the exception of the keystore passphrase, the format of this console page requires you to click on the Change link before it allows you to set any other values for the configuration.

The Deployment configuration page for a WebLogic Server enables you to define the default staging mode for this server. This allows you to control whether application files are uploaded to the administration server or copied to a managed server during deployment. The directory path for staging or uploading is also specified in this configuration.

The Tuning configuration page enables you to provide settings to tune the performance of this server. There are many e-docs to help you specify the tuning configuration that bests suits your system requirements.

The advanced options for Tuning are divided into Memory Options and Managed Server Independence. The Memory Options enable you to control this server's automatic detection and correction of low memory conditions. The Managed Server Independence settings enable you to control the availability of the managed server in the absence of the administration server.

The health monitoring capability for a server is used to improve the reliability and availability of the servers in a WebLogic Server domain. The configuration for health monitoring primarily enables you to give permission to the Node Manager to restart or shut down servers that fail their self-health monitoring criteria.

Finally, the Remote Start tab enables you to specify the settings that the Node Manager uses to start this server on a remote machine. The Node Manager is a standalone Java program provided by WebLogic Server that you can use to start, restart, monitor, and shut down managed servers.

Configuring Server Protocols

The Protocols tab on a server's console page enables you to define connection settings for various communication protocols. As shown in Figure 35.14, the five tabs for configuring protocols are

• General

• HTTP

• jCOM

• IIOP

• Channels

Notice that all general protocol settings are listed as Advanced Options. The general configuration for server protocols specifies default values that can be overridden by the network channel. The timeout settings enable you to specify criteria for error detection for connections and messages on the network channel. The maximum message size helps prevent denial-of-service attacks by specifying the maximum amount of memory that the server can allocate for the message. The protocol configuration also enables you to enable tunneling. If you use the T3, T3S, HTTP, HTTPS, IIOP, or IIOPS protocols, you must enable tunneling.

Web-based clients communicate with the WebLogic Server using HTTP (Hypertext Transfer Protocol). The HTTP settings control the communication between Web-based clients and WebLogic Server. The HTTP protocol settings for a WebLogic Server improve performance of the Web-based clients and help prevent denial-of-service attacks when set properly. The Default Server Name should be set to the hostname of your default HTTP Web server. The Post Timeout setting prevents the server from being overloaded with POST data that might have been caused as a denial-of-service attack. The Max Post Size enables you to limit the amount of HTTP Post data in a servlet request. The default Max Post Size is -1, which indicates an unlimited number of bytes. It is recommended to set the Enable Keepalives option to possibly improve performance of your Web applications. When keepalives are enabled, the Duration field specifies the number of seconds to maintain the HTTP Keepalive before timing out the request. Similarly, HTTPS Duration specifies the number of seconds for the secure HTTPS Keepalive timer.

The HTTP protocol also includes advanced options. The help text for many of these options includes a tip in parentheses of when that option might be necessary for your Web applications.

The jCOM protocol enables you to use COM (Component Object Model) objects from Java applications. COM is the underlying software architecture that performs client/server-based interprocess communication for Microsoft Windows applications. One of the most common implementations based on COM is ActiveX, which provides a Microsoft-language-neutral interface that allows Visual C++ and Visual Basic applications to invoke methods on a Dynamic Loaded Library (DLL) in an ActiveX server. All jCOM settings are contingent on jCOM being enabled. The Administration Console help for jCOM provides a direct link to the e-docs for "Programming WebLogic jCOM." The console help also includes a step-by-step guide for "Enabling and Configuring jCOM."

The IIOP protocol enables you to use CORBA (Common Object Request Broker Architecture) objects from Java applications. All IIOP settings are contingent on IIOP being enabled and are listed as Advanced Options. The Administration Console help for IIOP provides a direct link to the e-docs for "Programming WebLogic RMI over IIOP." The console help also includes a step-by-step guide for "Enabling and Configuring the IIOP Protocol."

As noted previously, you configure a network channel to be used in place of the listen address for a server. A network channel enables you to listen for requests on multiple ports, as well as separate network traffic by physical NIC cards. The Administration Console help for network channels provides direct links to the e-docs for "Understanding Network Channels" and "Configuring Network Channels." The Administration Console help also includes a Tasks link to the step-by-step guide for "Configuring a Custom Network Channel for a Non-Clustered Server."

Configuring Server Logging

The Logging tab on a server's console page enables you to define logging settings for various WebLogic Server resources and communication protocols. As shown in Figure 35.15, the five tabs for configuring logging are

• Server

• Domain

• HTTP

• JDBC

• JTA

The Server tab enables you to define the general logging settings for this server. The Domain tab enables you to specify whether this server logs to the WebLogic Server domain log file. To configure a domain log filter, refer to the "Configuring Domain Log Filters" section later in this chapter. The HTTP and JDBC tabs enable you to enable and disable logging for the particular protocol. HTTP logging is enabled by default, and JDBC logging is disabled by default. The JTA tab enables you to specify the path prefix for the JTA transaction log files.

Monitoring Servers

The Monitoring tab for a server enables you to monitor general information about the server. The five tabs provided on the Monitoring page are

• General

• Performance

• Security

• JMS

• JTA

The General tab enables you to monitor general information about the selected server. Figure 35.16 shows the general monitoring console page with the Advanced Options. This page contains three links to enable you to

• Monitor All Active Queues

• Monitor All Connections

• Monitor All Active Sockets

The Performance tab enables you to monitor performance information about the selected server. As shown in Figure 35.17, the Performance Monitoring page shows three graphs that are dynamically updated to show throughput, queue length, and memory usage for the selected server. This page also provides a button to enable you to force garbage collection on the server that is being monitored. There is also a link to modify graphing preferences. This is simply a direct link to the Console Preferences page shown in Figure 35.5 earlier in this chapter.

The Security tab enables you to monitor security information about the selected server, as well as unlock a user on that server. Figure 35.18 shows the console page for monitoring security information on a server.

The JMS tab enables you to monitor JMS information about the selected server. Figure 35.19 shows the JMS Monitoring console page. This page contains three links to enable you to

• Monitor All Active JMS Connections

• Monitor All Active JMS Servers

• Monitor All Pooled JMS Connections

The JTA tab enables you to monitor statistics about transactions coordinated by the selected server. Figure 35.20 shows the JTA Monitoring console page.

Controlling Servers

The Control tab for a server enables you to change the state of the current server. You can also view the current status of the server. The six tabs provided under the Control tab are

• Start/Stop

• Remote Start Output

• JMS Migration Config.

• JMS Migrate

• JTA Migration Config.

• JTA Migrate

The Start/Stop tab enables you to change the state of the selected server. Figure 35.21 shows the Start/Stop Control console page.

The Remote Start Output tab enables you to view the standard out and standard error output from the selected server and the output from the Node Manager. Figure 35.22 shows the Remote Start Output console page.

In addition, the Control tab for a server also includes four tabs to enable you to configure and perform a migration for a JMS server or JTA Transaction Recovery Service from a failed server to another server in the cluster. The server must be a member of a cluster in order to migrate the JMS or JTA service to another server in the same cluster. The capability to administer failover through migration is key to the high availability and reliability of the WebLogic Server cluster. The Administration Console help for both JMS Migration Config and JTA Migration Config provide direct links to the common related topics on e-docs:

• Migrating a Pinned Service to a Target Server Instance

• Migrating When the Currently Active Host Is Unavailable

By default, you can migrate the JMS server or JTA server to any other server in the cluster. The JMS Migration Config and JTA Migration Config enable you to specify a list of chosen target servers to limit the servers that can be the target for the migration.

The JMS Migrate tab and JTA Migrate tab enable you to specify the attributes for the respective migration. The Cluster attribute is the name of the cluster that the server is a member of. The Current Server attribute is the name of the server that currently owns the respective service. Finally, the Destination Server attribute is the server that the respective service will be migrated to. The Destination Server is selected from a list of chosen target servers.

Viewing Deployments on a WebLogic Server

The Deployments tab on the server console page enables you to view key information about the deployments that have been made on the selected server. The tabs under Deployments are organized in the same manner as the subnodes in the navigation tree.

• Applications

• EJB Modules

• Web Modules

• Connector

• Startup/Shutdown

The console page for these tabs displays key information about the deployment. See the section "Deploying Applications and Modules" later in this chapter for information on how to configure an application or module for deployment.

Viewing Services on a WebLogic Server

The Services tab on the server console page enables you to view key information about the J2EE and WebLogic objects that have been deployed as services on the selected server. The tabs under Services are organized as follows:

• JDBC

• JMS

• Web Services

• Bridge

• XML

• WTC

• Jolt

• Virtual Hosts

• Mail

• File T3

The console page for each tab displays key information about the service. See the section "Configuring WebLogic and J2EE Services" later in this chapter for information about how to configure a service for deployment.

Configuring Clusters

One server in a cluster must be designated as the administration server while the other servers are managed servers. Figure 35.23 shows the Clusters console page, which enables you to view the key fields for configured clusters as well as to create a new cluster.

Clicking on the name of a configured cluster or clicking the Configure a New Cluster link opens the console page for the cluster. The configuration for a cluster is organized on three tabs:

• General

• Multicast

• Servers

General Configuration for a Cluster

The general configuration console page is used to create the first instance of the cluster. After the cluster has been created, the remaining configuration tabs become enabled. The general configuration specifies the clusterwide configuration parameters, including the cluster address and default load algorithm. The cluster address identifies the managed servers in the cluster and is used by Entity and Stateless EJBs to construct the hostname portion of URLs. The cluster address may be specified as a comma-separated list of the hostnames or IP addresses. However, in a production environment, it is recommended to specify a DNS hostname that maps to the addresses of the managed servers in the cluster. The Administration Console help for clusters contains a Tasks link to a step-by-step guide for "Configuring a Cluster." The console help also provides direct links to the related e-docs topics "Cluster Address" and "Load Balancing Algorithms for RMI Objects and EJBs." Both of the e-docs related topics are in "Using WebLogic Server Clusters."

Multicast Configuration for a Cluster

IP multicast is a simple broadcast technology that is used by the servers in the cluster to communicate service availability and heartbeat messages to each other. The servers subscribe to a given IP address and port number to listen for these messages. A multicast address is an IP address in the range from 224.0.0.0 to 239.255.255.255. The configuration for the cluster multicast enables you to specify the multicast address and port number along with additional configuration attributes.

Servers Configuration for a Cluster

The Servers configuration enables you to add servers to the cluster from a list of configured servers. The servers that are added as cluster members listen for cluster multicast events. Figure 35.24 shows the Servers Configuration console page.

Configuring Machines

A machine identifies the physical system that hosts one or more WebLogic Server instances. The machine must also run Node Manager to enable you to control managed servers on that machine from a remote machine. Figure 35.25 shows the Machines console page, which enables you to view the key fields for configured machines as well as to create a new machine.

The console page for a machine is opened by clicking on the name of a configured machine or by clicking the Configure a New Machine or Configure a New Unix Machine link. The configuration for a machine is organized on three tabs:

• General

• Node Manager

• Servers

The general configuration for a machine that hosts a WebLogic Server is dependent on whether it is running a Unix-based operating system, such as Sun Solaris, or a non-Unix operating system, such as Microsoft Windows.

The Node Manager tab enables you to configure the listen address and listen port for Node Manager. As mentioned previously, Node Manager enables you to control managed servers from a remote machine, and is required if you want to use the Administration Console to control managed servers.

The Servers Configuration page for a machine enables you to select the servers that run on the machine from a list of configured servers. Figure 35.26 shows the console page for configuring servers for a machine.

The Administration Console help for Machines contains Task links for Configuring a Machine, Cloning a Machine, Deleting a Machine, and Assign a WebLogic Server Instance to a Machine. The console help also provides direct links to the related topic in the e-docs "Configure a Machine to Use Node Manager."