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Configuring and Managing WebLogic Server
Configuring Network Resources
WebLogic Server allows you to manage the connection behavior of the server instances that host applications. Configurable resources, including Network Channels and domain-wide administration ports, help you effectively utilize the network features of the machines that host your applications and manage quality of service.
The following sections describe configurable WebLogic Server network resources, examples of their use, and the configuration process:
Overview of Network Configuration
For many development environments, configuring WebLogic Server network resources is simply a matter of identifying a Managed Server's Listen Address and Listen Port. However, in most production environments, administrators must balance finite network resources against the demands placed upon the network. The task of keeping applications available and responsive can be complicated by specific application requirements, security considerations, and maintenance tasks, both planned and unplanned.
WebLogic Server allows you to control the network traffic associated with your applications in a variety of ways, and configure your environment to meet the varied requirements of your applications and end users. You can:
These and other connection characteristics can be specified by defining a Network Channel—the primary configurable WebLogic Server resource for managing network connections. You can configure a Network Channel with the Servers-->Protocols-->Channels tab in the Administration Console or by using NetworkChannelMBean.
New Network Configuration Features in WebLogic Server
In this version of WebLogic Server, the functionality of Network Channels has been enhanced to simplify the configuration process. Network Channels now encompass the features that, in WebLogic Server 7.x, required both Network Channels and Network Access Points. In this version of WebLogic Server, Network Access Points are deprecated.
Understanding Network Channels
The sections that follow describe Network Channels and the standard channels that WebLogic Server pre-configures, and discusses common applications for channels.
What is a Channel?
A Network Channel is a configurable resource that defines the attributes of a network connection to WebLogic Server. For instance, a Network Channel can define:
Rules for Configuring Channels
Follow these guidelines when configuring a channel.
Custom Channels Can Inherit Default Channel Attributes
If you do not assign a channel to a server instance, it uses WebLogic Server's default channel, which is automatically configured by WebLogic Server, based on the attributes in ServerMBean or SSLMBean. The default channel is described in The Default Network Channel.
ServerMBean and SSLMBean represent a server instance and its SSL configuration. When you configure a server instance's Listen Address, Listen Port, and SSL Listen port, using the Server-->Configuration-->General tab, those values are stored in the ServerMBean and SSLMBean for the server instance.
If you do not specify a particular connection attribute in a custom channel definition, the channel inherits the value specified for the attribute in ServerMBean. For example, if you create a channel, and do not define its Listen Address, the channel will use the Listen Address defined in ServerMBean. Similarly, if a Managed Server cannot bind to the Listen Address or Listen Port configured in a channel, the Managed Server uses the defaults from ServerMBean or SSLMBean.
Why Use Network Channels?
You can use Network Channels to manage quality of service, meet varying connection requirements, and improve utilization of your systems and network resources. For example, Network Channels allow you to:
You can also segregate instance administration and application traffic by configuring a domain-wide administration port. For more information, see Administrative Channel.
Note: Network channel weights apply only to internal connections made for remote references, such as a remote EJB reference or a resource located via JNDI. Channel weights are not used for connections initiated directly via a URL.
If you use a Network Channel with a server instance on a multi-homed machine, you must enter a valid Listen Address either in ServerMBean or in the channel. If the channel and ServerMBean Listen Address are blank or specify the localhost address (IP address 0.0.0.0 or 127.*.*.*), the server will bind the Network Channel listen port and SSL listen ports to all available IP addresses on the multi-homed machine. See The Default Network Channel for information on setting the Listen Address in ServerMBean.
WebLogic Server and the Channel Selection Process
This section describes how WebLogic selects among multiple channel to use under various circumstances.
Prioritizing Outgoing Connections
If a Managed Server has several channels that support outgoing connections, it must choose which channel to use when connecting to another server instance. WebLogic Server first selects channels based on the protocol required for the connection. If multiple channels have the same protocol support, you can prioritize those channels by assigning a different weight to each.
A channel weight is a simple numerical value that can be applied to the NetworkChannelMBean. Channel weights are considered only when multiple channels with the same service level could be used to initiate an outgoing connection. (If a channel with a higher service level is currently active, it is used regardless of channel weights). Higher-valued weights are selected over lower-weighted channels to choose a channel for outgoing connections.
In a multihomed system, channel weights allow you to prioritize equivalent channels based on the known capacity of available network cards.
Note: The default channel and administration channel, derived from values in the ServerMBean and SSLMBean, are always considered for outgoing connections, and use a default weight of 50.
Handling Channel Failures
Although WebLogic Server always attempts to use the highest-weighted channels before lower-weighted ones, a network failure may render the selected channel unavailable. To handle potential failures, WebLogic Server selects outgoing channels using the following algorithm:
This algorithm ensures that users receive a connection error message only when all channels of the required quality of service level have been exhausted. If all channel combinations are exhausted and another user attempts to initiate an outgoing connection (or a connection is retried after a failure), WebLogic Server restarts the channel selection process, starting with the highest-weighted channel.
Upgrading Quality of Service Levels for RMI
For RMI lookups only, WebLogic Server may upgrade the service level of an outgoing connection. For example, if a T3 connection is required to perform an RMI lookup, but an existing channel supports only T3S, the lookup is performed using the T3S channel.
This upgrade behavior does not apply to server requests that use URLs, since URLs embed the protocol itself. For example, the server cannot send a URL request beginning with http:// over a channel that supports only https://.
Standard WebLogic Server Channels
WebLogic Server provides pre-configured channels that you do not have to explicitly define.
The Default Network Channel
Every WebLogic Server domain has a default channel that is generated automatically by WebLogic Server. The default channel is based on the Listen Address and Listen Port defined in the ServerMBean and SSLMBean. It provides a single Listen Address, one port for HTTP communication (7001 by default), and one port for HTTPS communication (7002 by default). You can configure the Listen Address and Listen Port using the Configuration-->General tab in the Administration Console; the values you assign are stored in attributes of the ServerMBean and SSLMBean.
The default configuration may meet your needs if:
Using the default configuration ensures that third-party administration tools remain compatible with the new installation, because network configuration attributes remain stored in ServerMBean and SSLMBean.
Even if you define and use custom Network Channels for your domain, the default channel settings remain stored in ServerMBean and SSLMBean, and are used if necessary to provide connections to a server instance.
You can define an optional administration port for your domain. When configured, the administration port is used by each Managed Server in the domain for communication with the domain's Administration Server.
Administration Port Capabilities
An administration port provides these capabilities:
If a administration port is enabled, WebLogic Server automatically generates an Administration Channel based on the port settings upon server instance startup.
Administration Port Restrictions
The administration port accepts only secure, SSL traffic, and all connections via the port require authentication. Because of these features, enabling the administration port imposes the following restrictions on your domain:
Administration Port Requires SSL
The administration port requires SSL, which is enabled by default when you install WebLogic Server. If SSL has been disabled for any server instance in your domain, including the Administration Server and all Managed Servers, re-enable it using the Server--> Configuration-->General tab in the Administration Console.
Ensure that each server instance in the domain has a configured default listen port or default SSL listen port. The default ports are those you assign on the Server-->Configuration-->General tab in the Administration Console. A default port is required in the event that the server cannot bind to its configured administration port. If an additional default port is available, the server will continue to boot and you can change the administration port to an acceptable value.
By default WebLogic Server is configured to use demonstration certificate files. To configure production security components, follow the steps in "Configuring the SSL Protocol" in Managing WebLogic Security.
Configure Administration Port
Enable the administration port as described in "Enabling the Domain-Wide Administration Port" in Administration Console Online Help.
After configuring the administration port, you must restart the Administration Server and all Managed Servers to use the new administration port.
Booting Managed Servers to use Administration Port
To reboot Managed Servers to connect to the Administration Server's administration port, the command line or start script must specify the https:// prefix, rather than http://, as shown below.
If the hostname in the URL is not identical to the hostname in the Administration Server's certificate, disable hostname verification in the command line or start script, as shown below:
Custom Administrative Channels
If the standard WebLogic Server Administrative Channel does not satisfy your requirements, you can configure a custom channel for administrative traffic. For example, a custom administrative channel allows you to segregate administrative traffic on a separate NIC.
To configure a custom channel for administrative traffic, configure the channel as described in Configuring a Channel, and select "admin" as the channel protocol. Note the configuration and usage guidelines described in:
Configuring a Channel
You can configure a Network Channel using Servers-->Protocols-->Channels tab in the Administration Console or using the NetworkChannelMBean.
For instructions to configure a channel for a non-clustered Managed Server, see "Configuring a Network Channel" in Administration Console Online Help. To configure a channel for clustered Managed Servers see, Configuring Network Channels with a Cluster.
For a summary of key facts about Network Channels, and guidelines related to their configuration, see Configuring Channels: Facts and Rules.
Configuring Channels: Facts and Rules
Follow these guidelines when configuring a channel.
HTTP is enabled by default when you create a channel, because RMI protocols typically require HTTP support for downloading stubs and classes. You can disable HTTP support on the Advanced Options portion of Servers-->Protocols-->Channels tab in the Administration Console.
Configuring Network Channels with a Cluster
To configure a channel for clustered Managed Servers, note the information in Configuring Channels: Facts and Rules, and follow the guidelines described in the following follow.
Create the Cluster
If you have not already configured a cluster you can:
For information and guidelines about configuring a WebLogic Server cluster, see "Before You Start" in Using WebLogic Clusters.
Create and Assign the Network Channel
Use the instructions in "Configuring a Network Channel" in Administration Console Online Help to create a new Network Channel for each Managed Server in the cluster. When creating the new channels: