NODEMANAGER

WEBLOGIC SERVER

1. Creating logical machines

2. Using nodemanager for server startup and shutdown

GETTING STARTED

Logical Machines And Node Manager

Logical machines are created for the servers so that the servers can be starting through a node manager.

In a distributed environment where servers reside on separate physical boxes, preferably the servers are started using node manager.

Machine does not really exist, it is only a logical entity.

Note: There is only one node manager per installation. This node manager can be used to start all servers in different domains of the same installation.

To create a machine from the admin console, click on Environment -> Machines

Click on lock and edit, new.

Give the name of the machine. Machine OS will be other if you are using windows.

Click Ok, and then Activate Changes.

Now click on the machine created -> Node Manager -> Node Manager Status, you will see it is in inactive state, that is because the Node Manager is not started.

Click on Configuration -> Node Manager.

Change the type from SSL to plain because we will not use the secured communication for now. Listen port is 5556 by default.

Debug if enabled, the logs will give more information about node manager request processing etc.

To add the servers in the logical machine, click on Click on Configuration -> Servers. Add the servers in the drop down list, or create more servers to be added.

Again, admin server is not preferably added to the machine. It should be only done for the managed servers.

Note: When the managed server is running, it cannot be added to the machine. It should be shutdown, else an exception is thrown.

Overview Of The Node Manager

- Node Manager can restart a Managed Server after failure even when the Administration Server is unavailable if Managed Server Independence (MSI) mode is enabled for that Managed Server instance. This is enabled by default.

- Node Manager cannot start a Managed Server for the first time in MSI mode, because the Admin Server for the domain must be available so that the Managed Server can obtain its configuration settings.

- If a server instance that was started using Node Manager fails, Node Manager automatically restarts it.

How does the Node Manager start the servers?

- When a command is initiated from the admin console to start the managed server, the admin server gives the start up properties of the managed server to the node manager. (Startup properties include classpath, jdk, jvm arguments etc)

- When these are received by the node manager, it starts the managed server

- When the managed server is starting up, it contacts the admin server for the configurations, and updates its configuration cache accordingly.

Starting the Node Manager

Before you start the node manager, go to the directory D:\BEA923\weblogic92\common\nodemanager and edit the file nodemanager.properties. – AuthenticationEnabled = false

- SecureListener = false

To start the node manager, run the script startNodeManager.cmd from the D:\BEA923\weblogic92\server\bin directory.

On the command prompt you will see that the node manager picked up the properties from the nodemanager.properties file for the startup.

<Plain socket listener started on port 5556> indicates that the node manager is started.

Confirm the node manager health from the admin console by going to the Machines -> Machine1 -> Monitoring -> Node Manager Status. It should be reachable. Unless the node manager does not come in reachable state, servers cannot be started through console.

Now click on the managed server you want to start, go to Control tab. Click start, the admin server will give the command to the node manager to start the managed server.