The document explains the process of creating and managing logical machines in a WebLogic Server environment using Node Manager, which allows server startup and shutdown in a distributed setup. It details steps for configuring Node Manager, including setting properties, adding servers, and how Node Manager interacts with the admin server for server management. Additionally, it highlights Node Manager's ability to automatically restart managed servers and the conditions under which these operations can occur.

1. NODEMANAGER
WEBLOGIC SERVER

2. 1. Creating logical machines
2. Using nodemanager for server startup and
shutdown
GETTING STARTED

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. Starting the Node Manager
Before you start the node manager, go to the directory
D:BEA923weblogic92commonnodemanager and edit the file nodemanager.properties. –
AuthenticationEnabled = false
- SecureListener = false
To start the node manager, run the script startNodeManager.cmd from the
D:BEA923weblogic92serverbin directory.
On the command prompt you will see that the node manager picked up the properties from
the nodemanager.properties file for the startup.

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

11. 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.

12. 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.