About Nodemanager In Weblogic

About Nodemanager In Weblogic

Node Manager is a WebLogic Server utility that enables you to start, shut down, and restart Administration Server and Managed Server instances from a remote location.

A Node Manager process is not associated with a specific WebLogic domain but with a machine.
You can use the same Node Manager process to control server instances in any WebLogic Server domain, as long as the server instances reside on the same machine as the Node Manager process.
Node Manager must run on each computer that hosts WebLogic Server instances whether Administration Server or Managed Server that you want to control with Node Manager.

WebLogic Server provides two versions of Node Manager, Java-based and script-based, with similar functionality. However, each version has different configuration and security considerations.

Java-based Node Manager

Java-based Node Manager runs within a Java Virtual Machine (JVM) process.
This version of Node Manager determines its configuration from the nodemanager.properties file.
Java-based Node Manager provides more security than the script-based version.

Script-based Node Manager

For UNIX and Linux systems, WebLogic Server provides a script-based version of Node Manager.
This script is based on UNIX shell scripts, but uses SSH for increased security. SSH uses user-id based security
This version does not provide as much security as the Java-based version.
The advantage of the script-based Node Manager is that it can remotely manage servers over a network that has been configured to use SSH. No additional server installation is required. The scripts merely have to be copied to the remote machine.

Q)What You Can Do with Node Manager

Start, Shut Down, and Restart an Administration Server
Start, Shut Down, Suspend, and Restart Managed Servers
Monitor Servers and View Log Data

Starting Java-based Node Manager
Start scripts for Node Manager are installed in the WL_HOME\server\bin directory, where WL_HOME is the top-level installation directory for WebLogic Server.
Use startNodeManager.cmd on Windows systems and startNodeManager.sh on UNIX systems.
The scripts set the required environment variables and start Node Manager in WL_HOME/common/nodemanager. Node Manager uses this directory as a working directory for output and log files.

Note:
You can use the same nodemanager process to control server instances in any WebLogic Server domain, as long as the server instances reside in same machine as the Node Manager Process.

Q)Node Manager Types
Basically, there are 4 types of node managers available in weblogic
PLAIN
SSL
SSH
RSH

Accessing the Node Manager
You can access the Node Manager from the following clients:
Administration Console - From the Environments -- Machines -- Configurations-- Node Manager (Tab)

Q)Important Node Manager Configuration Files ?

-nodemanager.properties
This is the configuration file used by the Java-based version of Node Manager.
This file is located in WL_HOME/common/nodemanager.

-nodemanager.hosts
This file contains a list of all the trusted hosts that can issue commands to Node Manager.
This file is located in WL_HOME/common/nodemanager.

-nodemanager.domains
This file contains mappings between the names of domains managed by Node Manager and their corresponding directories.
This file is located in WL_HOME/common/nodemanager.

-nm_data.properties
This file stores the encryption data the Node Manager uses a symmetric encryption key. The data is stored in encrypted form.
This file is located in WL_HOME/common/nodemanager.

-nm_password.properties
This file stores a username/password pair specific to the Node Manager server that is managing this domain. This is known as the Node Manager secret. The username and password are appended to a salt value (obtained from the SerializedSystemIni.dat of the domain) and SHA-hashed.

This file is located in DOMAIN_HOME/config/nodemanager.

-boot.properties
Node Manager uses this file to specify a boot identity when starting a server. This file is located in domain-name/servers/server_name/data/nodemanager.

-startup.properties
Each Managed Server instance has its own startup.properties file with properties that control how Node Manager starts up and controls the server. Node Manager automatically creates this file by using properties passed to Node Manager when the Administrative Server was last used to start the server. This allows a Node Manager client or startup scripts to restart a Managed Server using the same properties last used by the Administrative Server.
These properties correspond to the server startup attributes contained in ServerStartMBean and the health monitoring attributes in ServerStartMBean.

-server_name.addr
This file is located in domain-name/servers/server_name/data/nodemanager.
server_name.addr stores the IP address added when a server starts or is migrated. This file is generated after the server IP address is successfully brought online during migration. server_name.addr is deleted when the IP address is brought offline. The server IP address is used to validate remove requests to prevent addresses being erroneously removed while shutting down the server.
This file is located in domain-name/servers/server_name/data/nodemanager.

-server_name.lck
server_name.lck is generated by each server and contains an internally used lock ID.