04. NodeManager in WebLogic 12c

WebLogic 12c Node Manager

Node Manager

• Describe the architecture and capabilities of the Node Manager
• Create a Node Manager with the Configuration Wizard
• Configure properties for the Java Node Manager
• Describe the Java Node Manager directory structure
• Enroll a Node Manager with a domain
• Start and stop a Node Manager
• Start and stop managed servers by using the Administration Console

New features in WebLogic 12c are listed here:

1. Node Manager can be available in per domain and per machine. As per the best practices for development environment or production if you have multiple WebLogic domains in the same machine without disturbing other business functionality better to use per domain node manager. If  3 or 4 domains associated with same business then better to use per machine node manager. 
2. Up to WebLogic 11g we don't have stop node manager script, but in 12c you can see this in the bin directory of Domain!

In WebLogic we have two different versions of Node Manager, while you configuring your machine you will be asked 'Unix' or 'Other' type machine.

There are 2 versions of the Node Manager:

• Script based 
• Java based

Script-based Node Manager 
Typically for *NIX-like systems, WebLogic provides a Node Manager script to start the Node Manager. This is less secure than the Java-based version. However, 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.

Java-based Node Manager 
The Java-based Node Manager runs as an O/S Java Virtual Machine process. On Windows, you can install it as a service using the installNodeMgrSvc.cmd. You should configure the port and listen address in this script. An important configuration file is the nodemanager.properties, located in the /common/nodemanager. 
An important thing to do is to set the properties StartScriptEnabled and StopScriptEnabled to true. When the Node Manager starts on a WebLogic Server, it will now use the startWebLogic script. This script calls the setDomainEnv.sh (setWLEnv.sh) script, which sets the server's classpath. If you leave this to false, starting the WebLogic Server instance might not be successful as key components fail to start because of classpath errors. Another interesting parameter you might want to set is CrashRecoveryEnabled.You can set this to true when you want a Managed Server to be restarted when it has crashed. 

1. Create a Machine in the AdminConsole or during domain creation, and attach your servers to it. 
2. Startup the Node Manager in the foreground: $WL_HOME/server/bin/startNodemanager.sh The property file and domains file will be created in: /common/nodemanager. Edit the nodemanager.properties for your needs, such as StartScriptEnabled and StopScriptEnabled, CrashRecoveryEnabled,and ListenAddress. 
3. On *NIX: 1. Create a Machine in the AdminConsole or during domain creation, and attach your servers to it. Use a UNIX Machine for *NIX systems, "Other" for Windows. 2. Start up the Node Manager in the foreground:

   $WL_HOME/server/bin/startNodemanager.sh

   The property file and domains file will be created in WL_HOME/common/nodemanager. Edit the nodemanager.properties for your needs, such as StartScriptEnabled and StopScriptEnabled, CrashRecoveryEnabled, and ListenAddress. 3. Now start the Node Manager in the background: 

nohup $WL_HOME/server/bin/startNodemanager.sh &  

Here I found 3 interesting exam questions which are related to Node Manager.
Which actions can you perform using the WebLogic Admin Console?

1. Stop and start managed servers using the Node manager
2. Create and target JDBC connection pools, stop and start coherence servers using the nodemanager.
3. Create a WebLogic domain template
4. Create and target WebLogic diagnostic framework diagnostic modules.

You installed WebLogic, SOA Suite and Oracle service bus on a machine and want to use the weblogic node manager to start server for each product. Which statement is true?

1. You need to install a separate node manager for each middleware home that has a unique major and minor WebLogic version number.
2. You need to install and configure only one instance of Node Manager for all products, regardless of the weblogic version number
3. You need to install and configure a separate node manager for each domain of each product you want to run on the machine.
4. You need to install one Node manager but use separate SSL certificates for each product when searching the network communication to the machine

WebLogic 12c is having best features Node Manager. This 12c release allows you to create Node Manager per node, per domain. If all of the Oracle softwares working for the same business then better to use one instance of Node Manager.The Node Manager is enhanced for starting/stopping Coherence cache
servers from the Administration Console or doing it remotely.

Node Manager Optimal usage

You want to configured WeLogic so that Managed Servers are restarted when they are in FAILED state. Which three steps are necessary to accomplish this?

1. Configure Node manager on the manchines where WebLogic managed servers need to be started/restared.
2. Enable auto restart in the nodemanager configuration
3. Enable auto kill if failed for the managed server in question
4. Enable Auto restart for the managed servers in question

What would be answer for this???????

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Introduction to Nodemanager

Server instances in a WebLogic Server production environment are often distributed across multiple domains, machines, and geographic locations. 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. You can use Node Managers to:

•  Start, shut down, and restart an Administration Server
•  Start, shut down, suspend, and restart Managed Servers 
• Automatically restart the Administration and Managed Servers on failure
•  Monitor servers and collect log data

Node Managers:

•  Run on the same computers as the Managed Servers
•  Can be run automatically in the background as Windows services or UNIX daemons •
•  Are available as either Java-based, or script-based processes (for UNIX only) 
• The idea is that the 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 WebLogic Server instances in any WebLogic Server domain, as long as the server these instances reside on is the same machine as the Node Manager process. The Node Manager process must run on each server that hosts WebLogic server instances—Administration or Managed Server—that you want to control with Node Manager.

Some important things to know:

•  Configurations are stored under the /common/nodemanager in the nodemanager. Properties
• The domains controlled by the Node Manager are stored in the nodemanager.domains file in that same directory 
• Domain-specific configurations are stored in the domain directory under servers// startup.properties 

Within Windows, Node Manager can run as a service. Under Linux/UNIX, there's no out-of-the-box daemon configuration available, so you will have to create that yourself .For this, there is an installation script available, which is installNodeManagerSvccmd.

Versions of Node Manager

There are 2 versions of the Node Manager:

• Script based 
• Java based

Script-based Node Manager Typically for UNIX-like systems, WebLogic provides a Node Manager script to start the Node Manager. This is less secure than the Java-based version. However, 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.