WebLogic Server 12c - PerDomain Node Manager Configuration Model

Let's start with giving a brief definition of Node Manager. 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 server instances from a remote location. Node Manager is optional but it is recommended if your WebLogic Server environment hosts applications with high availability requirements.

WebLogic Server 12c has over 200 new features. One of these features is a new Node Manager configuration model. In WebLogic 12c, the Java version of Node Manager has a simplified, out-of-the-box configuration. Node Manager is moved from PerHost configuration to PerDomain configuration model. The Install Windows Service screen, which provided the option to install Node Manager as a service on Windows systems, is no longer included.

In WebLogic 12c for each domain you create, an instance of domain-specific Node Manager is created/configured by default. With this default configuration, using the security credentials supplied for the Administration Server, nm_password.properties is created in DOMAIN_HOME\config\nodemanager. We can use Configuration Wizard or WLST tools to create Domain/Node Manager configuration. We can select a PerDomain or CustomLocationJava-based Node Manager configuration model. The PerDomain configuration is exactly as described for the default configuration, except that it allows you to provide unique Node Manager credentials. If you want a seperate location for NodeManagerHome, select CustomLocation and specify an empty directory or select to create one. The resulting Node Manager also runs as a per domain process.

After the default installation, the nodemanager.properties and nodemanager.domains files are created for you under DOMAIN_HOME\nodemanager and domain-specific scripts to start, stop, install and uninstall Node Manager as a Windows service, are created under DOMAIN_HOME\bin. With the default Node Manager configuration, you cannot edit the NodeManagerHome location, in this case it will be DOMAIN_HOME\nodemanager.

Let's see the process step by step. I will use the configuration wizard tool to create a sample domain. After starting the wizard and proceeding for the first few steps you will be prompted to choose the components to modify/create. Here you can select Node Manager option to configure some of it's properties like Node Manager type, Node Manager username and password, and Node Manager location.

On the next screen we can modify the following properties;

Node Manager Type:

Per Domain: If you select this option, the Node Manager home is predefined within the domain as <domain_name>/nodemanager and you cannot edit the Node Manager home. 

Custom Location: Select this option if you want the Node Manager configuration files to be created in a specific location for this domain. Specify the directory in the Node Manager Home field, or click Browse to navigate to the location. The specified directory must be empty. The nodemanager.properties and nodemanager.domains files will be created in this directory. 

Manual Node Manager Setup: If you select this option, creation of the Node Manager configuration for the domain is skipped, and you must manually create and update the Node Manager configuration for the domain.

Node Manager Credentials: Here you enter the username and password for this Node Manager instance.

After the wizard exits, we will have the following folder structure and the Node Manager related configuration files. 

Please remember you can still use Per Host Node Manager (scripts are located in WL_HOME\server\bin). However there is extra step you must take to use this model. Below is the summary of this steps;

1. Create a nodemanager.domains file that specifies the domains that you want this Node Manager instance to control, under     ORACLE_HOME\oracle_common\common\nodemanager, the per host NodeManagerHome location.

2. Generate a certificate and private key to communicate with Node manager over SSL