5.3.4 Developer Tips

General Tips

• Order of startup and shutdown of Modules in Web NMS

• Dependency between Web NMS Modules

• How to reduce the time taken to check for web server connection during server startup?

• I want to start Web NMS based on the result of our Business Logic. If the result of our logic is positive, we would start the Web NMS. Otherwise, we would stop the server.  In short, we want to have a handle which would enable us to control server startup before the initialization of the processes. Is there any utility to achieve this requirement?

• When there are more than one NIC card, the IP address that the Web NMS should pick when starting the client. How to provide the entry in startnms.bat for this scenario.

• How to disable the creation of tables on starting the server.

Trouble Shooting Tips

• My module does not get started

• Arguments specified for the module are not proper

• Web NMS server hangs during startup

• I am getting a java.rmi.ConnectException while shutting down Web NMS Server using the ShutDownAPI from a remote JVM. Why ?

General Tips

• Is there any specific order in which the modules of Web NMS get Started and shut down?
  
  When the Web NMS BE and FE servers are running in separate JVMs, they obey the rules of the Module Services in the order of starting up and shutting down the modules specified in the respective configuration files.
  
  When they both run in the same JVM, during server startup the BE modules are started first followed by the FE modules. During server shutdown, the FE modules are shutdown first followed by the BE modules.  The startup and shut down operations obey the ordering specified in the respective configuration files. In case, a module is specified to be plugged in both the BE and FE servers (has an entry in both NmsProcessesBE.conf and NmsProcessesFE.conf) then only the entry specified in the NmsProcessesBE.conf will be taken.

• Is there any document which explains the dependency between Web NMS Modules/Processes?
  
  Yes. The document titled "Dependency between Web NMS Modules"

• lists down the processes which are mandatory for the functioning of Web NMS

• lists the processes needed by each of the services offered by Web NMS

• brings out the dependency between various processes/services

• lists the processes that can be enabled/disabled on need basis

Note: The terms 'Modules' and 'Processes' mean the same and are used interchangeably.

• How to reduce the time taken to check for web server connection during server startup?

Edit startnms.bat/sh script file located in the <Web NMS Home>/bin directory and add a system property -Dwebcontainer.port="% WEBCONTAINER_PORT%" for NmsMainBE JVM instance and then start the Web NMS server.

Example:

%JAVA_HOME%\bin\java -cp %CLASS_PATH% -Dcatalina.home=%TOMCAT_HOME% -Dmysql.home=%MYSQL_HOME% -Dwebserver.port=%WEBSERVER_PORT% -Xmx100m -Dresource_check="%WEBSERVER_PORT%,%WEBCONTAINER_PORT%,%TOMCAT_SHUTDOWNPORT%" -Dwebcontainer.port="% WEBCONTAINER_PORT%" -Dwebserver.rootdir=%WEBSERVER_HOME% -Djava.rmi.server.codebase=%CODEBASE_LIST% com.adventnet.nms.startnms.NmsMainBE NMS_BE_PORT 2000 ROOT_DIR %NMS_HOME% NATIVE_PING true

[Note: All in a single line]

• I want to start Web NMS based on the result of our Business Logic. If the result of our logic is positive, we would start the Web NMS. Otherwise, we would stop the server.  In short, we want to have a handle which would enable us to control server startup before the initialization of the processes. Is there any utility to achieve this requirement?
  
  
  You can achieve this requirement by using the Pre-startup Hook provided by Web NMS.
  
  Web NMS provides an interface named 'StartupAction'. This interface provides the prestartup hook. Using this interface, you can get the handle of the server. During server startup, prior to the initialization of the processes, you can internally handle starting or stopping of the server.
  
  For getting the prestartup hook, you need to do the following:
  
  1. Write a class implementing the interface StartUpAction
  2. In that custom class, you need to overwrite the method "handleStartUp(Map map)".
  3. Make an entry in the nmsinterfaces.conf file mentioning the name of your custom class as shown below:
        StartUpAction="Your class name"
  4. Inside the handleStartUp method, you can handle your own business logic and depending upon the result, you can start or stop the server.
  
  To Start the server:
  
  Return the interger value  StartUpAction.CONTINUE to start the server.
  
  To Stop the server:
  
  Return the interger value StartUpAction.ABORT to stop the server.
  
  (Web NMS internally calls the handleStartUp method of your class before initializing the processes).
  
  5. The method handleStartUp will provide the java.Util.Map object as an argument. This Map object contains the parameter isPrimary. If the role of the server is primary, the value for this parameter will be "true", else "false".
  
  This pre-starup hook can be used in our failover mechanism as a failover hook also. Using this hook, you can decide at runtime if your Standby has to start or stop after the failure of the Primary.
   

• When there are more than one NIC card, the IP address that the Web NMS should pick when starting the client. How to provide the entry in startnms.bat for this scenario.

When there are more than one NIC card, the IP address that the Web NMS should pick when starting the client can be provided with the "-Dnms.server.host" parameter.  An example startnms.sh/bat entry is as follows:
 

%JAVA_HOME%\bin\java -cp %CLASS_PATH% -Dcatalina.home=%TOMCAT_HOME%
-Dmysql.home=%MYSQL_HOME% -Dwebserver.port=%WEBSERVER_PORT% -Xmx100m
-Dresource_check="%WEBSERVER_PORT%,%WEBCONTAINER_PORT%,%TOMCAT_SHUTDOWNPORT%"
-Dwebserver.rootdir=%WEBSERVER_HOME% -Djava.rmi.server.codebase=%CODEBASE_LIST%
-Dnms.server.host=192.168.9.14 com.adventnet.nms.startnms.NmsMainBE NMS_BE_PORT 2000 ROOT_DIR %NMS_HOME% NATIVE_PING true 

• How to group devices in the Home Page of Web Client?

When writing a device-specific map filter, setting a property  HTML-TABLE, creates a separate group. The property setting is shown below:

p.put("HTML-TABLE","Infrastructure View");

The device is grouped under Infrastructure View in the tree.
 

• How to modify the Alarm Graph (Bar chart) in the Home page of Web Client?
  
  Adding the category node in <WebNMS Home>/conf/ACCCategoryInfo.xml  displays the category as bar chart in home page. See example entry given below:
  
  <CATEGORY Name="Public">
  </CATEGORY>

• How to disable the creation of tables on starting the server.

The creation of tables can be disabled by setting the system property disable-schema-creation for NmsMainBE in startnms.bat as true.

-Ddisable-schema-creation=true

Troubleshooting Tips

• My module does not get started
  
  Check if the CLASSPATH variable set for the Web NMS server includes the classpath where your implementation of RunProcessInterface is present (the fully qualified class name given in the configuration file.)

• Arguments specified for the module are not proper
  
  Every PROCESS entry in the NmsProcesses[BE/FE].conf file must also have a corresponding ARGS entry. If your module does not need to take any parameters, still you should have the ARGS entry with a "NULL" against it (ARGS NULL). Otherwise, the configuration file will not be parsed properly and all the entries following this mismatch will not take effect.

• Web NMS server hangs during startup
  
  Check if your implementation of the isInitialized method indeed returns true in finite time. The Web NMS server waits for all the module's isInitialized methods to return true as part of its startup process.

• I am getting a java.rmi.ConnectException while shutting down Web NMS Server using the ShutDownAPI from a remote JVM. Why?
  
  You are getting this exception since RMI Registry is also killed during the shut down process. As a result, a ConnectException is thrown at the end of shutdown process. This exception is harmless and can be ignored.