Monitoring MemberzPlus
for the Low Level Administrator

By remotely monitoring a running MemberzPlus™, we can find out all kinds of things about the application such as detect memory leaks, identify resource intensive processes, etc. Real-time monitoring of a running Java Virtual Machine (JVM) was not recommended in the past because it was just too instrusive and could occasionally cause the JVM to crash. That is no longer the case. Now there is no reason not to set up the production environment so it can be monitored. That way, if an issue does arise, it's easy enough to fire up a tool like VisualVM to take a look and see what's going on.

The only setup in JBoss is to define the responding port and the security for accessing that port. Basically, the monitoring tools connect to the running JBoss through a TCP port configured at startup. You can also limit that connection to SSL/TLS and/or a username/password authentication. The raw system properties involved are:

com.sun.management.jmxremote.port

Set the JVM listening port which must be unique per IP address. Typically, you can reference an environment variable in the run script and then set it in the FireDaemon configuration.

com.sun.management.jmxremote.ssl

Set to "true" or "false." If "true," the other SSL-related settings are required.

com.sun.management.jmxremote.authenticate

Set to "true" or "false." If "true," then the username and password settings are required. Ross Group highly recommends requiring both SSL and authentication for any production environment. For more information, see http://download.oracle.com/javase/6/docs/technotes/guides/management/agent.html

java.rmi.server.hostname

In the event that you can't get DNS resolution to the remote server you are monitoring, you MUST set this on the server so that it refers to itself by IP instead of by hostname. This does have the potential to cause issues with other third party apps; however, we haven't yet had an issue in a MemberzPlus™ environment.

jstatd

Run "jstatd" (located in the Java /bin directory) on the server. It serves as a bridge between VisualVM (or other tools) and the JVM. First, you need to create security policy file, for instance "tools.policy", for jstatd's JVM containing:

grant {
permission java.security.AllPermission;
};

Then, you can jstatd:

jstatd -J-Djava.security.policy=tools.policy

The policy file tells the running jstatd JVM to allow external programs to connect to it for monitoring.