Monitoring

UpdatedDecember 2, 2021

ByAdrian Starzynski

Java Melody

Java Melody is an open source tool for monitoring JAVA EE web applications

With this you will be able to :

monitor average response times and number of executions
make decisions before problems become too serious
optimize based on the more limiting response times
find the root causes of response times
verify the real improvement after optimizations

https://github.com/javamelody/javamelody/wiki

Configuration of Java Melody

Java Melody is already integrated in OSCAR 19, but it is disabled by default. If needed certain steps must be taken to enable and secure it’s operation. The first two settings are usually accomplished by the DEB.

1) Server must be using SSL

2) Turn on headless (add to CATALINA_OPTS)

 -Djava.awt.headless=true

3) Create a user, and add them to “monitoring” role. This is done in tomcat-users.xml. for example. This secures the monitoring to those who provide the credentials.

<role rolename="monitoring"/>
<user username="melody" password="*****" roles="monitoring"/>

4) Turn on your instance in the monitoring filter section of var/lib/tomcat8/webapps/oscar/WEB-INF/web.xml. for example so it looks like

<filter>
	   <filter-name>monitoring</filter-name>
	   <filter-class>net.bull.javamelody.MonitoringFilter</filter-class>
	   <init-param>
	   	   <param-name>system-actions-enabled</param-name>
	   	   <param-value>true</param-value>
	   </init-param>
	   <init-param>
	   	   <param-name>disabled</param-name>
	   	   <param-value>false</param-value>
	   </init-param>                           
</filter>

5) If OSCAR is not reloaded with this change, you will need to restart tomcat

Now access your server with /monitoring in the url, so for example

https://localhost:8443/oscar/monitoring

supply the username and password you set for the monitoring user

and you should see