Monitoring and managing Apache Tomcat

Monitoring is a key aspect of system administration. Looking inside a running server, obtaining some statistics or reconfiguring some aspects of an application are all daily administration tasks.

You always should monitor a Java application you deployed with Tomcat so here is a quick configuration cheatsheet about Tomcat 8.

Enable JMX remote monitoring

Add the following parameters to setenv.bat or setenv.sh script of your Tomcat:

set CATALINA_OPTS=-Dcom.sun.management.jmxremote
  -Dcom.sun.management.jmxremote.port=%my.jmx.port%
  -Dcom.sun.management.jmxremote.ssl=false
  -Dcom.sun.management.jmxremote.authenticate=false

If you require authorization, add and change this:

  -Dcom.sun.management.jmxremote.authenticate=true
  -Dcom.sun.management.jmxremote.password.file=../conf/jmxremote.password
  -Dcom.sun.management.jmxremote.access.file=../conf/jmxremote.access

edit the access authorization file $CATALINA_BASE/conf/jmxremote.access:
```
monitorRole readonly
controlRole readwrite
```
edit the password file $CATALINA_BASE/conf/jmxremote.password:
```
monitorRole tomcat
controlRole tomcat
```
Tip: The password file should be read-only and only accessible by the operating system user Tomcat is running as.