Interested to know how people usually check to see if Tomcat is running on a Unix environment.
I either check that the process is running using
ps -ef | grep java
ps -ef | grep logging
or i check that the port number is active
netstat -a | grep 8080
is there a better way of checking that Tomcat is running? The above seem to be to be a 'hacky' way of checking that Tomcat is running.
I've found Tomcat to be rather finicky in that a running process or an open port doesn't necessarily mean it's actually handling requests. I usually try to grab a known page and compare its contents with a precomputed expected value.
netstat -lnp | grep 8080 would probably be the best way, if you know Tomcat's listening port. If you want to be certain that is is functional, you will have to establish a connection and send an HTTP request and get a response. You can do this programatically, or using any web browser.
Why grep ps, when the pid has been written to the $CATALINA_PID file?
I have a cron'd checker script which sends out an email when tomcat is down:
kill -0 `cat $CATALINA_PID` > /dev/null 2>&1
if [ $? -gt 0 ]
then
echo "Check tomcat" | mailx -s "Tomcat not running" [email protected]
fi
I guess you could also use wget to check the health of your tomcat. If you have a diagnostics page with user load etc, you could fetch it periodically and parse it to determine if anything is going wrong.
Are you trying to set up an alert system? For a simple "heartbeat", do a HTTP request to the Tomcat port.
For more elaborate monitoring, you can set up JMX and/or SNMP to view JVM stats. We run Nagios with the SNMP plugin (bridges to JMX) to check Tomcat memory usage and request thread pool size every 10-15 minutes.