Monitor and administer Apache Tomcat with Lambda Probe

If you want to monitor and administer web applications that’re running inside Apache Tomcat you should have a look at Lambda Probe: it’s a small WAR that can be dropped inside your Tomcat instance and once you’ve done that you can use it to perform administrative tasks.


The installation for Lambda Probe is pretty easy: download probe.war and copy it to $CATALINA_HOME/webapps/.

Once you’ve done that make sure that the user tomcat has the role manager. Have a look at your tomcat-users.xml file:

  <role rolename="manager"/>
  <role rolename="poweruser"/>
  <role rolename="poweruserplus"/>
  <role rolename="probeuser"/>
  <user name="tomcat" password="tomcat" roles="manager" />

You can use the other roles to configure access to Lambda Probe. Have a look at this page if you want to do that.

If you want to have a look at the memory graphs and everything JMX related you’ll have to enable JMX Remote. This comes down to these lines:


That’s it. Now you’re ready to use Lambda Probe.


If you want to monitor and administer web applications inside Apache Tomcat, Lambda Probe seems to be a very nice solution. I recommend to definitely give it a try.

Update: There’s a pretty active fork of Lambda Probe called PSI Probe around. I recommend using this instead.


  • Bertrand Gourraud says:

    I really want to give a try to Lambda probe but unfortunately the Lambda probe web site seems to be unavailable. Do you know another location where I could download this tool?

  • Lawrence says:
    If you want the application then send me a mail and I will send you a link where you can download it from.


  • Claus Seitter says:
    could you please send me a link where to download the war (and the sources) after has vanished ?
    Thanx a lot!
  • Naresh says:
    Could you also send me the link where to download the war file from?

    Thank you so much.

  • Régis says:

    Could you send me the link to download the war file ?
    Very big thanks

  • Robin Mannering says:

    Could you also send me the same link. Their site still seems unreachable. Many thanks for your time

  • Hi everybody, is up and you can download the WAR and the source code again.

  • Ahsan says:
    can any body share the documentation for the lembda probe ,
  • David says:
    Just for information, when setting could be acceptable on test/dev servers, it is pretty unsecure for production. Read this.
  • Hi David,
    thanks you for the hint, I’ll integrate it into the article. Nevertheless, I wrote these instructions for the impatient 😉
  • Kai says:
    Hi Christian, thank you for the instruction, and I hope you don’t mind me asking a question here. I followed the instruction from above (and reference a few others), download the .war file and put it in D:\Tomcat 6.0\webapps\probe.war . Then I modified the D:\Tomcat 6.0\conf\tomcat-users.xml by adding a user named “tomcat” and assigned it the manager right. I restarted the Apache Tomcat service, then it returns a http 404 error. the requested source is not available. is there anything that I’d done wrong that makes the site unable to display? Thank you very much
  • stew says:
    Hi There

    Is the website having issues again and if so can you send me a link to where I may access Lambda Probe, many thanks

  • Hi Stew,
    you can download the WAR here.
  • Kevin says:
    Did you ever get your probe working. Mine works on local server, but It will not work from any client connected to it.
  • Mamtha says:

    Could you send me the link to download the war file ?
    Very big thanks

  • Priya says:

    Can we use tomcat probe to monitor multiple instances? If so can you please tell me how do i need to use the war in each instance?

  • Hi Priya,
    you can’t monitor multiple instances with a single installation but you’ll have to deploy Lambda Probe in every Tomcat that you’d like to monitor. Just place the WAR file into the webapps directory and open Lambda Probe’s web frontend in your browser. You can learn more about the installation here.
  • Ruben says:
    Thk Christian Schenk !!! ..
  • Gazzola says:
    How configure file to probe?
  • Hi Gazzola,
    please check out the website for PSI Probe and you’ll find an installation manual there. This should help you getting it configured in case the above howto is missing something.