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Tag Archive jmx

We received some alerts tonight that one Tomcat server was using about 95% of its configured thread maximum.

The Tomcat process on http-443  on prod4 now has 96.2 %
of the max configured threads in the busy state.

These were SMS alerts, as that was close enough to exhausting the available threads to warrant waking someone up if needed.

The other alert we got was that Tomcat was taking an unusual time to process requests, as seen in this graph: Read more »

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The many faces of JMX monitoring

Posted by & filed under Uncategorized .

We like monitoring. We like Java. Not to slight other languages – we like Ruby, perl, php, .NET and other platforms, too, and like to monitor them, also.

However, unlike most other languages, Java provides an explicit technology for monitoring applications and system objects.   JMX is supported on any platform running the JVM, but like most other monitoring protocols, there are lots of interesting nuances and ways to use it. Which means lots of nuances in how to detect it and monitor it.

We have quiet a few customers that use LogicMonitor for JMX monitoring, of both standard and custom applications, so we’ve run into quite a few little issues, and solved them.

One example is that the naming convention for JMX objects is loosely defined.  Initially, the JMX collector for LogicMonitor assumed that every object would have a “type” key property, as specified in best practices. Of course, this is a rule “more honored in the breach than in the observance”, as widespread applications such as WowzaMediaServer and even Tomcat do not adhere to it.

Another example is that JMX supports complex datatypes.  We have customers who do not register different Mbeans for all their classes of data, but instead expose Mbeans that return maps of maps. Our collectors and ActiveDiscovery did not initially deal with these datatypes, as we hadn’t anticipated their use.  But, there are good reasons to use them in a variety of cases, so LogicMonitor should support the wishes of the user – that’s one of our tenets, that LogicMonitor enables user’s to work the way they want, instead of constraining them to a preconceived idea.  So we extended our ActiveDiscovery to iterate through maps, and maps of maps, and composite datatypes.

This enables our customers to instrument their applications in the way they think is most appropriate, while automating the configuration of management and alerting.  While we think we’ve got all the permutations of JMX covered, I’m not taking any bets that a new customer won’t come along with a new variant that adds a perfectly logical use case that we do not support.  Of course, if that’s the case, we’ll support it within a month or so – and all our customers – current and future – will be able to immediately reap the benefits. That’s just one of the niceties of the hosted SaaS model.

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