I think you need a multilayer system :-) 1) a http-client app which simply calls the same simple servlet (simply writing "available" in the response or something like this) each 10 seconds and check if the server replies at all.
2) monitor cpu load on the machine. If the idle time is 100% the tomcat is probably dead (This of course expects some continious load on the server) 3) monitor the logs 4) your simple servlet from 1) could deliver current free memory and the monitoring application could raise alerts if the amount decreases (still, would be harder to get PermGenSpace) Leon P.S. btw, an outofmemory in the permgenspace doesn't necessary mean an OutOfMemory in the logs. The AllThreadsBusy message also happens because an OutOfMemory. Or any other "strange" log messages. We had this situation (running of permspace) some time ago, and the errors were everything but logical: response already commited exceptions or bean xyz not found for example. regards Leon On 6/12/06, Peter Neu <[EMAIL PROTECTED]> wrote:
You are right Leon. I just did a field test on our test server. The perm gen space is relatively small on that machine. So opened a lot sessions and did a lot of XSLT/FOP/Excel generation. Thus the perm gen space was spent very fast. I monitored this with lambda. In the end the server did not respond anymore. And here comes the frightening news. There is no trace in the log files for that problem. So it is safe to say when the server does not respond in say 2 minutes the game is over. One question remains after all. Doesn't it pay off to simply look ater the Memory space in frequent intervalls to see it bottle neck is ahead? I mean it's possible to define certain ranges. Any ideas? Cheers, Swen -----Ursprüngliche Nachricht----- Von: Leon Rosenberg [mailto:[EMAIL PROTECTED] Gesendet: Montag, 12. Juni 2006 14:22 An: Tomcat Users List Betreff: Re: Detect tomcat problems with a custom java reporting apps? I'm not sure that after something "bad" happens you can access the server at all. An OutOfMemory or an AllThreadsBusy Exception normally lead to a non-responding tomcat. The best thing you could do is monitoring the logs with a separate script on the same machine and send mails on failure imho. regards leon p.s. for the application monitoring of your production server you should try moskito :-) On 6/12/06, Peter Neu <[EMAIL PROTECTED]> wrote: > Yes, I am using this already. But there is some vital functionality missing. > > When an java.lang.outOf.MemoryException happens I won't get an alert unless > I happen to be using lambda at the moment. So what we have at hand is a > 'Schrödinger Cat' situation. > > I need to monitor the jmx control layer and have my program send out alerts > when something bad happens. > > So far I have 2 problems: > > 1. How do I find an error? I played around with the JMX Proxy Servlet. There > is this Mbean: MemoryPool. When I query this I get the following result: > > Name: java.lang:type=MemoryPool,name=Perm Gen [shared-rw] > modelerType: sun.management.MemoryPoolImpl > Type: NON_HEAP > CollectionUsageThreshold: 0 > CollectionUsageThresholdExceeded: true > MemoryManagerNames: [Ljava.lang.String;@943129 > CollectionUsageThresholdSupported: true > ..... > > If I see this I can't tell if anything is wrong. So what to do? > > 2. How do I access the jmxproxy servlet from a java app? It requires > authentication. :o( > > Cheers, > Pete > > > > > > > --------------------------------------------------------------------- > To start a new topic, e-mail: users@tomcat.apache.org > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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