AND crontab say 5 min later..launches this java programme, which will restart tomcat..this is not a thread..just a java programme...that is the reason I am trying to launch it from crontab...
When jvm crashes it writes its report..and goes away from the memory..You can still launch a java programme after this crash (like launching tomcat again after the crash)..
..
--tomcat running
--jvm crashes..
--crontab launches my watcher (written in java)
--my application checks if tomcat is running...and restarts is necessary..
--if my programme is running at the time of crash..my programme crashes too...but 5 min later my programme is activated by crontab again..
Am I missing something here?
Take care..
Ayhan
At 10:12 AM 2/25/03 -0500, you wrote:
Well, if the JVM is "crashed", how can a program or application written in Java help you manage Tomcat? That was the point.
John
> -----Original Message----- > From: Ayhan Peker [mailto:[EMAIL PROTECTED] > Sent: Tuesday, February 25, 2003 9:43 AM > To: Tomcat Users List > Subject: RE: crontab problems > > > I have no problems with tomcat... > > But sometimes under heavy load jvm 1.4 crashes... > see the links: > > Ok this is the bug: > http://developer.java.sun.com/developer/bugParade/bugs/4779653.html > unfortunately it is closed, affects 1.4.1 and will not > apparently be fixed. > It oiccurs in large apps under load.on Linux and Solaris ( > and most likely > Windows ) > It is related to / a copy of the following bug which > http://developer.java.sun.com/developer/bugParade/bugs/4724356.html > > > > > what is the best suggestion? > > just trying to determine if tomcat is running.. > if not i will restart it .. > (jvm just crashed last saturday night....I did not know > anything until the > sunday evening).. > > > At 09:29 AM 2/25/03 -0500, you wrote: > > >Yes, Tomcat is generally very stable. But: Trust, but verify. ;) > > > >John > > > > > -----Original Message----- > > > From: Hannes Schmidt [mailto:[EMAIL PROTECTED] > > > Sent: Tuesday, February 25, 2003 9:23 AM > > > To: Tomcat Users List > > > Subject: Re: crontab problems > > > > > > > > > Yes, using wget is probably the second best solution. The > > > best one is to > > > find the reason why Tomcat crashes at all, since it generally > > > is a stable > > > and reliable product. > > > > > > Cron doesn't execute more than once a minute (at least mine > > > doesn't) which > > > still is quite often. 5 or 10 minutes would be ok too. But > > > that's a matter > > > of taste, really. > > > > > > ----- Original Message ----- > > > From: "Turner, John" <[EMAIL PROTECTED]> > > > To: "'Tomcat Users List'" <[EMAIL PROTECTED]> > > > Sent: Tuesday, February 25, 2003 3:00 PM > > > Subject: RE: crontab problems > > > > > > > > > > > > > > Agreed...using a Java program to watch Tomcat seems a > > > little circular. > > > > Plus, I don't see any sort of delay or "sleep" in the > poster's JAva > > > > code...it looks like it just keeps hammering at Tomcat, as > > > the cron job is > > > > "* * * * *". Creating all those Runtime objects over and > > > over can't be > > > > helping performance any. > > > > > > > > A simple shell script using wget would be fine...sure, you > > > can watch the > > > > output of "ps -ef", but that doesn't tell you if Tomcat > is accepting > > > > requests or not. There could be an entry for Tomcat in the > > > process table, > > > > but Tomcat could be refusing requests. > > > > > > > > I just write a simple JSP page that outputs the contents of > > > a variable, > > > like > > > > "***SUCCESS***" or something like that, then use wget to > > > grab that page > > > > every so often and check for the string in the output...if > > > it's there, > > > > things should be OK (there are no guarantees). If it's > > > not, you have a > > > > problem. This way, the JSP page is compiled and cached by > > > Tomcat, it uses > > > > very little memory, and doesn't bog down the server. > > > > > > > > There are plenty of other alternatives much more robust > > > than a simple > > > shell > > > > script...you could use Netsaint/Nagios, Big Brother, and a > > > whole bunch of > > > > others. > > > > > > > > John > > > > > > > > > -----Original Message----- > > > > > From: Hannes Schmidt [mailto:[EMAIL PROTECTED] > > > > > Sent: Tuesday, February 25, 2003 6:29 AM > > > > > To: Tomcat Users List > > > > > Subject: Re: crontab problems > > > > > > > > > > > > > > > Right, you might also just put > > > > > > > > > > JAVA_HOME=... > > > > > > > > > > at the beginning of your crontab. > > > > > > > > > > I assume you have good reasons to use a Java program to > > > watch Tomcat. > > > > > Personally, I would have written a shell script. If you > > > > > really want to use > > > > > Java, you might want to use a different, more reliable > > > > > approach to detect > > > > > (un)availability of Tomcat, something like > > > > > > > > > > import java.net.*; > > > > > URL url = new URL( "http://localhost:8080/examples"; ); > > > > > URLConnection con = url.openConnection(); > > > > > con.setUseCaches( false ); > > > > > con.connect(); > > > > > if( con.getContentLength() > 0 ) { > > > > > // restart tomcat > > > > > } > > > > > > > > > > But I just wrote this out of my head ... > > > > > > > > > > ----- Original Message ----- > > > > > From: "Ralph Einfeldt" <[EMAIL PROTECTED]> > > > > > To: "Tomcat Users List" <[EMAIL PROTECTED]> > > > > > Sent: Tuesday, February 25, 2003 10:43 AM > > > > > Subject: RE: crontab problems > > > > > > > > > > > > > > > You have to make shure that your script retstart_tomcat > > > > > sets and exports all needed environment variables before > > > > > calling ./startup.sh: > > > > > > > > > > JAVA_HOME=/usr/local/java/jdk1.3.1 > > > > > CATALINA_HOME=<path to tomcat installation> > > > > > CATALINA_BASE=<path to tomcat instance> or $CATALINA_HOME > > > > > # JAVA_OPTS='-client -v' > > > > > > > > > > export JAVA_HOME CATALINA_HOME CATALINA_BASE JAVA_OPTS > > > > > ./startup.sh > > > > > > > > > > > -----Original Message----- > > > > > > From: Ayhan Peker [mailto:[EMAIL PROTECTED] > > > > > > Sent: Tuesday, February 25, 2003 10:30 AM > > > > > > To: [EMAIL PROTECTED] > > > > > > Subject: crontab problems > > > > > > > > > > > > but the last two lines returns > > > > > > ///////////////////////// > > > > > > The JAVA_HOME environment variable is not defined > > > > > > message.. > > > > > > ///////////////////////// > > > > > > my retstart_tomcat scrip is > > > > > > #!/bin/sh > > > > > > cd /usr/local/tomcat/bin > > > > > > ./startup.sh > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > > To unsubscribe, e-mail: > [EMAIL PROTECTED] > > > > > For additional commands, e-mail: > > > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > > To unsubscribe, e-mail: > [EMAIL PROTECTED] > > > > > For additional commands, e-mail: > > > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > To unsubscribe, e-mail: > [EMAIL PROTECTED] > > > > For additional commands, e-mail: > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > > For additional commands, e-mail: > [EMAIL PROTECTED] > > > > > > >--------------------------------------------------------------------- > >To unsubscribe, e-mail: [EMAIL PROTECTED] > >For additional commands, e-mail: [EMAIL PROTECTED] > >
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