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From Hannes Schmidt <m...@schmidt-net.via.t-online.de>
Subject Re: crontab problems
Date Tue, 25 Feb 2003 14:22:36 GMT
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" <JTurner@AAS.com>
To: "'Tomcat Users List'" <tomcat-user@jakarta.apache.org>
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:mail@schmidt-net.via.t-online.de]
> > 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" <ralph.einfeldt@uptime-isc.de>
> > To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
> > 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:ayhan@image-data.com]
> > > Sent: Tuesday, February 25, 2003 10:30 AM
> > > To: tomcat-user@jakarta.apache.org
> > > 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
> >
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> >
> >
> >
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> >
>
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>


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