kjkoster
05-01-2009, 22:09
http://java-monitor.com/postedimages/dbac2815-84a8-4dd7-baa0-bcad355269ff.png
Dear All,
Well, aint I the lucky one. Here is a graph from one of my machines that shows what it looks like when the probe keeps reconnecting.
As I logged into the machine I noticed that setting up ssh connections to the machine were really slow. From experience I know that this sometimes happens when the DNS names do not resolve properly.
Here is what I found in the Tomcat logs:
Jan 5, 2009 9:58:46 PM com.javamonitor.CollectorServlet$CollectorDriver run
SEVERE: This probe was hit by an unexpected exception (it will retry in fifteen minutes): foo.example.com: foo.example.com
java.net.UnknownHostException: foo.example.com: foo.example.com
at java.net.InetAddress.getLocalHost(InetAddress.java :1353)
at com.javamonitor.Collector.push(Collector.java:59)
at com.javamonitor.CollectorServlet$CollectorDriver.r un(CollectorServlet.java:74)
at java.lang.Thread.run(Thread.java:619)
Using dig(1) (http://www.freebsd.org/cgi/man.cgi?query=dig), I get the message connection timed out; no servers could be reached for about half the queries. The other half take more than 5 seconds to respond.
So there you have it: DNS lookup problems.
The graph above is typical for probes that fail to connect to the Java-monitor collector service for some reason. As you can on the right, a graph that is usually a solid block turns semi-transparent.
Now, if only that was my own DNS server, then I would not have to sit here, biting my nails until this is fixed. :-/
Kees Jan
Dear All,
Well, aint I the lucky one. Here is a graph from one of my machines that shows what it looks like when the probe keeps reconnecting.
As I logged into the machine I noticed that setting up ssh connections to the machine were really slow. From experience I know that this sometimes happens when the DNS names do not resolve properly.
Here is what I found in the Tomcat logs:
Jan 5, 2009 9:58:46 PM com.javamonitor.CollectorServlet$CollectorDriver run
SEVERE: This probe was hit by an unexpected exception (it will retry in fifteen minutes): foo.example.com: foo.example.com
java.net.UnknownHostException: foo.example.com: foo.example.com
at java.net.InetAddress.getLocalHost(InetAddress.java :1353)
at com.javamonitor.Collector.push(Collector.java:59)
at com.javamonitor.CollectorServlet$CollectorDriver.r un(CollectorServlet.java:74)
at java.lang.Thread.run(Thread.java:619)
Using dig(1) (http://www.freebsd.org/cgi/man.cgi?query=dig), I get the message connection timed out; no servers could be reached for about half the queries. The other half take more than 5 seconds to respond.
So there you have it: DNS lookup problems.
The graph above is typical for probes that fail to connect to the Java-monitor collector service for some reason. As you can on the right, a graph that is usually a solid block turns semi-transparent.
Now, if only that was my own DNS server, then I would not have to sit here, biting my nails until this is fixed. :-/
Kees Jan