[Wrapper-user] clustering and java service wrapper

[jeroen v. <jvr...@gm...>]

Hi everybody,



This is my first time for posting a question here, but I thought it would
be best to ask some help with people who are familiar with the java service
wrapper already.



So maybe it’s best that I give you some information about why I’m asking
this question and why I need your help.

So I’m a student from Belgium, and I’m currently doing my thesis(graduation
paper?).



The company were I’m doing this asked me to revise and migrate an existing
servercluster infrastructure. I’ve been working the past 2 weeks on
checking out the possibilities to upgrade and improve the existing
structure,

And I think I have given them some options on that side.



Now I have come to the actual clustering. The servercluster is only used to
cluster java-applications and services.

There are a number of generic applications that run on the cluster, which
are using the java service wrapper.



Now; one of the problems that they are having, is that when an
administrator logs on to one of the servernodes, and logs off again, all
the generic applications restart.

They were thinking that this problem was probably caused by the wrapper.



After reading the documentation, I seem to have found some indications that
indeed point in this direction.

Not saying that the wrapper itself is doing anything wrong, but I think
that it’s probably used in a wrong manner.



*“The problem is that Java on its own can not be run as a service. Many
simple tools like the Windows "sc" command can be used to run Java as a
service, but the user doing something as simple as logging off of the
machine will cause Java to shutdown.“*

* *

*“Most Java applications die rather abruptly if the user presses CTRL-C,
logs out of Windows, etc. You can work around some of these issues with a
Shutdown Hook, but the Wrapper implements this by using a **native
library<http://wrapper.tanukisoftware.com/doc/english/prop-native-library.html>
** to directly capture the system signals. This makes it possible to have a
Java application installed as a Windows Service without it being stopped
when a user logs out. “*

* *

* *

Now, what I think is what happens: the generic applications aren’t
correctly set-up to run as a windows service(probably combination of
clustering resource and java service wrapper misconfiguration),

which causes the JVM’s to stop when logging off. The cluster notices that
there is something wrong with the clustering resource(generic application),
and starts it back up.

This caused them to think at the company that the resources restarted, but
I think this isn’t the case. It’s the JVM that stops, and the clustering
that steps in.



Now, I’m wondering where I need to start looking to fix this problem. I
think the problem lies with the fact that the java-application isn’t
running as a windows service.

I did already notice something with the command line parameters of the
generic resources. They are using the following commands to run the java
applications:

X:\Foo\Bar\FooBAR\bin\wrapper.exe -c  X:\ Foo \ Bar \ FooBAR
\conf\wrapper.conf



If my first quick read of the documentation was correctly, that will let it
run as a console-application. Don’t know if this has anything to do with
it, just guessing.

I’m probably going to re-read the whole documentation again, to get myself
more familiar with the java service wrapper.

I’m not just looking for the answer, I really want to look into the problem
here. That’s why I’m looking for some input here, to get a point to work
from.

My time is limited, so I need to work efficient(need to do management and
probably a whole lot of testing), so I thought it would be best to ask for
some help here.



So is there someone who has some experience with clustering and java
service wrapper?  Or somebody that has a hunch what the problem is?



Your help will certainly be appreciated.

I apologize for my bad English, and hoping to hear your ideas on this one.



Vranckx Jeroen