Startup AND shutdown of separate JVM's

[Scott Tatum <sc...@wcom.com>]

I have been using Tomcat for a while now and with good success. I
recently setup virtual hosts (named vhosts) and was surprised when it
all worked the first time. =) The documentation in the mod_jk-howto was
a great help.

Here is my setup: I have two different (eventually more) virtual hosts
on one machine being served by Tomcat 3.2.1 and Apache 1.3.14. Right now
there is only one Tomcat JVM running, but I'm getting ready to break
this up into 2 separate JVM's. The configuration part is trivial now
that I have virtual hosts working, but there is one part I can't figure
out.

The two vhost setup is for production and development versions of the
same application. So one JVM I will need to restart regularly, and the
other needs to stay up as much as possible.

There are a couple of problems I forsee that I need to understand and
tackle before moving forward. One is that there is only startup/shutdown
script for Tomcat. I understand that, by creating different server.xml
configuration files and using (e.g.) startup.sh -f server1.xml, I can
start separate servers. My question is, how do I stop them separately?
If I have to write my own scripts I am willing to go that route, I just
want to make sure there's not some preexisting method.

Also I read in the FAQ that if you restart Tomcat, you also have to
restart Apache. I've tested this out with mixed results. Is this true?
If that is the case, running separate JVM's for each website becomes
useless to me. No offense to the other benefits of running separate
JVM's! If I have my production JVM which needs to stay up, but Apache
has to restart every time I restart my development JVM, wouldn't that
mean I have to restart my production JVM every time I restart my
development JVM? Worst case, I can run my development on the built-in
webserver, but it would be nice to use app.domain.com and
app-dev.domain.com without having to tack on a :8080.

So in review, my questions are: If running separate JVM's connected to a
single Apache, how do I restart one JVM while leaving the other running?
Also, if running under said setup, does restarting one Tomcat JVM mean
that Apache and any other Tomcat JVM's have to be restarted as well?
Thanks in advance for any insight.

-Scott
(p.s. was running JRun 3 before Tomcat. Experienced daily lockups. No
lockups with Tomcat and it is noticeably faster. JRun 3 has a nice
web-based admin setup though.)
--
Scott Tatum | scott.tatum@wcom.com
Senior Applications Developer, Special Projects
WorldCom | http://www.wcom.com/

Re: Startup AND shutdown of separate JVM's

[Milt Epstein <me...@uiuc.edu>]

On Thu, 1 Mar 2001, Scott Tatum wrote:

[ ... ]
> So in review, my questions are: If running separate JVM's connected
> to a single Apache, how do I restart one JVM while leaving the other
> running?  Also, if running under said setup, does restarting one
> Tomcat JVM mean that Apache and any other Tomcat JVM's have to be
> restarted as well?  Thanks in advance for any insight.

As to your first question, check out:

http://jakarta.apache.org/tomcat/jakarta-tomcat/src/doc/uguide/tomcat_ug.html

particularly the section "Configuring for Multiple Tomcat JVMs".  If I
understand correctly what you are trying to do, it seems to talk about
just what you're looking for (in particular, the startup.sh script can
take an option that specifies the server.xml file).

Hmmm, in re-reading the part of your note that I deleted, I see that
you're already aware of that, and you're worried about shutdown.
Well, that's not explicitly covered in the above document, but perhaps
the shutdown.sh script can take that same option.  I do note that the
tomcat.sh script, which both startup.sh and shutdown.sh call, passes
any incoming command line options/arguments to the java class it runs,
for both start and stop (and those two scripts pass their command line
options/arguments to tomcat.sh).

As to your second question, I myself am confused as to when Apache and
Tomcat need to be restarted as well (although my questions have more
to do with what needs to be done so that changes in certain config
files are picked up), and perhaps someone can comment on that.

Milt Epstein
Research Programmer
Software/Systems Development Group
Computing and Communications Services Office (CCSO)
University of Illinois at Urbana-Champaign (UIUC)
mepstein@uiuc.edu