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From Jules Gosnell <>
Subject Re: [wadi-dev] Clustering: WADI/Geronimo integrations.
Date Thu, 12 Jan 2006 12:40:13 GMT
Here is a list of outstanding issues associated with this work:

- ActiveMQ's shutdown hook seems to trigger when Geronimo is shutdown, 
removing AMQ before WADI - WADI doesn't like this. I have added a 
property to the script which suppresses this behaviour. I will 
document it in the Getting Started doc.

- There 'may' be issues with nodes finding each other, when a Geronimo 
node is introduced into a WADI cluster - investigating.

- Jeff - you should look over the changes and make sure that they do not 
impact on any other TC fn-ality. They were done with Emacs, so the 
formatting may be offensive. Please feel free to make them your own and 
bring any issues back to the list. The WADIGBean, is no longer used, so 
you may want to remove this from the repo.

- Jan and Jeff - since this config is now done on the container bean and 
not in the geronimo-web.xml, you may no longer need to implement your 
own geronimo-web.xml schemas (I haven't looked very closely at TC). You 
may want to consider this and perhaps lose them.

- In order to get the same webapp to work in all containers 
(tomcat5[05], jetty[56], geronimo-[tomcat/jetty], jboss-tomcat), I had 
to move deps back to Geronimo container-level. These include Axion, 
which I know will upset Jeff. As I have stated before, WADI's dependence 
on Axion is easily removed. If Jeff or anyone wants to look at replacing 
it with Derby, it is fine with me, as long as they do some testing and 
confirm that having created a session on a single node and restarted it, 
the session survives (if the DB is still running). This needs to be 
tested on all supported containers. Axion was used because it is an 
in-VM DB (so imposes no further integration dependencies on the Getting 
Started stuff and is useful for unit-testing) and was in use by Geronimo 
at the time. So I suggest that any replacement needs to also be able to 
run in-vm aswell. As we go further and move WADI's actual configuration 
from the app to the container-level, these issues will disappear and 
WADI will be able to be hooked to whatever persistance mechanism is 
shipped in Geronimo by default.

- Jan & Jeff , you may want to consider pushing some of this session 
manager selection code up into a shared GeronimoWebContainer abstraction 
so that you don't both end up maintaining similar but diverging code...

- I may have overlooked a couple of issues. If I come across them, I 
shall post them.

Further work on Geronimo integration :

- more testing
- make a new WADI release and update geronimo-trunk to use it
- look at applying diffs to a G1.0 tree and producing a binary patch for 
1.0 distros.
- update website and release it


Jules Gosnell wrote:

> Guys,
> Jan and I have just refactored the Geronimo Jetty and Tomcat 
> integrations to take the same approach to the installation of a 3rd 
> party session manager, to ease the integration of WADI. This is now 
> checked in on Geronimo's trunk.
> Each top level web container GBean now supports a pair of attributes - 
> LocalSessionManager and DistributableSessionManager. These may be used 
> to override the container's choice of SessionManager for webapps with 
> and without the <distributable/> tag present in the WEB-INF/web.xml, 
> respectively.
> The attributes expect to be given a classname, if required, this class 
> will be loaded and instantiated. The resulting instance will be used 
> as the session manager. If not provided, the container will use a 
> sensible default. Currently Jetty and TC are set up to use their own 
> default session managers in the local case and the correct WADI 
> session manager in the distributable case.
> This means that the same WADI-enabled webapp, with its plan held 
> internally (WEB-INF/geronimo-web.xml) may now be hot-deployed on 
> either a Jetty or a Tomcat based Geronimo, without changes :-)
> I will post specific WADI issues to the WADI dev lists 
> (,
> This shouldn't be seen as a final position on the subject - there is 
> still much to talk about, but is a useful interim step, that allows us 
> to have something working whilst we figure out how to go forward.
> Enjoy,
> Jules

"Open Source is a self-assembling organism. You dangle a piece of
string into a super-saturated solution and a whole operating-system
crystallises out around it."

 * Jules Gosnell
 * Partner
 * Core Developers Network (Europe)
 * Open Source Training & Support.

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