Hello Marijo
Welcome to the Shoal user community! :)
We are very happy to know you like Shoal and its ease of use for your
requirements.
If you are successful with deploying Shoal for the functionality you
have covered below, it would be awesome if you would give us your
success story so that it can be featured among the stories we feature in
our stories blog ? It would also be a way for some free publicity for UL
as well.
http://blogs.sun.com/stories
I have responses below for your questions:
Marijo.Cosic_at_de.ul.com wrote:
>
> Hi,
>
> first thank for the project (shoal) its really a nice peace. Currently
> i am checking the demos and reading some article's about the Apis. My
> question is regarding the clustering function of shoal.
> Is it possible to have multiple nodes in one cluster in the same VM?
I suppose your question is, can one VM participate in multiple clusters?
Sheetal (Shoal GMS Lead Developer) and Mohamed (Jxta Architect) added
support for this recently and it is being tested for the Sailfin Telco
appserver.
If your question is that multiple components within the same VM each
representing an instrument joins the same cluster then that is something
we have never tried until now. We will need to look into that use case.
>
> My problem is the following :
>
> - I want to use shoal framework to connect measurement equipment in
> the laboratory.
Would the measurement equipment talk Java? Would they embed Shoal so
they can participate in the cluster? Or would each instrument call a
dedicated Java process that represents the instrument as a proxy?
> - If a instrument goes on-line it connects to the global instrument
> cluster.
Lets call this cluster A and instance X is the instrument as a member
(core member) in this cluster. This assumes instance X has a distinct
Java process.
> - From this cluster a technician can drag and drop the node
> (instrument) into a new cluster (this time a test running with maybe
> more then 1 equipment)
Lets call this cluster B in which instrument X can now be a member (core
member) as well in addition to being a member of cluster A. In other
words, both Cluster A and B are logical groupings.
> - Therefore a runtime container, will hold maybe some instances of the
> same instrument. So now all this instruments would be a node in the
> cluster which receives information's.
Lets call this a monitoring or administrative container called M which
would like to see these instruments in the global group cluster A and in
a subset group cluster B. M would send information related to an
experiment or measurement to be performed in cluster B. For this, M
becomes a member of both the clusters as a spectator type member.
Some of the things you could benefit with Shoal that could be useful are :
1. Do you need to know when an instrument fails in either cluster? I
would imagine so. Shoal Failure Suspicion Notification and Failure
Notification can be very useful to M.
2. Do you need these instruments to tell M when they are ready to
perform operations? That would certainly be useful. The JoinedAndReady
Notification would come in handy for this purpose.
3. Suppose an instrument was performing some measurements and logging
those actions and it fails midway. Using Shoal's
FailureRecoveryNotification, M could ask another instrument to assume
ownership of those logs and complete the task that the failed instrument
was doing. That would make it a cool setup :)
4. The Planned Shutdown notification would come in handy to
administratively shutdown an instrument. Do other instruments need to
know about this ? Perhaps there is a use case for this.
>
> I hope the text above describes what i am planning and how i want to
> use shoal a the underlaying framework. In my opinion this would solve
> a lot of problems in our laboratory and would led to a
> really great infrastructure. And also it sound cool ,-) if it works.
Let us know how we can help.
If it is something production critical, we can also look into offering
commercial support from Sun at a very reasonable cost.
Do send us your feedback.
Best wishes for your project.
Shreedhar
>
> bye
>
>
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