Re: Clustering and load balancing behavior for services hosted on Tuscany Runtime.

[Simon Laws <si...@googlemail.com>]

Hi Sandesh

Some thoughts inline,

> So my questions are -
> 1) Can we host tuscany in any Appserver?
> site documentation says that it can be done but please point me to the
> document
> that explains how to achieve this.

It's a bit spread around as the people with accesss to specific
platforms have tended to blog about how to do it. See the links from
this page (http://tuscany.apache.org/sca-java-user-guide.html)


> 2) Assuming it is possible to host tuscany in Appserver say weblogic, then
> can
> I host same services (same SCA application) in 2 different nodes of a
> cluster, so that
> same service is available on both the tuscany nodes hosted on respective
> appserver
> nodes. And even if one appserver node crashes, tuscany services are
> available to
> serve the request by external clients or by EAR application in other node?

You would have to run the same composite on the two nodes. We tried
this in 1.x with a load balancing demo where we have Tuscany running
in multiple Tomcat instances being driven by Apahce HTTPD with a
balancer plugin. I couldn't work out how to make all this run as part
of our maven build so it didn't make it into the build proper.

> 3) If such a clustering behavior is supported, then for a two node cluster,
> is load-balancing done using round-robbin or some other algorithm?

Supported is a probably a bit strong at the moment. You can make it
work but we don't test for it. There is no built in load balancing
function in Tuscany so it relies on whatever load balancing features
are provided by the app server.

> 4) How to dynamically deploy SCA applications to a already running Tuscany
> node/domain?

In 1.x we are not very good at dynamic deployment. You can start up
new nodes any time you like. This is fine when the composites that
refer to them are not already started. Running composites can't be
updated.

Regards

Simon