Conclusion notes if it can help someone else:
- At first I did not see the "shared subscription" option in the ibm iot node config (It is actually called "scalable").
- BUT : to enable it on an IBM iot IN node, you can not use the "bluemix service" option. You need to set "API key" and this allows you to define a node config. You just need to enter the API key and token that are in the VCAP services, and then tick "scalable"
I just put a random number in the APP ID.
Works, now the mqtt messages are not dupplicated but load balanced between my instances. .
