The nr-of-instances parameter seems confusing to me when used with cluster aware routers. In the example in the documentation (http://doc.akka.io/docs/akka/snapshot/scala/cluster-usage.html) the parameter is set to 100 so that "new routees (are) added to the router" and the real number of routees can be any value between 0 and 100?. This behavior is different from normal routers, where 100 routees would be created. When I omit nr-of-instances, only one routee is added, further joining cluster members seem to be ignored. The default value for nr-of-instances which I did not find in the documentation seems to be 1?

What I suggest:
a) Introduce parameter max-nr-of-instances and make it mandatory for cluster aware routers.
or
b) Change the default of nr-of-instances from (1)? to "no limit". Remove the parameter from the examples.
and
Adjust the documentation.