Feature Description:

NIN: number of microservice instances residing in the current node
Scope: Invocation
Detail description:
    NIN is the number of microservice instances residing in the current node. Microservice instances can reside in the same or
different node. For example, microservice instances A1, B2 and C2 reside in node N1 and microservice instances A2 and B1 reside
in node N2, so the NIN of node N1 is 3 and the NIN of node N2 is 2.