The GSN Controller is an intelligent component that manages real time data distribution and performs optimization techniques on virtualized GSN resources. The overall objective of GSN Controller is to maximize utilization of sun- & wind-powered facilities. Its performance can be measured in terms of "intermittent power utilization”. Its role consists on:
The overall architecture of GSN Controller is shown in the following figure.
The Controller is the brain of the network, which is responsible for determining the optimal location of each VM. It computes the action plans to be executed on resources, and then orders the managers to perform them. Based on information provided by the Controller, the managers execute relocation and migration tasks. The relationship between the Controller and managers can be regarded as the Controller/Forwarder connection in an IP router. The Controller keeps an overall view of the entire network; it computes the best location for each VM and updates a Resource Location Table (RLT). A “snapshot” of the RLT is recorded to the managers. When there is a request for the creation of a new VM, a manager will look up the table to determine the best location of the new VM. If there is a change in the network, e.g., when the power source of a data center dwindles, the controller re-computes best locations for VMs and updates the managers with the new RLT.
An illustration on how the GSN Controller (SCL: Simple Controller Logic implementation) which implements ''Follow the sun/ Follow the wind'' scenario is shown below.