Dynamically Reconfigurable Workflows for Time-Critical Applications

Cloud-based applications that depend on time-critical data processing or network throughput require the capability of reconfiguring their infrastructure on demand as and when conditions change. Although the ability to apply quality of service constraints on the current Cloud offering is limited, there are ongoing efforts to change this. One such effort is the European funded SWITCH project that aims to provide a programming model and toolkit to help programmers specify quality of service and quality of experience metrics of their distributed application and to provide the means to specify the reconfiguration actions which can be taken to maintain these requirements. In this paper, we present an approach to application reconfiguration by applying a workflow methodology to implement a prototype involving multiple reconfiguration scenarios of a distributed real-time social media analysis application, called Sentinel. We show that by using a lightweight RPC-based workflow approach, we can monitor a live application in real time and spawn dependency-based workflows to reconfigure the underlying Docker containers that implement the distributed components of the application. We propose to use this prototype as the basis for part of the SWITCH workbench, which will support more advanced programmable infrastructures.