A Declarative Optimization Engine for Resource Provisioning of Scientific Workflows in Geo-Distributed Clouds

Geo-distributed clouds are becoming increasingly popular for cloud providers, and data centers with different regions often offer different prices, even for the same type of virtual machines. Resource provisioning in geo-distributed clouds is an important and complicated problem for budget and performance optimizations of scientific workflows. Scientists are facing the complexities resulted from various cloud offerings in the geo-distributed settings, severe cloud performance dynamics and evolving user requirements on performance and cost. To address those complexities, we propose a declarative optimization engine named Geco for resource provisioning of scientific workflows in geo-distributed clouds. Geco allows users to specify their workflow optimization goals and constraints of specific problems with an extended declarative language. We propose a novel probabilistic optimization approach for evaluating the declarative optimization goals and constraints to address the cloud dynamics. Additionally, we develop runtime optimizations to more effectively utilize the cloud resources at runtime. To accelerate the solution finding, Geco leverages the power of GPUs to find the solution in a fast and timely manner. Our evaluations with four common workflow provisioning problems demonstrate that, Geco is able to achieve more effective performance/cost optimizations in geo-distributed cloud environments than the state-of-the-art approaches.