Dynamic workflow support in gUSE

Scientific workflow systems aim to provide user friendly, end-to-end solutions for automating and simplifying computational or data intensive tasks. A number of workflow environments have been developed in recent years to provide support for the specification and execution of scientific workflows. Normal static workflows can poorly cope with the ever changing status of the existing distributed systems. During workflow enactment unforeseen scenarios may arise, which can cause significant delays, failed executions, or improper results. Manual workflow enactment has its obvious limitations, however automatic failover mechanisms require minimum an accurate information set about the workflow tasks and about the status of the underlying processing infrastructure. Dynamism can be defined at different abstraction levels and in different phases of the workflow lifecycle. In this paper we identify the requirements of dynamic workflows in general and provide a thorough survey about gUSE/WS-PGRADE´s dynamic workflow handling capabilities.