Research And Application Of Crowdsourcing Task Scheduling Algorithm In Hybrid Cloud Environmen

Bag-of-tasks(Bo T)applications are generally composed of many independent tasks.These tasks don’t depend on each other,can be processed in parallel.They are usually executed in a hybrid cloud environment.The constraints of Bo T can be divided into two categories: the deadline constraint and the due date constraint.Under the deadline constraint,the application must be completed before its specified deadline,while under the due date constraint,the application is allowed to complete after the specified date,however,in this case,delay penalties are applied.In this paper,the Bo T scheduling problem in a hybrid cloud environment is studied in terms of the aforementioned constraints.Aiming at solving the Bo T scheduling problem with the deadline and the due date constraints,we propose an objective function,construct the mathematical model of the scheduling problem,and consider the maximization of the total profit of private cloud providers as the optimization goal.This work introduces a task scheduling strategy based on the efficient harmony search(EHS)algorithm to solve the Bo T scheduling problem under the deadline constraint.The algorithm optimizes the steps of generating harmony,improves the harmony fine-tuning according to the characteristics of the task sequence,and optimizes the harmony memory update,which improves greatly the efficiency of the algorithm.According to the characteristics of private cloud and public cloud,the strategy also puts forward private cloud task scheduling algorithm and public cloud task scheduling algorithm respectively.Additionally,a task scheduling strategy based on improved genetic algorithm and harmony search algorithm(IGAEHS)is proposed to solve the Bo T scheduling problem under due date constraint.The algorithm combines the improved genetic algorithm(IGA)with the EHS algorithm,and uses IGA to generate the initial harmony memory database,which enhances the directionality of the EHS and speeds up the convergence of the algorithm.The strategy also puts forward the latest start time priority algorithm and the due date task scheduling algorithm according to the characteristics of the due date task.In order to evaluate our solution,detailed simulation experiments are conducted to verify the effectiveness of the task scheduling strategy based on EHS and IGAEHS.Experimental results show that the two scheduling strategies proposed in this paper can effectively improve the total profit of private cloud providers under their constraints.Compared with the basic algorithm,it is proved that the improved scheme has a significant effect on the performance of the algorithm.Based on the above research results,we further develop a visual Bo T scheduling system,which enables the users to specify the virtual machine and to deploy a server for each application according to their needs.This helps in solving the scheduling problem of Bo T with the deadline constraints or the due date constraints,and applies the proposed EHS and IGAEHS scheduling algorithms.The scheduling results can also be displayed in the form of sequence diagram.