Proactive Prediction Models for Web Application Resource Provisioning in the Cloud _______________________________ Samuel A. Ajila & Bankole A. Akindele

Presentation Outline  Introduction to Problem Area  Motivation  Goals and Scope  Contributions  Related work  Machine learning algorithms  Implementation setup  Evaluation metrics  Selected results  Conclusion 2

Introduction  Cloud computing refers to both the applications delivered as services over the Internet and the hardware and systems software in the data centers that provide those services (SaaS, PaaS and IaaS)  Challenges include: Data security threats, performance unpredictability and prompt (quick) resource scaling  Accurate Virtual machine (VM) resource provisioning: under and over-provisioning  Current techniques like Control theory, Constraint programming and Machine learning 3

Motivation  VM instantiation (scaling) takes time and ranges from 5 to 12 minutes  Challenges that can result from the instantiation duration: Possibility of Service Level Agreement (SLA) violations - Cloud providers Poor customer’s Quality of Experience (QoE) – Cloud client Reputation loss – Cloud client/providers  Presently, monitoring metrics made available to clients are limited to CPU, Memory and Network utilization  The motivation is to “predict resource usage so that cloud providers can make adequate provisioning ahead of time”  To extend the monitoring metrics by including Response time and Throughput 4

Goals and Scope  Design and develop a cloud client prediction model for cloud resource provisioning in a Multitier web application environment  The model would be capable of forecasting future resource usage to enable timely VM provisioning  To achieve this goal, SVM, NN and LR learning techniques are analysed using the Java implementation of TPC-W (workload)  The scope of this work is limited to IaaS  Prediction model is built around the web server tier. It is possible to extend to other tiers 5

Contributions  Design and development of a cloud client prediction model that uses historical data to forecast future resource usage  The evaluation of the resource usage prediction capability of SVM, NN and LR using three benchmark workloads from TPC-W  The extension of the prediction model to include Throughput and Response time, thus providing wider and better scaling decision options for cloud clients  The comparison of the prediction capability of SVM, NN and LR models under random and steady traffic patterns 6

Related works Table 1: Auto-scaling techniques 7 TechniqueClassComments Threshold/Rule based ReactiveReacts to system changes but do not anticipate them Control theoryReactive/ProactiveExcept where used with a proactive approach it suffers reactive issues Queuing theoryReactiveAs complexity of system grows, the analytic formulas become difficult Reinforcement learning Reactive/ProactiveGood but converging at optimal policy can be unfeasibly long (state –action pairs) Time series analysisProactiveGood and promising

Machine learning algorithms 8

Machine learning algorithms (cont’d) 9 Figure 1 : Single hidden layer, feed forward neural network

Machine learning algorithms (cont’d) 10

Architecture 11 Figure 2 Implementation architecture

Implementation setup (cont’d) Time (minutes) Shopping mix users Browsing mix users Ordering mix users Total user Requests  Total length of experiment was about 10 hours  Selected experimental workload mix

Evaluation metrics 13  Evaluation is done on the 60% training and 40% held out test dataset  The held out dataset is used to forecast to a maximum interval of 12 minutes (VM instantiation time reported by other authors)

CPU Training & Testing Performance 14

Selected results (cont’d) 15 CPU utilization test performance metric ModelMAPERMSEMAEPRED(25) LR NN SVR Figure 5 CPU Utilization Actual and Predicted test model results

Selected results (cont’d) 16 Throughput test performance metric ModelMAPERMSEMAEPRED(25) LR NN SVR Figure 6 Throughput Actual and Predicted test model results

Selected results (cont’d) 17 Response time test performance metric ModelMAPERMSEMAEPRED(25) LR NN SVR Figure 7 Response time Actual and Predicted test model results

CPU - Comparison of Prediction Models 18

Throughput – Comparison of Prediction Models 19

Sensitivity Measurement Using Little’s Law 20

Conclusion  SVR displayed superior prediction accuracy over both LR and NN in a typically nonlinear, not defined a-priori workload by:  In the CPU utilization prediction model, SVR outperformed LR and NN by 58% and 120% respectively  For the Throughput prediction model, SVR again outperformed LR and NN by 12% and 76% respectively; and finally,  The Response time prediction model saw SVR outperforming LR and NN by 26% and 80% respectively.  Based on this experimental results SVR may be accepted as the best prediction model in a nonlinear, not defined a-priori system 21

Future works  SVR and other machine learning algorithms are good for forecasting, however training and retraining is a challenge Parameter selection is still empirical  Combination of SVR and other predicting techniques may mitigate this challenge  Other future direction include Inclusion of database tier for a more robust scaling decision Resource prediction on other non-web application workload 22

Questions 23 Thank You