Gunnar Brataas

CloudScale: scalability management for cloud systems

This work-in-progress paper introduces the EU FP7 STREP CloudScale. The contribution of this paper is an overall description of CloudScales engineering approach for the design and evolution of scalable cloud applications and services. An Electronic Health Record (EHR) system serves as a motivation scenario. The overall CloudScale method describes how CloudScale will identify and gradually solve scalability problems in this existing applications. CloudScale will also enable the modelling of design alternatives and the analysis of their effect on scalability and cost. Best practices for scalability will further guide the design process. The CloudScale method is supported by three integrated tools and a scalability description modelling language. CloudScale will be validated by two case studies.

Agile Scalability Requirements

Many software organisations struggle to provide appropriate levels of scalability in their software systems. Agile development rests on pragmatic and value-centred approaches to requirement capture that allows customers and vendors to interact in the process of producing the software system that best mets the real needs of the customers. In collaboration with Norwegian software organisations we have observed that setting scalability requirements is hard. Organisations struggle because they lack a conceptually sound language for expressing scalability requirements. To improve current practice, we propose a light-weight and flexible approach to specifying scalability requirements. Flexibility ensures that a more extensive characterisation can be used if higher precision is required, and more information becomes available.

Engineering Scalable, Elastic, and Cost-Efficient Cloud Computing Applications

When building IT systems today, developers face a set of challenges unknown a few years ago. Systems have to operate in a much more dynamic world, with users coming and going in an unpredictable manner. User counts have exceeded the limit of billions of users, and the Internet of Things will even increase those numbers significantly. Hence, building scalable systems which can cope with their dynamic environment has become a major success factor for most IT service providers. Those systems are run on a vast amount of hardware and software resources offered by cloud providers. Therefore, this chapter gives an introduction into the world of cloud computing applications, the terminology and concepts used in this world, and the challenges developers face when building scalable cloud applications. Afterward, we outline our solution for engineering cloud computing applications on a very high level to give the reader a jump-start into the topic. This chapter is structured as follows. In Sect. 1.1 we sketch the world of cloud applications and motivate the need for engineering their scalability. For those who have not worked on a cloud system, we outline its characteristics in Sect. 1.2 and define its essential concepts in Sect. 1.3. As this book is about building scalable S. Becker ( ) University of Stuttgart, Universitätsstraße 38, 70569 Stuttgart, Germany e-mail: steffen.becker@informatik.uni-stuttgart.de G. Brataas SINTEF Digital, Strindvegen 4, 7034 Trondheim, Norway e-mail: gunnar.brataas@sintef.no M. Cecowski XLAB d.o.o., Pot za Brdom 100, 1000 Ljubljana, Slovenia e-mail: mariano.cecowski@xlab.si D. Huljenić • I. Stupar Ericsson Nikola Tesla, Krapinska 45, 10000 Zagreb, Croatia e-mail: darko.huljenic@ericsson.com; ivana.stupar@ericsson.com S. Lehrig IBM Research, Technology Campus, Damastown Industrial Estate, Dublin 15, Ireland e-mail: sebastian.lehrig@ibm.com

CloudStore – Towards Scalability Benchmarking in Cloud Computing

Abstract This paper describes CloudStore, an open source application that lends itself to analyzing key characteristics of Cloud computing platforms. Based on an earlier standard from transaction processing, it represents a simplified version of a typical e-commerce application – an electronic book store. We detail how a deployment on a popular public cloud offering can be instrumented to gain insight into system characteristics such as capacity, scalability, elasticity and efficiency.

CloudStore — towards scalability, elasticity, and efficiency benchmarking and analysis in Cloud computing

Abstract This paper describes CloudStore, an open source application that lends itself to analyzing key characteristics of Cloud computing platforms. Based on an earlier standard from transaction processing, it represents a simplified version of a typical e-commerce application–an electronic book store. We detail how a deployment on a popular public cloud offering can be instrumented to gain insight into system characteristics such as capacity, scalability, elasticity and efficiency. Based on our insights, we create a CloudStore performance model, allowing to accurately predict such properties already at design time.

Performance property prediction supporting variability for adaptive mobile systems

A performance property prediction (PPP) method for component-based self-adaptive applications is presented. Such performance properties are required by an adaptation middleware for reasoning about adaptation activities. Our PPP method is based on the Structure and Performance (SP) framework, a conceptually simple, yet powerful performance modelling framework based on matrices. The main contribution of this paper are the integration of SP-based PPP into a comprehensive model- and variability-based adaptation framework for context-aware mobile applications. A meta model for the SP method is described. The framework is demonstrated using a practical example.

Towards Scalability Guidelines for Semantic Data Container Management

Semantic container management is a promising approach to organize data. However, the scalability of this approach is challenging. By scalability in this paper, we mean the expressivity and size of the semantic data containers we can handle, given a suitable quality threshold. In this paper, we derive scalability characteristics of the semantic container approach in a structured way. We also describe actual experiments where we vary the number of available CPU cores and quality thresholds. We conclude this work-in-progress paper by describing how more measurements could be performed so that the missing guidelines could be provided.

Towards Agile Scalability Engineering

Scalability engineering is currently not well integrated into agile development techniques. This paper extends agile development techniques so that scalability can be handled in an incremental and iterative development process. By scalability we mean the ability of a system to handle increasing workload. We propose the ScrumScale Method which includes scalability engineering in Scrum. This extension should also be applicable to other agile techniques. For scalability testing, we indicate how quality thresholds should be scaled up or down according to the degree of completeness of the product, test hardware, test software, test data and test workload. Using action research, we have conducted three pilots in three Norwegian software organizations. These three pilots have different architectures and operate in different markets yet have in common scalability challenges.

The CloudScale Method.

This chapter details the CloudScale method. We describe its high-level process with the most important steps. We look more closely at the CloudScale method from Sect. 2.1 and detail it with respect to the developer roles executing it. We also introduce the two major method use cases. Method use case I is about analyzing a modeled system; method use case II deals with analyzing and migrating an implemented system. All discussions in this chapter are guided by the granularity of the analysis you want to perform, hence; this chapter also introduces granularity as a key concept and discusses how to find the right one.

CloudScale Method Quick View

In this chapter, we overview the complete CloudScale method and show how the CloudScale method relates to existing development processes. Our overview is accompanied by a running example termed CloudStore—a simple online bookshop to be operated in a cloud computing environment. In a fictional scenario, we exemplify how a software architect follows the CloudScale method to realize CloudStore. The architect finally realizes CloudStore such that all of its scalability, elasticity, and cost-efficiency requirements are fulfilled. After having exemplified the CloudScale method, additional guidelines for software architects are given in the form of best practices (HowTos) and common pitfalls (HowNotTos). The chapter closes with a discussion on how the CloudScale method can be integrated into existing development processes such as the Unified Process.