171,317 research outputs found

    Optimised auto-scaling for cloud-based web service

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    University of Technology Sydney. Faculty of Engineering and Information Technology.Elasticity and cost-effectiveness are two key features for ensuring that cloud-based web services appeal to more businesses. However, true elasticity and cost-effectiveness in the pay-per-use cloud business model has not yet been fully achieved. The explosion of cloud-based web services brings new challenges to enable the automatic scaling up and down of service provision when the workload is time-varying. This research studies the problems associated with these challenges. It proposes a novel scheme to achieve optimised auto-scaling for cloud-based web services from three levels of cloud structure: Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). At the various levels, auto-scaling for cloud-based web services has different problems and requires different solutions. At the SaaS level, this study investigates how to design and develop scalable web services, especially for time-consuming applications. To achieve the greatest efficiency, the optimisation of service provision problem is studied by providing the minimum functionality and fastest scalability performance concerning the speed-up curve and QoS (Quality of Service) of the SLA (Service-Level Agreement). At the PaaS level, this work studies how to support dynamic re-configuration when workloads change and the effective deployment of various kinds of web services to the cloud. To achieve optimised auto-scaling of this deployment, a platform is designed to deploy all web services automatically with the minimal number of cloud resources by satisfying the QoS of SLAs. At the IaaS level for two infrastructure resources of virtual machine (VM) and virtual network (VN), this research focuses on studying two types of cloud-based web service: computation-intensive and bandwidth-intensive. To address the optimised auto-scaling problem for computation-intensive cloud-based web service, data-driven VM auto-scaling approaches are proposed to handle the workload in both stable and dynamic environments. To address the optimised auto-scaling problem for bandwidth-intensive cloud-based web service, this study proposes a novel approach to predict the volume of requests and dynamically adjust the software defined network (SDN)-based network configuration in the cloud to auto-scale the service with minimal cost. This research proposes comprehensive and profound perspectives to solve the auto-scaling optimisation problems for cloud-based web services. The proposed approaches not only enable cloud-based web services to minimise resource consumption while auto-scaling service provision to achieve satisfying performance, but also save energy consumption for the global realisation of green computing. The performance of the proposed approaches has been evaluated on a public platform (e.g. Amazon EC2) with the real dataset workload of web services. The experiment results demonstrate that the proposed approaches are practicable and achieve superior performance to other benchmark methods

    Blockchain-Enabled DPKI Framework

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    Public Key Infrastructures (PKIs), which rely on digital signature technology and establishment of trust and security association parameters between entities, allow entities to interoperate with authentication proofs, using standardized digital certificates (with X.509v3 as the current reference). Despite PKI technology being used by many applications for their security foundations (e.g. WEB/HTTPS/TLS, Cloud-Enabled Services, LANs/WLANs Security, VPNs, IP-Security), there are several concerns regarding their inherent design assumptions based on a centralized trust model. To avoid some problems and drawbacks that emerged from the centralization assumptions, a Decentralized Public Key Infrastructure (DPKI), is an alternative approach. The main idea for DPKIs is the ability to establish trust relations between all parties, in a web-of-trust model, avoiding centralized authorities and related root-of-trust certificates. As a possible solution for DPKI frameworks, the Blockchain technology, as an enabler solution, can help overcome some of the identified PKI problems and security drawbacks. Blockchain-enabled DPKIs can be designed to address a fully decentralized ledger for managed certificates, providing data-replication with strong consistency guarantees, and fairly distributed trust management properties founded on a P2P trust model. In this approach, typical PKI functions are supported cooperatively, with validity agreement based on consistency criteria, for issuing, verification and revocation of X509v3 certificates. It is also possible to address mechanisms to provide rapid reaction of principals in the verification of traceable, shared and immutable history logs of state-changes related to the life-cycle of certificates, with certificate validation rules established consistently by programmable Smart Contracts executed by peers. In this dissertation we designed, implemented and evaluated a Blockchain-Enabled Decentralized Public Key Infrastructure (DPKI) framework, providing an implementation prototype solution that can be used and to support experimental research. The proposal is based on a framework instantiating a permissioned collaborative consortium model, using the service planes supported in an extended Blockchain platform leveraged by the Hyperledger Fabric (HLF) solution. In our proposed DPKI framework model, X509v3 certificates are issued and managed following security invariants, processing rules, managing trust assumptions and establishing consistency metrics, defined and executed in a decentralized way by the Blockchain nodes, using Smart Contracts. Certificates are issued cooperatively and can be issued with group-oriented threshold-based Byzantine fault-tolerant (BFT) signatures, as group-oriented authentication proofs. The Smart Contracts dictate how Blockchain peers participate consistently in issuing, signing, attestation, validation and revocation processes. Any peer can validate certificates obtaining their consistent states consolidated in closed blocks in a Meckle tree structure maintained in the Blockchain. State-transition operations are managed with serializability guarantees, provided by Byzantine Fault Tolerant (BFT) consensus primitives

    Technical Report on Deploying a highly secured OpenStack Cloud Infrastructure using BradStack as a Case Study

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    Cloud computing has emerged as a popular paradigm and an attractive model for providing a reliable distributed computing model.it is increasing attracting huge attention both in academic research and industrial initiatives. Cloud deployments are paramount for institution and organizations of all scales. The availability of a flexible, free open source cloud platform designed with no propriety software and the ability of its integration with legacy systems and third-party applications are fundamental. Open stack is a free and opensource software released under the terms of Apache license with a fragmented and distributed architecture making it highly flexible. This project was initiated and aimed at designing a secured cloud infrastructure called BradStack, which is built on OpenStack in the Computing Laboratory at the University of Bradford. In this report, we present and discuss the steps required in deploying a secured BradStack Multi-node cloud infrastructure and conducting Penetration testing on OpenStack Services to validate the effectiveness of the security controls on the BradStack platform. This report serves as a practical guideline, focusing on security and practical infrastructure related issues. It also serves as a reference for institutions looking at the possibilities of implementing a secured cloud solution.Comment: 38 pages, 19 figures

    High-Performance Cloud Computing: A View of Scientific Applications

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    Scientific computing often requires the availability of a massive number of computers for performing large scale experiments. Traditionally, these needs have been addressed by using high-performance computing solutions and installed facilities such as clusters and super computers, which are difficult to setup, maintain, and operate. Cloud computing provides scientists with a completely new model of utilizing the computing infrastructure. Compute resources, storage resources, as well as applications, can be dynamically provisioned (and integrated within the existing infrastructure) on a pay per use basis. These resources can be released when they are no more needed. Such services are often offered within the context of a Service Level Agreement (SLA), which ensure the desired Quality of Service (QoS). Aneka, an enterprise Cloud computing solution, harnesses the power of compute resources by relying on private and public Clouds and delivers to users the desired QoS. Its flexible and service based infrastructure supports multiple programming paradigms that make Aneka address a variety of different scenarios: from finance applications to computational science. As examples of scientific computing in the Cloud, we present a preliminary case study on using Aneka for the classification of gene expression data and the execution of fMRI brain imaging workflow.Comment: 13 pages, 9 figures, conference pape

    Cloudbus Toolkit for Market-Oriented Cloud Computing

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    This keynote paper: (1) presents the 21st century vision of computing and identifies various IT paradigms promising to deliver computing as a utility; (2) defines the architecture for creating market-oriented Clouds and computing atmosphere by leveraging technologies such as virtual machines; (3) provides thoughts on market-based resource management strategies that encompass both customer-driven service management and computational risk management to sustain SLA-oriented resource allocation; (4) presents the work carried out as part of our new Cloud Computing initiative, called Cloudbus: (i) Aneka, a Platform as a Service software system containing SDK (Software Development Kit) for construction of Cloud applications and deployment on private or public Clouds, in addition to supporting market-oriented resource management; (ii) internetworking of Clouds for dynamic creation of federated computing environments for scaling of elastic applications; (iii) creation of 3rd party Cloud brokering services for building content delivery networks and e-Science applications and their deployment on capabilities of IaaS providers such as Amazon along with Grid mashups; (iv) CloudSim supporting modelling and simulation of Clouds for performance studies; (v) Energy Efficient Resource Allocation Mechanisms and Techniques for creation and management of Green Clouds; and (vi) pathways for future research.Comment: 21 pages, 6 figures, 2 tables, Conference pape
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