Notes on Cloud computing principles

This letter provides a review of fundamental distributed systems and economic Cloud computing principles. These principles are frequently deployed in their respective fields, but their inter-dependencies are often neglected. Given that Cloud Computing first and foremost is a new business model, a new model to sell computational resources, the understanding of these concepts is facilitated by treating them in unison. Here, we review some of the most important concepts and how they relate to each other

State-preserving container orchestration in failover scenarios

Containers have been widely adopted for deployment of high availability applications and services. This adoption is in part due to the native support of fault tolerance mechanisms in container orchestration frameworks such as Kubernetes. While Kubernetes provides service replication as a fault tolerance mechanism for stateless applications, service replication does not satisfy requirements for stateful applications. Currently this shortcoming is addressed by data replication in databases. This requires a tight coupling and modification of the stateful application to support high availability. Thus, this thesis proposes a new Checkpoint/Restore (C/R) Kubernetes operator to achieve fault tolerance for stateful applications without any modification of the application. The operator takes a checkpoint in a configurable interval. In case of a fault a new application container is created automatically from the most recent checkpoint. We compare the proposed approach with a more conventional approach in which we pull and restore the application state from the application through an API. We measure the overhead of both methods, the service interruption and the recovery time in case of faults. We find the C/R Operator has similar performance in recovery time as the traditional approach, but does not need any application modification. The results signify C/R as a promising technology for a fault tolerance mechanism for stateful applications

Performance Implications For the Use of Virtual Machines Versus Shielded Virtual Machines in High-Availability Virtualized Infrastructures

Use of virtualization in datacenter or service providers or even in cloud computing environments brings many benefits. Virtualization, whether it is for services, applications or servers, is no longer a trend to be a reality in many industries and areas, whether in or outside the technology area. Therefore, with this emergent use of virtualization companies have been asking a lot about the performance and security of using virtual machines in a highly availability infrastructures. Controlling the access to Virtual Machines is a security issues that all the hypervisors haves, such as, VMware vSphere, Hyper-V or KVM. To make virtual machines more secure Microsoft has introduced the concept of Shielded virtual machines. Taking this into account, this dissertation presents a study on key concepts behind virtual machines, Guarded Fabric, Host Guardian Service, Guarded Hosts and shielded virtual machines. A Shielded VM is a Generation 2 feature (supported on Windows Server 2012 and later) that comes with a virtual Trusted Platform Module (TPM), which can only run on healthy and approved hosts in the fabric and is encrypted using BitLocker. In order to support our study an experimental bed test has been setup, involving a failover cluster with native virtualization at the hardware level with Windows Server 2016 Hyper-V. In the test environment, a failover clustering, FreeNAS Storage, ISCSI Target, VMs, Guarded Fabric and Shielded virtual machines have been implemented and configured. After the implementation of the bed test, a set of tests and experiments haves been made in order to study the performance implications for the use of virtual machines versus shielded virtual machine in High Availability Virtualized Infrastructures. Finally, an analysis at the results worked through the tests has been made, according to the Background made in the first part and the bed test deployed. A set of experiments has been made in virtual machines and shielded virtual machines in order to evaluate its performance in terms of CPU, RAM and writing speed. The results show that the use of shielded virtual machines leads to a small degradation of performance compared to the use of regular virtual machines, but, on the other hand, it has also been shown that the shielded virtual machines allows to restrict access to the virtual machines only for run on trusted hosts, and prevent unauthorized administrators and malwares from compromising the virtual machine.O uso da virtualização em centro de dados ou provedores de serviços ou mesmo em ambientes de computação em nuvem traz muitos benefícios. A virtualização, seja para serviços, aplicações ou servidores, não é mais uma tendência a ser uma realidade em muitos setores e áreas, seja dentro ou fora da área de tecnologia. Portanto, com esse uso emergente de virtualização, as empresas têm vindo a questionar muito sobre o desempenho e a segurança do uso de máquinas virtuais em infraestruturas de alta disponibilidade. Controlar o acesso às máquinas virtuais é um problema de segurança que todos os hypervisors possuem, como VmWare vSphere, Hyper-V ou KVM. Para tornar as máquinas virtuais mais seguras, a Microsoft introduziu as máquinas virtuais blindadas. Neste sentido, esta dissertação apresenta um estudo sobre conceitos-chave por trás de máquinas virtuais, Guarded Fabric, Host Guardian Service, Guarded Hosts e máquinas virtuais Blindadas. Uma Máquina Virtual Blindada é um recurso da Geração 2 (com suporte no Windows Server 2012 e posterior) que vem com um Trusted Platform Module (TPM) virtual, e que apenas pode ser executada em hospedeiros protegidos e aprovados na fabric e é criptografada usando o BitLocker. Para dar suporte ao nosso estudo foi configurado um ambiente de teste experimental, envolvendo um failover cluster com virtualização nativa ao nível de hardware com o Windows Server 2016 Hyper-V. No ambiente de teste, foi implementado e configurado um failover cluster, FreeNAS Storage, iSCSI Target, Máquinas Virtuais, Guarded Fabric e Máquinas Virtuais Blindadas. Após a implementação do ambiente de teste, um conjunto de testes e experiências foram realizados para estudar as implicações dos desempenhos das máquinas virtuais versus máquinas virtuais Blindadas em Infraestruturas Virtualizadas de Alta Disponibilidade. Por fim, fizemos a análise nos resultados trabalhados através dos testes, de acordo com os conceitos definidos no segundo capítulo da dissertação e com o ambiente de teste implementado. Um conjunto de experiencias foram realizadas em máquinas virtuais regulares e máquinas virtuais blindadas para avaliar o desempenho em termos de CPU, RAM e velocidade de escrita no disco. Os resultados mostram que o uso de máquinas virtuais blindadas conduz a uma pequena degradação do desempenho em comparação com o uso de máquinas virtuais regulares, mas, por outro lado, também se verificou que as máquinas virtuais blindadas permitem restringir o acesso às máquinas virtuais apenas para correrem em hosts confiáveis, além de impedirem que administradores não autorizados e malwares comprometam a máquina virtual

Proactive Scheduling in Cloud Computing

Autonomic fault aware scheduling is a feature quite important for cloud computing and it is related to adoption of workload variation. In this context, this paper proposes an fault aware pattern matching autonomic scheduling for cloud computing based on autonomic computing concepts. In order to validate the proposed solution, we performed two experiments one with traditional approach and other other with pattern recognition fault aware approach. The results show the effectiveness of the scheme

A Coordination Model and Framework for Developing Distributed Mobile Applications

How to coordinate multiple devices to work together as a single application is one of the most important challenges for building a distributed mobile application. Mobile devices play important roles in daily life and resolving this challenge is vital. Many coordination models have already been developed to support the implementation of parallel applications, and LIME (Linda In a Mobile Environment) is the most popular member. This thesis evaluates and analyzes the advantages and disadvantages of the LIME, and its predecessor Linda coordination model. This thesis proposes a new coordination model that focuses on overcoming the drawbacks of LIME and Linda. The new coordination model leverages the features of consistent hashing in order to obtain better coordination performance. Additionally, this new coordination model utilizes the idea of replica mechanism to guarantee data integrity. A cross-platform coordination framework, based on the new coordination model, is presented by this thesis in order to facilitate and simplify the development of distributed mobile applications. This framework aims to be robust and high-performance, supporting not only powerful devices such as smartphones but also constrained devices, which includes IoT sensors. The framework utilizes many advanced concepts and technologies such as CoAP protocol, P2P networking, Wi-Fi Direct, and Bluetooth Low Energy to achieve the goals of high-performance and fault-tolerance. Six experiments have been done to test the coordination model and framework from di erent aspects including bandwidth, throughput, packages per second, hit rate, and data distribution. Results of the experiments demonstrate that the proposed coordination model and framework meet the requirements of high-performance and fault-tolerance

Performance measurement and analysis of PC based cluster server using SET of Architecture and modeling a scalable High performance cluster

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