AndreiS.Braga GeraldoM.Silva MarcosC.Barrosducatte/mo401/1s2012/T2/G08-079740-ap.pdf · CloudComputing Universidade Estadual de Campinas AndreiS.Braga(RA 079713) GeraldoM.Silva(RA

Cloud Computing

Universidade Estadual de Campinas

Andrei S. Braga (RA 079713)

Geraldo M. Silva (RA 079740)

Marcos C. Barros (RA 820650)

20 de junho de 2012

Introdução à Cloud Computing Tecnologias Relacionadas Cloud Computing e Arq. de Computadores Desafios

Conteúdo

1 Introdução à Cloud Computing

2 Tecnologias Relacionadas

3 Cloud Computing e Arq. de Computadores

4 Desafios

2 / 21Cloud Computing


Introdução

Definição - Cloud computingCloud computing é um modelo para prover acesso ubíquo, conve-niente e sob demanda, via rede, a um conjunto compartilhado derecursos computacionais configuráveis (e.g., redes, servidores, arma-zenamento, aplicações e serviços) que podem ser alocados e desalo-cados de maneira rápida e com mínimo esforço de gerenciamento ouinteração do provedor do serviço.

Fonte: National Institute of Standards and Technology.



ArquiteturaO ambiente pode ser dividido em quatro camadas:

J Internet Serv Appl (2010) 1: 7–18 9

virtualized resources for high-level applications. A virtual-ized server is commonly called a virtual machine (VM). Vir-tualization forms the foundation of cloud computing, as itprovides the capability of pooling computing resources fromclusters of servers and dynamically assigning or reassigningvirtual resources to applications on-demand.

Autonomic Computing: Originally coined by IBM in2001, autonomic computing aims at building computing sys-tems capable of self-management, i.e. reacting to internaland external observations without human intervention. Thegoal of autonomic computing is to overcome the manage-ment complexity of today’s computer systems. Althoughcloud computing exhibits certain autonomic features suchas automatic resource provisioning, its objective is to lowerthe resource cost rather than to reduce system complexity.

In summary, cloud computing leverages virtualizationtechnology to achieve the goal of providing computing re-sources as a utility. It shares certain aspects with grid com-puting and autonomic computing but differs from them inother aspects. Therefore, it offers unique benefits and im-poses distinctive challenges to meet its requirements.

3 Cloud computing architecture

This section describes the architectural, business and variousoperation models of cloud computing.

3.1 A layered model of cloud computing

Generally speaking, the architecture of a cloud comput-ing environment can be divided into 4 layers: the hard-ware/datacenter layer, the infrastructure layer, the platformlayer and the application layer, as shown in Fig. 1. We de-scribe each of them in detail:

The hardware layer: This layer is responsible for man-aging the physical resources of the cloud, including phys-ical servers, routers, switches, power and cooling systems.In practice, the hardware layer is typically implementedin data centers. A data center usually contains thousandsof servers that are organized in racks and interconnectedthrough switches, routers or other fabrics. Typical issuesat hardware layer include hardware configuration, fault-tolerance, traffic management, power and cooling resourcemanagement.

The infrastructure layer: Also known as the virtualiza-tion layer, the infrastructure layer creates a pool of storageand computing resources by partitioning the physical re-sources using virtualization technologies such as Xen [55],KVM [30] and VMware [52]. The infrastructure layer is anessential component of cloud computing, since many keyfeatures, such as dynamic resource assignment, are onlymade available through virtualization technologies.

The platform layer: Built on top of the infrastructurelayer, the platform layer consists of operating systems andapplication frameworks. The purpose of the platform layeris to minimize the burden of deploying applications directlyinto VM containers. For example, Google App Engine oper-ates at the platform layer to provide API support for imple-menting storage, database and business logic of typical webapplications.

The application layer: At the highest level of the hierar-chy, the application layer consists of the actual cloud appli-cations. Different from traditional applications, cloud appli-cations can leverage the automatic-scaling feature to achievebetter performance, availability and lower operating cost.

Compared to traditional service hosting environmentssuch as dedicated server farms, the architecture of cloudcomputing is more modular. Each layer is loosely coupledwith the layers above and below, allowing each layer toevolve separately. This is similar to the design of the OSI

Fig. 1 Cloud computingarchitecture

Fonte: [Zhang et al., 2010]



Modelo de negócios

Cloud computing emprega um modelo de negócios sob demandaorientado a serviços. Tais serviços podem ser agrupados em trêscategorias:

Infrastructure as a Service (IaaS)

Platform as a Service (PaaS)

Software as a Service (SaaS)

Modelo de negócios

10 J Internet Serv Appl (2010) 1: 7–18

model for network protocols. The architectural modularityallows cloud computing to support a wide range of applica-tion requirements while reducing management and mainte-nance overhead.

3.2 Business model

Cloud computing employs a service-driven business model.In other words, hardware and platform-level resources areprovided as services on an on-demand basis. Conceptually,every layer of the architecture described in the previous sec-tion can be implemented as a service to the layer above.Conversely, every layer can be perceived as a customer ofthe layer below. However, in practice, clouds offer servicesthat can be grouped into three categories: software as a ser-vice (SaaS), platform as a service (PaaS), and infrastructureas a service (IaaS).

1. Infrastructure as a Service: IaaS refers to on-demandprovisioning of infrastructural resources, usually in termsof VMs. The cloud owner who offers IaaS is called anIaaS provider. Examples of IaaS providers include Ama-zon EC2 [2], GoGrid [15] and Flexiscale [18].

2. Platform as a Service: PaaS refers to providing platformlayer resources, including operating system support andsoftware development frameworks. Examples of PaaSproviders include Google App Engine [20], MicrosoftWindows Azure [53] and Force.com [41].

3. Software as a Service: SaaS refers to providing on-demand applications over the Internet. Examples of SaaSproviders include Salesforce.com [41], Rackspace [17]and SAP Business ByDesign [44].

The business model of cloud computing is depicted byFig. 2. According to the layered architecture of cloud com-puting, it is entirely possible that a PaaS provider runs itscloud on top of an IaaS provider’s cloud. However, in thecurrent practice, IaaS and PaaS providers are often parts ofthe same organization (e.g., Google and Salesforce). This iswhy PaaS and IaaS providers are often called the infrastruc-ture providers or cloud providers [5].

Fig. 2 Business model of cloud computing

3.3 Types of clouds

There are many issues to consider when moving an enter-prise application to the cloud environment. For example,some service providers are mostly interested in lowering op-eration cost, while others may prefer high reliability and se-curity. Accordingly, there are different types of clouds, eachwith its own benefits and drawbacks:

Public clouds: A cloud in which service providers of-fer their resources as services to the general public. Pub-lic clouds offer several key benefits to service providers, in-cluding no initial capital investment on infrastructure andshifting of risks to infrastructure providers. However, pub-lic clouds lack fine-grained control over data, network andsecurity settings, which hampers their effectiveness in manybusiness scenarios.

Private clouds: Also known as internal clouds, privateclouds are designed for exclusive use by a single organiza-tion. A private cloud may be built and managed by the orga-nization or by external providers. A private cloud offers thehighest degree of control over performance, reliability andsecurity. However, they are often criticized for being simi-lar to traditional proprietary server farms and do not providebenefits such as no up-front capital costs.

Hybrid clouds: A hybrid cloud is a combination of publicand private cloud models that tries to address the limitationsof each approach. In a hybrid cloud, part of the service in-frastructure runs in private clouds while the remaining partruns in public clouds. Hybrid clouds offer more flexibilitythan both public and private clouds. Specifically, they pro-vide tighter control and security over application data com-pared to public clouds, while still facilitating on-demandservice expansion and contraction. On the down side, de-signing a hybrid cloud requires carefully determining thebest split between public and private cloud components.

Virtual Private Cloud: An alternative solution to address-ing the limitations of both public and private clouds is calledVirtual Private Cloud (VPC). A VPC is essentially a plat-form running on top of public clouds. The main difference isthat a VPC leverages virtual private network (VPN) technol-ogy that allows service providers to design their own topol-ogy and security settings such as firewall rules. VPC is es-sentially a more holistic design since it not only virtualizesservers and applications, but also the underlying commu-nication network as well. Additionally, for most companies,VPC provides seamless transition from a proprietary serviceinfrastructure to a cloud-based infrastructure, owing to thevirtualized network layer.

For most service providers, selecting the right cloudmodel is dependent on the business scenario. For exam-ple, computation-intensive scientific applications are bestdeployed on public clouds for cost-effectiveness. Arguably,certain types of clouds will be more popular than others.

Fonte: [Zhang et al., 2010]



Características

Caraterísticas de cloud incluem:

Multi-tenancyConjunto de recursos compartilhado (Shared resource pooling)Geodistribuição e acesso ubíquoOrientação a serviçosAlocação dinâmica de serviçosAuto-organizáveisPreço baseado em utilização (Utility-based pricing)



Tecnologias relacionadas

Grande confusão é gerada em relação a cloud e outras tecnologias,como:

Cluster computing:

Grid computing:




Grande confusão é gerada em relação a cloud e outras tecnologias,como:

Cluster computing:Grid computing:




A tabela abaixo relaciona cloud, grid e cluster:

Características Cloud Grid ClusterUsabilidade Sim Parcial NãoVirtualização Sim Parcial ParcialPadronização Não Sim SimMulti-tenancy Sim Sim NãoSelf-service Sim Sim Não

Escalabilidade Sim Parcial NãoInteroperabilidade Parcial Sim Sim

Segurança Não Parcial SimComputação Sob Demanda Alta Alta

Fonte: [Sadashiv and Kumar, 2011]



Cloud computing e arq. de computadores

Intel Single-Chip Cloud Computer (48-core SCC);

Criado para ser utilizado pela comunidade científica para explorar fu-turas arquiteturas de mais de 100 cores num mesmo chip, as maneirasde como conectá-los e como criar programas para estas arquiteturas;

Duas características principais:

Memória de passagem de mensagem - consistência de dados mantidapor software;Controle de consumo de energia - ajuste de tensão e frequência deoperação.



Intel SCC - Arquitetura

48 Pentium cores (P54C execuçãoem ordem) divididos em 24 bancos,de 2 cores cada;

rede interna (Network On Chip) detopologia em malha 2D retangular6x4;

4 controladores de memória doubledata rate tipo 3 (DDR3) com acessoa 64GB no total;

Interface de sistema que se co-necta a um dispositivo FPGA ex-terno para comunicação PCI-e eEthernet MACs a dispositivos deI/O;

Arquitetura

Fonte: [Howard et al., 2010, Gries et al., 2011]



Intel SCC - Core

2 cores P54C;

Cada core 16KB cache L1 ins-trução e 16KB cache L1 dados256KB de cache L2 unificada;

1 Memória de Passagem de Men-sagem (MPB) SRAM de 16KB;

1 Interface de Rede Unificada(MIU);

Arquitetura

Fonte: [Mattson et al., 2010]



Intel SCC - MemóriaCada controlador de memória DDR3 pode ser conectado a até doismódulos de memória tipo dual-inline de 8GB;Total memória externa 64GB;Tabela de configuração de página mapeia o endereço 32 bits de cadapágina de 16MB em um endereço de 34 bits e indica qual o contro-lador DDR3 deve ser utilizado pela página indicada;Um bit na tabela de configuração de cada página para indicar se apágina pode ser espelhada na cache e um bit para indicar se a páginaé do tipo de memória de passagem de mensagem.

Fonte: [Gries et al., 2011]



Intel SCC - Memória

Memória DRAM externa ex-clusiva associada a cada core;

Memória DRAM externacompartilhada;

Memória SRAM interna com-partilhada (MPB).

Memória

Fonte: [Mattson et al., 2010]



Intel SCC - Memória

Unidade de Interface de Rede(I/F Rede) realiza o controle deacesso à memória;

Memória externa: captura mis-ses de acesso na cache L1 e nacache L2 e redireciona o acessoao controlador de memória ex-terna;

Memória de Passagem de Men-sagem: captura miss na cacheL1, cancela o acesso a cache L2e redireciona o acesso à memóriade passagem de mensagem;

Memória




Intel SCC – Comunicação

Uma nova instrução adicionada aoconjunto de instruções INVDMB;

Invalida o conteúdo de todas as li-nhas da cache L1 correspondentesa memória de passagem de mensa-gem;

Core A executa instrução INVDMBantes da escrita;

Core B executa instrução INVDMBantes da leitura.

Memória

Fonte: [Howard et al., 2010]



Intel SCC – Tensão

8 domínios de tensão independen-tes;

Ajuste de tensão de 0 a 1.3V empassos de 6.25mV em milisegundos;

Desliga completamente um con-junto de 4 cores, ou coloca em modode espera de baixo consumo a 0.7Vpreservando o conteúdo dos regis-tradores e memória cache;

Células de isolação e conversão denível de tensão são utilizadas paraintegrar os diferentes domínios detensão.

Domínio de tensão




Intel SCC – Frequência

28 domínios de frequência independentes;

um para cada core, um para a rede, um para os controladores dememória DDR3, um para a interface do sistema e um para os con-troladores de reguladores de tensão;

Filas determinísticas do tipo FIFO são utilizadas para sincronizar osdiferentes domínios de freqüência;

A frequência máxima para os cores é de 1GHz a 1.1.V e para a redeé de 2GHz e pode ser ajustada para valores menores por divisoresinteiros que podem ir de 1 a 16 em questão de nanosegundos;

Através dos ajustes de tensão e frequência o processador podeconsumir de 25W a 125W.



Intel SCC – Desempenho

Fonte: [Totoni et al., 2012]



Intel SCC – Desempenho

Intel SCCbom resultado de compromisso entre desempenho e consumo, sendomais veloz que os processadores de baixo consumo, consumindo me-nos que os processadores heavy-weight, tendo maior compatibilidadecom programas existentes e maior facilidade de programação que osprocessadores GPGPUs.

Heavy-weightmelhor desempenho em programas irregulares, porém são os que têmo consumo mais elevado.

Low Powermais baixo consumo, porém o menor desempenho.

Highly Parallel - GPGPUsmelhor desempenho para programas regulares que apresentam altonível de paralelismo, sem um consumo de energia elevado, porém tema desvantagem de apresentar maior dificuldade de programação e nãocompatibilidade com programas já existentes no mercado, requerendoque muitas das aplicações sejam reescritas.



Desafios em cloud

Cloud é um paradigma recente e vários desafios estão em aberto:

Padronização:Alocação dinâmica de serviços:Migração de máquinas virtuais:Consolidação de servidores:Gerência de energia(green computing):Análise e gerência de tráfego:Mecanismos de segurança de informações:Frameworks de software:Tecnologias para armazenamento e gerência de informações:Novas arquiteturas para cloud:



[Gries et al., 2011] Gries, M., Hoffmann, U., Konow, M., and Riepen, M.(2011). Scc: A flexible architecture for many-core platform research.Computing in Science and Engg., 13(6):79–83.

[Howard et al., 2010] Howard, J., Dighe, S., Hoskote, Y., Vangal, S., Finan,D., Ruhl, G., Jenkins, D., Wilson, H., Borkar, N., Schrom, G., Pailet, F.,Jain, S., Jacob, T., Yada, S., Marella, S., Salihundam, P., Erraguntla, V.,Konow, M., Riepen, M., Droege, G., Lindemann, J., Gries, M., Apel, T.,Henriss, K., Lund-Larsen, T., Steibl, S., Borkar, S., De, V., VanDer Wijngaart, R., and Mattson, T. (2010). A 48-core ia-32message-passing processor with dvfs in 45nm cmos.In Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2010IEEE International, pages 108 –109.

[Mattson et al., 2010] Mattson, T., Van der Wijngaart, R., Riepen, M.,Lehnig, T., Brett, P., Haas, W., Kennedy, P., Howard, J., Vangal, S.,Borkar, N., Ruhl, G., and Dighe, S. (2010). The 48-core scc processor: theprogrammer’s view.In High Performance Computing, Networking, Storage and Analysis (SC),2010 International Conference for, pages 1–11.



[Sadashiv and Kumar, 2011] Sadashiv, N. and Kumar, S. (2011). “Cluster,grid and cloud computing: A detailed comparison”.In Computer Science Education (ICCSE), 2011 6th International Conferenceon, pages 477 –482.

[Totoni et al., 2012] Totoni, E., Behzad, B., Ghike, S., and Torrellas, J.(2012). Comparing the power and performance of intel’s scc tostate-of-the-art cpus and gpus.In Performance Analysis of Systems and Software (ISPASS), 2012 IEEEInternational Symposium on, pages 78 –87.

[Zhang et al., 2010] Zhang, Q., Cheng, L., and Boutaba, R. (2010). “Cloudcomputing: state-of-the-art and research challenges”.Journal of Internet Services and Applications, 1(1):7–18.



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AndreiS.Braga GeraldoM.Silva MarcosC.Barrosducatte/mo401/1s2012/T2/G08-079740-ap.pdf · CloudComputing Universidade Estadual de Campinas AndreiS.Braga(RA 079713) GeraldoM.Silva(RA