Lámpsakos | No. 7 | PP. 47-57 | enero-junio | 2012 | ISSN: 2145-4086 | Medellín - Colombia CLOUD COMPUTING: A REVIEW OF PAAS, IAAS, SAAS SERVICES AND PROVIDERS CLOUD COMPUTING: UNA REVISIÓN DE LOS SERVICIOS Y PROVEEDORES PAAS, IAAS, SAAS Mg. María Salas-Zárate Mg. Luis Colombo-Mendoza Instituto Tecnológico de Orizaba, México Instituto Tecnológico de Orizaba, México [email protected] [email protected] (Review Article. Received el 17/10/2011. Accepted el 19/12/2011) Abstract. Cloud computing has become an Resumen. La computación en la nube se ha convertido important factor for businesses, developers, workers, en uno de los factores relevantes para las empresas, because it provides tools and Web applications that desarrolladores y trabajadores, porque proporciona allows storing information on external servers. Also, herramientas y aplicaciones web que permite almacenar Cloud computing offers advantages such as: cost información en servidores externos. Además, la reduction, information access from anywhere, to computación en la nube ofrece ventajas tales como: mention but a few. Nowadays, there are several reducción de costos, acceso a la información desde Cloud computing providers such as: Google Apps, cualquier lugar, por mencionar sólo algunos. Hoy en Zoho, AppEngine, Amazon E2C, among others. día hay varios proveedores de computación en la nube These providers offer Software, Infrastructure or como: Google Apps, Zoho, AppEngine, E2C Amazon, Platform as a Service. Taking this into account, this entre otros. Estos proveedores ofrecen software, paper presents a general review of Cloud computing infraestructura o plataforma como un servicio. En providers in order to allow users, enterprises, and este trabajo se presenta una revisión general de los developers select the one that meets their needs. proveedores de computación en la nube, con el fin de permitir a los usuarios, empresas y desarrolladores Keywords: Cloud computing, IaaS, PaaS, SaaS. seleccionar el que se ajuste a sus necesidades.. Palabras clave: Computación en la nube; IaaS, PaaS, SaaS. 48 María Salas-Zárate y Luis Colombo-Mendoza 1. INTRODUCTION improve the usability, maintainability and efficiency of services targeting Clouds with strict QoS constraints. Cloud computing is a new style of computing in which In [5] propose a taxonomy which identifies and dynamically scalable and often virtualized resources classifies eight important elements that characterize are provided as a services over the Internet [1]. Cloud computing infrastructures: 1) service type, According to who owns and manages the Cloud 2) resource deployment, 3) hardware, 4) runtime services, these can be classified in: Public, Private tuning, 5) security, 6) business model, 7) middle- and Hybrid Clouds. Public Cloud offers services to ware, and 8) performance. The taxonomy is based general public, unlike Private Cloud that are used by on a survey conducted on an important set of seven a single organization. Also, there are Hybrid Clouds IaaS providers, six Web hosting companies, and two which offer a combination of private and public mixed PaaS and Web hosting providers. In [6] present Clouds. Furthermore, there are three Cloud services a Cloud services comparison based on aspects such models: 1) SaaS (Software as a Service), 2) PaaS as architecture, features, and application. In [7] (Platform as a Service) and 3) IaaS (Infrastructure as present a survey of Cloud computing, highlighting its a Service). IaaS offers an infrastructure of resources key concepts, architectural principles, state-of-the- (storage, databases, among others), usually in terms art, implementation as well as research challenges. of Virtual machine as a service. PaaS offers an Also, they provide a better understanding of the environment oriented to the development, testing, design challenges of Cloud computing and they deployment and hosting of applications. SaaS offers identify important research directions in this area. In a set of applications installed and running over [8] examine the available Cloud computing services Internet. This paper presents a review of PaaS, SaaS and propose a tree-structured taxonomy which offers and IaaS providers, with the aim of helping users to a common terminology and baseline information for select the provider that best suits their needs and easy communication. In [9] analyze public quality budget. information of Cloud services in terms of service types, also they show that IaaS quality information This work is structured as follows. In section 2 related is more detailed and balanced than those of PaaS works of Cloud computing are discussed. Section and SaaS. In [10] present a detailed comparison 3 presents the architecture and features of Cloud of Cloud services according to the Cloud types, computing. Section 4 presents the public, private and interfaces, compatibility, implementation, deployment hybrid Cloud services. In section 5 a comparison of requirement and development support. IaaS, SaaS and PaaS providers is presented. Finally, we present our conclusions and emphasize our contribution. 3. CLOUD COMPUTING According to NIST(National Institute of standards and 2. RELATED WORK Technology) Cloud computing is defined as a model for enabling convenient, on-demand network access In [2] discuss both features and benefits of Cloud to a shared pool of configurable computing resources computing, and the Infrastructure as a Service (IaaS). (e.g., networks, servers, storage, applications, Also, they provide a means of understanding and and services) that can be rapidly provisioned and investigating IaaS. They outline the responsibilities of released with minimal management effort or service IaaS providers and the facilities to IaaS consumers. provider interaction [11]. In [3] present the design of a trusted Cloud computing The aforementioned definition has been adopted by platform (TCCP) that enables IaaS services such a great number of authors. Next, a Cloud computing as Amazon EC2 to provide a closed box execution general architecture is presented. environment. TCCP guarantees confidential execution of guest Virtual Machines, and allows 3.1 Cloud Computing Architecture users attesting the IaaS provider and determining if the service is secure before they launch their Virtual A Cloud computing architecture consists of four Machines In [4] describe a PaaS architecture for layers: Hardware, Infrastructure, Platforms and provisioning of real-time service-oriented application Application. This general architecture is shown in in Clouds. Also, they show how the combination Fig. 1. of methods, tools and services can be used to Lámpsakos | No. 7 | enero-junio 2012 Cloud Computing: A review of PaaS, IaaS, SaaS Service and Providers 49 The layers of this Cloud computing architecture are standard mechanisms by heterogeneous thin or described below. thick client platforms such as mobile phones, tablets, laptops, and workstations. Resource pooling: The provider’s computing resources are pooled in order to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to the consumer demand. There is a sense of location independence in that the customer has not control or knowledge over the exact location of the provided resources but he may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of Fig. 1 Cloud computing architecture resources are storage, processing, memory, and network bandwidth. Hardware layer: It manages the physical resources of the Cloud, including physical servers, routers, Rapid elasticity: Capabilities can be elastically switches, power and cooling systems. provisioned and released, in some cases, to scale rapidly outward and inward commensurate with Infrastructure or Virtualization layer: It creates demand. To the consumer, the capabilities available a pool of storing and computing resources by for provisioning often appear to be unlimited and can partitioning the physical resources using virtualization be appropriated in any quantity at any time. technologies such as VMware [12], Xen [13], and KVM [14]. Measured service: Cloud systems automatically control and optimize resource use by leveraging Platform layer: It is composed of operating systems a metering capability at some level of abstraction and application frameworks. Its aim is to minimize appropriate to the type of service (e.g., storage, the burden of deploying applications directly in VM processing, bandwidth, and active user accounts). containers. Resource usage can be monitored, controlled, and reported, providing transparency for both the Application layer: It consists of the actual Cloud provider and consumer of the utilized service [11]. applications. In contrast to traditional applications, Cloud applications can leverage the automatic- 4. CLOUD TYPES scaling feature to achieve better performance, availability and lower operating cost [7]. There are three kinds of Cloud computing services, which vary according to who owns and manages Next, the main features of Cloud computing are them. Next, these are described. described. Private Clouds or internal Clouds: It exclusively 3.4 Cloud computing features offers Cloud services for business or organizations that prefer to keep their data in a more controlled and : A consumer can be On-demand self-service secure environment. unilaterally provided of computing capabilities Public Clouds or external Clouds: It is the most information such