UNIT 2 LECTURE 2

CLOUD INTEROPERABILITY AND STANDARD

Introduction

Cloud computing is rapidly growing in importance for many organizations, with ongoing take-up of a wide range of cloud services and the transition of both data and applications to cloud computing environments. The topics of interoperability and portability are significant considerations in relation to the use of cloud services, but there is also confusion and misunderstanding of exactly what this entails. The aim of this section is to provide a clear definition of interoperability and of portability and how these relate to various aspects of cloud computing and to cloud services.

Interoperability & Portability Overview

The cloud ecosystem is large, with many providers offering a wide variety of cloud services. Understanding the portability and interoperability “of what” is the necessary first step of planning and designing for the use of any cloud service. Clarifying the specific interoperability and portability concerns accelerates identification of the “best fit” options and potential development of solutions.

This section provides an overview of the topics of interoperability and portability which is useful in understanding the more detailed descriptions contained in the scenarios and subsequent sections.

Basic Definition of Interoperability

Broadly speaking, interoperability can be defined as a measure of the degree to which diverse systems or components can work together successfully.

More formally, IEEE and ISO define interoperability as the ability for two or more systems or applications to exchange information and mutually use the information that has been exchanged.

To be more concrete, in the context of cloud computing, interoperability should be viewed as the capability of public clouds, private clouds, and other diverse systems within the enterprise to understand each other’s application and service interfaces, configuration, forms of authentication and authorization, data formats etc. in order to cooperate and interoperate with each other.

In cloud computing, the most significant interacting components are those which belong to the cloud service customer which interact with components of the cloud service provider. The nature of the interaction is a network connection using a prescribed interface or API. There are typically multiple separate interfaces, each dealing with a different aspect of the cloud service. For example, there are the functional interfaces of the cloud service itself, authentication and authorization interfaces, interfaces for administration of the cloud services, and business interfaces for billing and invoicing. The ideal of interoperability is that the interfaces are standardized in some way – i.e. they are interoperable - so that the customer can switch to another cloud service provider with minimal impact on the customer's components.

 

Basic Definition of Portability

Portability is about the ability to move an entity from one system to another so that it is usable on the target system. The main problem caused by the lack of portability is that it may take considerable effort to transform the entity from its format on the source system to the format required by the target system.

Portability is divided into two separate areas: data portability and application portability: 

Cloud data portability is the ability to easily transfer data from one cloud service to another cloud service, without being required to re-enter the data. It is the ease of moving the data that is the essence here. This might be achieved by the source service supplying the data in exactly the format that is accepted by the target service. But even if the formats do not match, the transformation between them may be simple and straightforward to achieve with commonly available tools.

Application portability is the ability to easily transfer an application or application components from one cloud service to a comparable cloud service and run the application in the target cloud service. The ease of moving the application or application components is the key here. The application may require recompiling or relinking for the target cloud service, but it should not be necessary to make significant changes to the application code.

 Standards for Interoperability and Portability

To date, most of the focus for cloud interoperability and portability standards has been at the IaaS layer although activity at the PaaS level is starting to accelerate. In addition, there are several security standards that enable and facilitate cloud computing interoperability even though they are not exclusive to cloud computing. Cloud computing customers should determine the level of support for the following standards by prospective cloud service providers. Lack of support for these standards is likely to result in interoperability and portability challenges down the road.

·   Open Virtualization Format (OVF). A packaging standard developed by the Distributed Management Task Force (DMTF) that is designed to address the portability and deployment of virtual machines.

·         Cloud Data Management Interface (CDMI). A standard defined by the Storage Networking Industry Association (SNIA) that defines the functional interface that applications will use to create, retrieve, update and delete data elements from the cloud.

·         Open Cloud Computing Interface (OCCI). A set of open specifications delivered through the Open Grid Forum that defines a protocol and API for all kinds of cloud computing management tasks.

·         Topology and Orchestration Specification for Cloud Applications (TOSCA). A standard developed by OASIS that enables the interoperable description of application and infrastructure cloud services, the relationships between parts of the service, and the operational behavior of these services (e.g., deploy, patch, shutdown).

·         Cloud Application Management for Platforms (CAMP) . A standard developed by OASIS that defines an interoperable protocol that cloud implementers can use to package and deploy their applications.

·         Cloud Auditing Data Federation (CADF). A standards developed by DMTF that defines open standards for cloud auditing.

·         LDAP, OAuth, OpenID Connect and SAML. Standards that enable third party ID and Access Management functionality.

·         US FIPS 140-2. Standard that specifies the security requirements to be satisfied by a cryptographic module utilized within a security system protecting sensitive information.

In addition to standards, there are a number of open source projects that are having a positive impact on cloud computing interoperability and portability. Open source projects that have an open governance model (i.e. not controlled by a single company) and attract a broad supporting ecosystem are the best candidates for creating de facto standards. In the IaaS space, OpenStack is an example of an open source project that is building significant industry momentum. Open source projects for PaaS are emerging. Examples of PaaS open source projects that are starting to build significant industry support include Cloud Foundry, Heroku, OpenShift and Docker.

SCALABILITY & FAULT TOLERANCE

The ability to scale on demand constitutes one of the most attractive features of cloud computing. Clouds allow scaling beyond the limits of the existing in-house IT resources, whether they are Infrastructure (compute and storage) or applications services. To implement such a capability, the cloud middle ware has to be designed with the principle of scalability along different dimensions in mind—for example, performance, size, and load. The cloud middleware manages a huge number of resource and users, which rely on the cloud to obtain the horse power that they cannot obtain within the premises without bearing considerable administrative and maintenance costs. These costs are a reality for whoever develops, manages, and maintains the cloud middleware and offers the service to customers.

In this scenario, the ability to tolerate failure becomes fundamental, sometimes even more important than providing an extremely efficient and optimized system. Hence, the challenge in this case is designing highly scalable and fault-tolerant systems that are easy to manage and at the same time provide competitive performance.