Technology market is continuing a rapid growth phase where different resource providers and Cloud Management Frameworks are positioning to provide ad-hoc solutions-as management interfaces, information discovery or billing-trying to differentiate from competitors resulting in incompatibilites between them when addressing more complex scenarios like federated clouds.Therefore, grasping interoperability problems present in current infrastructures by studying how existing and emerging standards could enhance the cloud user experience.In this paper we will review the current open challenges in Infrastructure as a Service cloud interoperability and federation, as well as point to the potential standards that should alleviate these problems. We will describe the main challenges regarding cloud federation and in-teroperability.We will showcase and review the existing and emerging standards that can be use to tackle the gaps in cloud federations.
@cite_1 work surveyed the existing standards for the management of cloud computing services and infrastructure within the Contrail project so as to avoid vendor lock-in issues and ensure interoperability. In the same line, @cite_29 performed a quite complete survey regarding Infrastructure as a Service access, management and interoperability, studying OVF, CDMI and OCCI @cite_29 . However, they have not entered into other details and challenges such as accounting or information discovery.
@cite_29 @cite_1
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Cloud computing providers have setup several data centers at different geographical locations over the Internet in order to optimally serve needs of their customers around the world However, existing systems do not support mechanisms and policies for dynamically coordinating load distribution among different Cloud-based data centers in order to determine optimal location for hosting application services to achieve reasonable QoS levels Further, the Cloud computing providers are unable to predict geographic distribution of users consuming their services, hence the load coordination must happen automatically, and distribution of services must change in response to changes in the load To counter this problem, we advocate creation of federated Cloud computing environment (InterCloud) that facilitates just-in-time, opportunistic, and scalable provisioning of application services, consistently achieving QoS targets under variable workload, resource and network conditions The overall goal is to create a computing environment that supports dynamic expansion or contraction of capabilities (VMs, services, storage, and database) for handling sudden variations in service demands. This paper presents vision, challenges, and architectural elements of InterCloud for utility-oriented federation of Cloud computing environments The proposed InterCloud environment supports scaling of applications across multiple vendor clouds We have validated our approach by conducting a set of rigorous performance evaluation study using the CloudSim toolkit The results demonstrate that federated Cloud computing model has immense potential as it offers significant performance gains as regards to response time and cost saving under dynamic workload scenarios. Emerging Cloud computing infrastructures provide computing resources on demand based on postpaid principles. For example, the RESERVOIR project develops an infrastructure capable of delivering elastic capacity that can automatically be increased or decreased in order to cost-efficiently fulfill established Service Level Agreements. This infrastructure also makes it possible for a data center to extend its total capacity by subcontracting additional resources from collaborating data centers, making the infrastructure a federation of Clouds. For accounting and billing, such infrastructures call for novel approaches to perform accounting for capacity that varies over time and for services (or more precisely virtual machines) that migrate between physical machines or even between data centers. For billing, needs arise for new approaches to simultaneously manage postpaid and prepaid payment schemes for capacity that varies over time in response to user needs. In this paper, we outline usage scenarios and a set of requirements for such infrastructures, and propose an accounting and billing architecture to be used within RESERVOIR. Even though the primary focus for this architecture is accounting and billing between resource consumers and infrastructure provides, future support for inter-site billing is also taken into account. A key advantage of infrastructure-as-a-service (IaaS) clouds is providing users on-demand access to resources. To provide on-demand access, however, cloud providers must either significantly overprovision their infrastructure (and pay a high price for operating resources with low utilization) or reject a large proportion of user requests (in which case the access is no longer on-demand). At the same time, not all users require truly on-demand access to resources. Many applications and workflows are designed for recoverable systems where interruptions in service are expected. For instance, many scientists utilize high-throughput computing (HTC)-enabled resources, such as Condor, where jobs are dispatched to available resources and terminated when the resource is no longer available. We propose a cloud infrastructure that combines on-demand allocation of resources with opportunistic provisioning of cycles from idle cloud nodes to other processes by deploying backfill virtual machines (VMs). For demonstration and experimental evaluation, we extend the Nimbus cloud computing toolkit to deploy backfill VMs on idle cloud nodes for processing an HTC workload. Initial tests show an increase in IaaS cloud utilization from 37.5 to 100 during a portion of the evaluation trace but only 6.39 overhead cost for processing the HTC workload. We demonstrate that a shared infrastructure between IaaS cloud providers and an HTC job management system can be highly beneficial to both the IaaS cloud provider and HTC users by increasing the utilization of the cloud infrastructure (thereby decreasing the overall cost) and contributing cycles that would otherwise be idle to processing HTC jobs. Cloud Infrastructure as a Service (IaaS), where traditional IT infrastructure resources such as compute, storage and networking are owned by a cloud service provider (CSP) and offered as on-demand virtual resources to customers (tenants), is the fastest maturing service model in cloud computing. The transformation of physical resources into virtual offers great flexibility to CSP customers including network based remote collaborative administration. This flexibility can be fully availed only if complemented by commensurately flexible access control to the customers remote IT resources by the customer's IT users. Since customer policies in this regard can vary greatly, the CSP needs a flexible model to accommodate diverse policy requirements. In this paper, we investigate attribute-based access control (ABAC) in cloud IaaS. In ABAC, access requests are evaluated based on the attributes of cloud tenant users and those of objects such as virtual machines, storage volumes, networks, etc. We investigate the access control models supported by commercial IaaS providers such as Amazon AWS and opensource OpenStack, as well as other models in the literature, which mostly use role-based access control (RBAC). We demonstrate their limitations and motivate the need for ABAC support to realize the true potential of IaaS. Building on prior published ABAC models we define a formal ABAC model suitable for IaaS. As proof-of-concept we implement this model in OpenStack, a widely-used open source cloud IaaS software platform. We discuss enforcement alternatives in this context and partially evaluate their performance.