David Villegas

Cloud federation in a layered service model

We show how a layered Cloud service model of software (SaaS), platform (PaaS), and infrastructure (IaaS) leverages multiple independent Clouds by creating a federation among the providers. The layered architecture leads naturally to a design in which inter-Cloud federation takes place at each service layer, mediated by a broker specific to the concerns of the parties at that layer. Federation increases consumer value for and facilitates providing IT services as a commodity. This business model for the Cloud is consistent with broker mediated supply and service delivery chains in other commodity sectors such as finance and manufacturing. Concreteness is added to the federated Cloud model by considering how it works in delivering the Weather Research and Forecasting service (WRF) as SaaS using PaaS and IaaS support. WRF is used to illustrate the concepts of delegation and federation, the translation of service requirements between service layers, and inter-Cloud broker functions needed to achieve federation.

An Analysis of Provisioning and Allocation Policies for Infrastructure-as-a-Service Clouds

Today, many commercial and private cloud computing providers offer resources for leasing under the infrastructure as a service (IaaS) paradigm. Although an abundance of mechanisms already facilitate the lease and use of single infrastructure resources, to complete multi-job workloads IaaS users still need to select adequate provisioning and allocation policies to instantiate resources and map computational jobs to them. While such policies have been studied in the past, no experimental investigation in the context of clouds currently exists that considers them jointly. In this paper we present a comprehensive and empirical performance-cost analysis of provisioning and allocation policies in IaaS clouds. We first introduce a taxonomy of both types of policies, based on the type of information used in the decision process, and map to this taxonomy eight provisioning and four allocation policies. Then, we analyze the performance and cost of these policies through experimentation in three clouds, including Amazon EC2. We show that policies that dynamically provision and/or allocate resources can achieve better performance and cost. Finally, we also look at the interplay between provisioning and allocation, for which we show preliminary results.

Enabling Interoperability among Meta-Schedulers

Grid computing supports shared access to computing resources from cooperating organizations or institutes in the form of virtual organizations. Resource brokering middleware, commonly known as a meta-scheduler or a resource broker, matches jobs to distributed resources. Recent advances in meta- scheduling capabilities are extended to enable resource matching across multiple virtual organizations. Several architectures have been proposed for interoperating meta-scheduling systems. This paper presents a hybrid approach, combining hierarchical and peer-to-peer architectures for flexibility and extensibility of these systems. A set of protocols are introduced to allow different meta-scheduler instances to communicate over Web Services. Interoperability between three heterogeneous and distributed organizations (namely, BSC, FIU, and IBM), each using different meta-scheduling technologies, is demonstrated under these protocols and resource models.

Enabling Interoperability among Grid Meta-Schedulers

The goal of Grid computing is to integrate the usage of computer resources from cooperating partners in the form of Virtual Organizations (VO). One of its key functions is to match jobs to execution resources efficiently. For interoperability between VOs, this matching operation occurs in resource brokering middleware, commonly referred to as the meta-scheduler or meta-broker. In this paper, we present an approach to a meta-scheduler architecture, combining hierarchical and peer-to-peer models for flexibility and extensibility. Interoperability is further promoted through the introduction of a set of protocols, allowing meta-schedulers to maintain sessions and exchange job and resource state using Web Services. Our architecture also incorporates a resource model that enables an efficient resource matching across multiple Virtual Organizations, especially where the compute resources and state are dynamic. Experiments demonstrate these new functional features across three distributed organizations (BSC, FIU, and IBM), that internally use different job scheduling technologies, computing infrastructure and security mechanisms. Performance evaluations through actual system measurements and simulations provide the insights on the architecture’s effectiveness and scalability.

The Role of Grid Computing Technologies in Cloud Computing

The fields of Grid, Utility and Cloud Computing have a set of common objectives in harnessing shared resources to optimally meet a great variety of demands cost-effectively and in a timely manner Since Grid Computing started its technological journey about a decade earlier than Cloud Computing, the Cloud can benefit from the technologies and experience of the Grid in building an infrastructure for distributed computing. Our comparison of Grid and Cloud starts with their basic characteristics and interaction models with clients, resource consumers and providers. Then the similarities and differences in architectural layers and key usage patterns are examined. This is followed by an in depth look at the technologies and best practices that have applicability from Grid to Cloud computing, including scheduling, service orientation, security, data management, monitoring, interoperability, simulation and autonomic support. Finally, we offer insights on how these techniques will help solve the current challenges faced by Cloud computing.

Transparent grid enablement of weather research and forecasting

The impact of hurricanes is so devastating throughout different levels of society that there is a pressing need to provide a range of users with accurate and timely information that can enable effective planning for and response to potential hurricane landfalls. The Weather Research and Forecasting (WRF) code is the latest numerical model that has been adopted by meteorological services worldwide. The current version of WRF has not been designed to scale out of a single organizations local computing resources. However, the high resource requirements of WRF for fine-resolution and ensemble forecasting demand a large number of computing nodes, which typically cannot be found within one organization. Therefore, there is a pressing need for the Grid-enablement of the WRF code such that it can utilize resources available in partner organizations. In this paper, we present our research on Grid enablement of WRF by leveraging our work in transparent shaping, GRID superscalar, profiling, code inspection, code modeling, meta-scheduling, and job flow management.

DEVA: distributed ensembles of virtual appliances in the cloud

Low upfront costs, rapid deployment of infrastructure and flexible management of resources has resulted in the quick adoption of cloud computing. Nowadays, different types of applications in areas such as enterprise web, virtual labs and high-performance computing are already being deployed in private and public clouds. However, one of the remaining challenges is how to allow users to specify Quality of Service (QoS) requirements for composite groups of virtual machines and enforce them effectively across the deployed resources. In this paper, we propose an Infrastructure as a Service resource manager capable of allocating Distributed Ensembles of Virtual Appliances (DEVAs) in the Cloud. DEVAs are groups of virtual machines and their network connectivities instantiated on heterogeneous shared resources with QoS specifications for individual entities as well as their connections. We discuss the different stages in their lifecycle: declaration, scheduling, provisioning and dynamic management, and show how this approach can be used to maintain QoS for complex deployments of virtual resources.

Enabling Autonomic Meta-Scheduling in Grid Environments

Grid computing supports workload execution on computing resources that are shared across a set of collaborative organizations. At the core of workload management for grid computing is a software component, called meta-scheduler or grid resource broker, that provides a virtual layer on top of heterogeneous grid middleware, schedulers, and resources. Meta-schedulers typically enable end-users and applications to compete over distributed shared resources through the use of one or more instances of the same meta-scheduler, in a centralized or distributed manner, respectively. We propose an approach to enabling autonomic meta-scheduling through the use of a new communication protocol that -if adopted by different meta-schedulers or by the applications using them- can improve the workload execution while avoiding potential chaos, which can be resulted from blind competition over resources. This can be made possible by allowing the meta- schedulers and/or their applications to engage in a process to negotiate their roles (e.g., consumer, provider, or both), scheduling policies, service-level agreement, etc. To show the feasibility of our approach, we developed a prototype that enables some preliminary autonomic management among three different meta-schedulers, namely, GridWay, eNANOS, andTDWB.

An experimental system for grid meta-broker evaluation

Grid meta-broker is a key enabler in realizing the full potential of inter-operating grid computing systems. A challenge to properly evaluate the effectiveness of meta-brokers is the complexity of developing a realistic grid experimental environment. In this paper, this challenge is addressed by a unique combination of two approaches: using reduced workload traces to demonstrate the resource matching and scheduling functions of the meta-broker, and using emulation to provide a flexible and scalable modeling and management for local resources of a grid environment. Real workload traces are reduced while preserving their key workload characteristics to allow exploration of various dimensions of meta-broker functions in reasonable time. Evaluation of round-robin, queue-length, and utilization based meta-broker scheduling algorithms shows that they have different effects on various workloads.