Maurício A. Pillon

Customer-oriented diagnosis of memory provisioning for IaaS clouds

Infrastructure-as-a-service clouds enable customers to use computing resources in a flexible manner to satisfy their needs, and pay only for the allocated resources. One challenge for IaaS customers is the correct provisioning of their resources. Many users end up underprovisioning, hurting application performance, or overprovisioning, paying for resources that are not really necessary. Memory is an essential resource for any computing system, and is frequently a nperformance-limiting factor in cloud environments. In this work, we propose a model that enables cloud customers to determine whether the memory allocated to their virtual machines is correctly provisioned, underprovisioned, or overprovisioned. The model uses two metrics collected inside a VM, resident and committed memory, and defines thresholds for these metrics that characterize each provisioning level. Experimental results with Linux guests on Xen, running four benchmarks with different workloads and varying memory capacity, show that the model was able to accurately diagnose memory provisioning in 98% of the scenarios evaluated.

DReAM - a distributed result-aware monitor for Network Functions Virtualization

Network Functions Virtualization (NFV) is a key technology to reduce management costs as well as to improve scalability and elasticity of computer networks. Still, recent research efforts have been exposing additional management challenges. Concerning monitoring in particular, new types of entities and requirements are underexploited. To address these issues, we propose DReAM, a resource management architecture based on management by delegation and distributed monitoring, where each agent runs a diagnostic model to compute the network service state. In this paper, we describe DReAMs proposed architecture and its major components. We also discuss the feasibility of DReAM through experimental and analytical evaluations, where we observed application throughput, CPU utilization, communication overhead, scalability, and diagnosis complexity. We provide a trade-off analysis on the monitoring strategies in NFV scenarios. Our results indicate that a result-aware strategy is a better option when the monitored environment has more than 256 agents or when the diagnosis module induces at least 10% of CPU utilization.

A Cost Model for IaaS Clouds based on Virtual Machine Energy Consumption

Cloud Computing has revolutionized the software, platform and infrastructure provisioning. Infrastructure-as-a-Service (IaaS) providers offer on-demand and configurable Virtual Machine (VMs) to tenants of cloud computing services. A key consolidation force that widespread IaaS deployment is the use of pay-as-you-go and pay-as-you-use cost models. In these models, a service price can be composed of two dimensions: the individual consumption, and a proportional value charged for service maintenance. A common practice for public providers is to dilute both capital and operational costs on predefined pricing sheets. In this context, we propose PSVE (Proportional-Shared Virtual Energy), a cost model for IaaS providers based on CPU energy consumption. Aligned with traditional commodity prices, PSVE is composed of two key elements: an individualized cost accounted from CPU usage of VMs (e.g., processing and networking), and a shared cost from common hypervisor management operations, proportionally distributed among VMs.

A Taxonomy Model for Single Sign-on Oriented towards Cloud Computing.

Clouds can be seen as a natural evolution of the Internet, allowing the utilization of computing capabilities maintained by third parties for optimizing resource usage. There are several elements that compose the cloud infrastructure and its services, and all of them must operate harmoniously. In particular, to allow the creation and deployment of services resilient to internal and external threats, the observance of security aspects is essential. This includes the deployment of authentication and authorization mechanisms to control the access to resources allocated on-demand, a strong requirement for any cloud-based solution. With this issue in mind, several providers have recently started using some form of Single Sign-On (SSO) mechanism to simplify the process of handling credentials inside the cloud. In this work, aiming to provide a structured overview of the wide variety of mechanisms that can be employed with this purpose, we propose a classification of SSO systems for cloud services, which can be used as a model for comparing current and future designing instances of such mechanisms. In addition, to validate the usefulness of the proposed taxonomy, we provide a classification of existing cloud-oriented SSO solutions.

An architecture for synchronising cloud file storage and organisation repositories

ABSTRACT Cloud computing providers have disseminated dynamic storage provisioning delivered to end users as on-demand services. Although cloud file storage and sharing has become popular among home users, the access requirements, performance expectations and usage characteristics are different for organisations, and were not originally considered by popular applications and tools for synchronising files between cloud providers and local repositories. Moreover, multisite organisations traditionally have legacy file storage and wide-area networking solutions to support their business systems. Typically, the file repositories are replicated between sites using private communication links. The combination of legacy storage solutions interconnected through private links with cloud-based file storage is a challenging task. In this context, this paper introduces Cloud4NetOrg, a client architecture for cloud file storage and multisite repository synchronisation. We implemented prototypes of this architecture that interact with two popular cloud file services (DropBox and OneDrive), and the experimental results indicate a promising application in collaborative environments with several LANs. Indeed, Cloud4NetOrg decreases the synchronisation time and the total data transferred from/to cloud repositories by using the organisation repositories as a hierarchical cache system. Cloud4NetOrg is proposed for geographically distributed organisations composed of dynamic and temporary collaborative groups. The interaction between employees is based on file sharing. Commonly, sites are interconnected by a private network and have an internal data storage repository. A single site can have multiple subnetworks to interconnect the collaborative groups. In addition, home-office users collaborate through the Internet, usually using size-limited storage devices. GRAPHICAL ABSTRACT

MeHarCEn: Um Método de Harmonização do Consumo de Energia em Data Centers

O consumo energetico controlado e eficiente e um desafio enfrentado diariamente pelos gestores de Data Centers de pequeno, medio e grande porte. A literatura especializada e tecnica define diversos guias, equipamentos e mecanismos para essa finalidade. Entretanto, a aplicacao combinada dessas solucoes e uma tarefa complexa, que, em muitos casos, requer um elevado investimento financeiro. Nesse contexto, o presente trabalho propoe o MeHarCEn, uma iniciativa para gerenciamento combinado e harmonico do consumo de energia em Data Centers. MeHarCEn nao depende de solucoes proprietarias e pode ser adaptado a Data Centers com configuracoes distintas. Aplicado a um estudo de caso, um DC de pequeno porte, o MeHarCEn resulta em uma economia de 52,7% no consumo de energia com climatizacao.

GreenHop: Open source environmental monitoring for small and medium data centers

Several organizations carry out the execution of their systems and data processing services in local processing centers, i.e., data centers (DC). However, small to medium — sized organizations usually do not have technical and financial conditions to monitor the climatic conditions of their DC. Thus, this may imply from excessive energy costs, drastic reduction of the life spam of the equipment and the incorrect processing of data and systems. In this paper we present the open source based solution GreenHop that aims to perform environmental monitoring of the DC server room. This paper presents four tests with different temperature settings, which is also included the application of free cooling method. We present a comparison of the energy impact of all settings. Thus, we aim to provide ambiental monitoring of the DC server room while we keep the system customizable to implement and replicate.

Diagnosing Memory Provisioning in IaaS Clouds

Infrastructure-as-a-service (IaaS) clouds enable customers to allocate computing resources in a flexible manner to satisfy their needs, and pay only for the allocated resources. One of the challenges for IaaS customers is the correct provisioning of their resources. Many users end up under provisioning, hurting application performance, or over provisioning, paying for resources that are not really necessary. Memory is an essential resource for any computing system, and is frequently a performance-limiting factor in cloud environments. Our work uses monitoring to enable a cloud customer to determine if the memory allocated to his virtual machines is correctly provisioned, under provisioned, or over provisioned. Experimental results with the Xen platform demonstrate the effectiveness of the proposed approach.