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Virtualization Technology in Distributed Computing (VTDC), 2007 Second International Workshop on

Date 12-12 Nov. 2007

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Displaying Results 1 - 9 of 9
  • Enabling Semantic Communications for Virtual Machines via iConnect

    Publication Year: 2007 , Page(s): 1 - 8
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    iConnect is an abstraction that encapsulates all of a virtual machine's interactions with outside entities. Its intent is to exploit semantic information to better support the end-to-end requirements of such VM communications. Focusing on the I/O performed by VMs and leveraging the fact that modern systems already have to virtualize the physical devices used by VMs, this paper shows that the iConnect abstraction can be implemented with the extension of existing virtual device interfaces. Specifically, by devising enhanced virtual devices, we can (1) efficiently implement the communication paths between virtual machines (VMs) and the virtualized platforms (VPs) on which they run, and (2) capture semantic information about VM-device interactions, which can then be used to implement additional functionality and efficient sharing of physical devices. The paper presents three concrete realizations of the iConnect abstraction: a multimedia device virtualization solution (VMedia) which utilizes semantic information to implement efficient sharing and enhanced functionality, a network virtualization solution that provides virtual NICs with QoS-support where the VM communicates its QoS requirements to the VP, and a storage virtualization solution which permits a VM to access a block device regardless of whether such a device is physically located locally or must be accessed at a remote location. A Xen-based implementation of the iConnect concept demonstrates substantial performance improvements and additional functionality derived from their use at a minimal cost to VMs, in part because iConnect utilizes additional computational resources of the VP and can take better advantage of certain underlying platform capabilities. View full abstract»

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  • MemX: Supporting Large Memory Workloads in Xen Virtual Machines

    Publication Year: 2007 , Page(s): 1 - 8
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (434 KB) |  | HTML iconHTML  

    Modern grid computing and enterprise applications increasingly execute on clusters that rely upon virtual machines (VMs) to partition hardware resources and improve utilization efficiency. These applications tend to have memory and I/O intensive workloads, such as large databases, data mining, scientific workloads, and web services, which can strain the limited I/O and memory resources within a single VM. In this paper, we present our experiences in developing a fully transparent distributed system, called MemX, within the Xen VM environment that coordinates the use of cluster-wide memory resources to support large memory and I/O intensive workloads. Applications using MemX do not require specialized APIs, libraries, recompilation, relinking, or dataset pre-partitioning. We compare and contrast the different design choices in MemX and present preliminary performance evaluation using several resource-intensive benchmarks in both virtualized and non-virtualized Linux. Our evaluations show that large dataset applications and multiple concurrent VMs achieve significant speedups using MemX compared against virtualized local and iSCSI disks. As an added benefit, we also show that live Xen VMs using MemX can migrate seamlessly without disrupting any running applications. View full abstract»

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  • Safe Device Driver Model Based on Kernel-mode JVM

    Publication Year: 2007 , Page(s): 1 - 8
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (281 KB) |  | HTML iconHTML  

    Researches have shown that device drivers account for most of the OS kernel crashes. In this paper we proposed a safe device driver model for the Linux OS, aiming at gaining an improvement on its reliability. Within this model, we are able to write device drivers in the type-safe language of Java, rather than the traditional C. Our main work includes the design of kernel-mode JVM which is suitable for running device drivers and the programming model of Java device driver. During the evaluation, by manually injecting bugs and observing the running results, we can see that Java device driver can effectively prevent various bugs from damaging the kernel and thus improve the reliability of operating system, only at the price of some degradation on system performance, which helps to demonstrate the viability of our approach. Mention that although we based our research on Linux, Java device driver model can also be applied to other operating systems, as long as the device drivers are accessed through standardized interfaces. View full abstract»

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  • Taking Snapshots of Virtual Networked Environments

    Publication Year: 2007 , Page(s): 1 - 8
    Cited by:  Papers (5)  |  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (237 KB) |  | HTML iconHTML  

    The capture of global, consistent snapshots of a distributed computing session or system is essential to the system's reliability, manageability, and accountability. Despite the large body of work at the application, library, and operating system levels, we identify a void in the spectrum of distributed snapshot techniques: taking snapshots of the entire distributed runtime environment. Such capability has unique applicability in a number of application scenarios. In this paper, we realize such capability in the context of virtual networked environments. More specifically, by adapting and implementing a distributed snapshot algorithm, we enable the capture of causally consistent snapshots of virtual machines in a virtual networked environment. The snapshot-taking operations do not require any modification to the applications or operating systems running inside the virtual environment. Preliminary evaluation results indicate that our technique incurs acceptable overhead and small disruption to the normal operation of the virtual environment. View full abstract»

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  • Experimental Study of Virtual Machine Migration in Support of Reservation of Cluster Resources

    Publication Year: 2007 , Page(s): 1 - 8
    Cited by:  Papers (23)  |  Patents (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (614 KB) |  | HTML iconHTML  

    Virtual Machines are becoming increasingly valuable to resource consolidation and management, providing efficient and secure resource containers, along with desired application execution environments. This paper focuses on the VM-based resource reservation problem, that is, the reservations of CPU, memory and network resources for individual VM instances, as well as for VM clusters. In particular, it considers the scenario where one or several physical servers need to be vacated to start a cluster of VMs for dedicated execution of parallel jobs. VMs provide a primitive for transparently vacating workloads through migration; however, the process of migrating several VMs can be time-consuming and needs to be estimated. To achieve this goal, this paper seeks to provide a model that can characterize the VM migration process and predict its performance, based on a comprehensive experimental analysis. The results show that, given a certain VM's migration time, it is feasible to predict the time for a VM with other configurations, as well as the time for migrating a number of VMs. The paper also shows that migration of VMs in parallel results in shorter aggregate migration times, but with higher per-VM migration latencies. Experimental results also quantify the benefits of buffering the state of migrated VMs in main memory without committing to hard disks. View full abstract»

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  • Model-based Resource Selection for Efficient Virtual Cluster Deployment

    Publication Year: 2007 , Page(s): 1 - 7
    Cited by:  Papers (3)  |  Patents (8)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (719 KB) |  | HTML iconHTML  

    Virtual clusters on Grids can greatly extend the current scale and efficiency of high-performance Grid computing through more flexible usage of distributed heterogeneous resources. However, the overhead due to installing virtual clusters often precludes their applicability only to long-running applications. This is especially problematic on heterogeneous Grid environments, since installation time of each virtual node can vary greatly, and the total installation time of a virtual cluster is bottlenecked by the slowest node. To achieve fast virtual cluster installation even on such heterogeneous Grid environments, we propose a model-based resource selection policy that automatically identifies a near-optimal node combination to assemble each virtual cluster. We divide the VM setup process into five logical steps and construct a performance model for each step. The model represents the execution time of each step as a linear combination of hardware and software parameters, including CPU frequency, disk I/O performance, and installed package size. To evaluate the proposed resource selection policy, we have extended our own virtual cluster installer, VPC, to select nodes in the increasing order of predicted installation time. Experimental results show that the model-based selection policy is indeed effective, especially when the package size differs depending on sites. The proposed policy has shown to reduce the installation time by up to 68% compared to the most naïve policy that selects nodes in a random order, 60% and 58% to the policies considering either CPU speed or disk I/O performance, respectively. View full abstract»

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  • Scheduling Virtual Grids: The Magrathea System

    Publication Year: 2007 , Page(s): 1 - 7
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    Contemporary production grids do not usually offer the flexibility users are looking for. While different user communities have often contradictory requirements on the operating system, libraries, and applications, the production Grids provide only one rigid environment. This rigidness can be overcome by virtualization, when every user community or even individual user can be provided with its own instance of a virtual Grid, running optimized and tailored operating system and services. The promise of higher flexibility of virtual Grids is compensated by the increase in scheduling complexity. In this paper, we present the Magrathea system that extends the Grid resource management systems with support for virtual environment. After discussing the design requirements, we introduce the Magrathea architecture that consists of three components: the master and slave processes running on virtualized resources and the cache process to provide the information about virtual machine state to the scheduler. Two virtual machines sharing one physical resource and used exclusively, preemption of a lower priority job running in a virtual machine, support for more than two concurrently domains and support for "frozen" services that are repeatedly invoked and suspended are the use scenarios discussed in the second part of the paper. We demonstrate how they are supported by the Magrathea system and what modifications to the Grid resource management system are necessary. The Magrathea is currently in the pre-production use on the Czech national Grid environment META Center. View full abstract»

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  • The Efficacy of Live Virtual Machine Migrations Over the Internet

    Publication Year: 2007 , Page(s): 1 - 7
    Cited by:  Papers (11)  |  Patents (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (283 KB) |  | HTML iconHTML  

    This paper describes a technique to enable live migration of virtual machines over the Internet. The method assumes the network supports Mobile IPv6 and that participating host devices support Xen 3.1. Unlike live migration schemes proposed by other researchers, virtual networks are not required. We describe our work in progress on developing a system that utilizes Mobile IPv6 to enable constant network connectivity through the migration. We identify the sources of delay associated with the live migration and conclude that as long as migrations occur relatively infrequently, live migration over the Internet is practical. View full abstract»

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  • Agility in Virtualized Utility Computing

    Publication Year: 2007 , Page(s): 1 - 8
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (404 KB) |  | HTML iconHTML  

    Virtual machines have emerged as an attractive approach for utility computing platforms because applications running on VMs are fault- and security- isolated from each other, yet can share physical machines. An important property of a virtualized utility computing platform is how quickly it can react to changing demand. We refer to the capability of a utility computing platform to quickly reassign resources as the agility of the platform. We are targeting hosting utility provider environments where the entire platform is under the control of a single administrative domain and application instances often form application-level clusters. In this work, we examine resource reassignment mechanisms in these environments from the agility perspective and outline a new mechanism that exploits properties of a virtualized utility computing platform. This new mechanism employs ghost virtual machines (VMs), which participate in application clusters, but do not handle client requests until activated by the resource management system. We evaluate this, as well as other, mechanisms on a utility computing testbed. The results show that this ghost VM approach is superior to other approaches in its agility, and allows a new VM to be added to an existing application cluster in a few seconds with negligible overhead. This is a promising result as we develop resource management algorithms for a globally distributed utility computing platform. View full abstract»

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