Self-configuring virtual networks rely on structured P2P routing to provide seamless connectivity among nodes through overlay routing of virtual IP packets, support decentralized hole-punching to establish bi-directional communication links among nodes behind network address translators, and dynamic configuration of virtual IP addresses. Our experiences with deployments of virtual networks in support of wide-area overlays of virtual workstations (WOWs) reveal that connectivity constraints imposed by symmetric NATs and by Internet route outages often hinder P2P overlay structure maintenance and routability, subsequently limiting the ability of WOWs to deliver high-throughput computing through aggregation of resources in different domains.

Deploying a modern software service usually involves installing several software components, and configuring these components properly to realize the complex interdependencies between them. This process, which accounts for a significant portion of information technology (IT) cost, is complex and error-prone. In this paper, we propose delta configuration - an approach that reduces the cost of software deployment by eliminating a large number of choices on parameter values that administrators have to make during deployment. In delta configuration, the complex software stack of a distributed service is first installed and tested in a test environment. The resulting software images are then captured and used for deployment in production environments. To deploy a software service, we only need to copy these pre-configured software images into a production environment and modify them to account for the difference between the test environment and a production environment. We have implemented a prototype system that achieves software deployment using delta configuration of the configuration state captured inside virtual machines. We perform a case study to demonstrate that our scheme leads to substantial reduction in complexity for the customer, over the traditional software deployment method.

Wide-area overlays of virtual workstations (WOWs) have been shown to provide excellent infrastructure for deploying high throughput computing environments on commodity desktop machines by (1) offering scalability to a large number of nodes, (2) facilitating addition of new nodes even if they are behind NATs/firewalls and (3) supporting unmodified applications and middleware. However, deployment of WOWs from scratch still requires setting up a bootstrapping network and managing centralized DHCP servers for IP address management. In this paper we describe novel techniques that allow multiple users to create independent, isolated virtual IP namespaces for their WOWs without requiring a dedicated bootstrapping infrastructure, and to provision dynamic host configuration (e.g. IP addresses) to unmodified DHCP clients without requiring the setup and management of a central DHCP server. We give qualitative and quantitative arguments to establish the feasibility of our approach.

This paper describes WOW, a distributed system that combines virtual machine, overlay networking and peer-to-peer techniques to create scalable wide-area networks of virtual workstations for high-throughput computing. The system is architected to: facilitate the addition of nodes to a pool of resources through the use of system virtual machines (VMs) and self-organizing virtual network links; to maintain IP connectivity even if VMs migrate across network domains; and to present to end-users and applications an environment that is functionally identical to a local-area network or cluster of workstations. We describe a novel, extensible user-level decentralized technique to discover, establish and maintain overlay links to tunnel IP packets over different transports (including UDP and TCP) and across firewalls. We also report on several experiments conducted on a testbed WOW deployment with 118 P2P router nodes over PlanetLab and 33 VMware-based VM nodes distributed across six firewalled domains. Experiments show that the latency in joining a WOW network is of the order of seconds: in a set of 300 trials, 90% of the nodes self-configured P2P routes within 10 seconds, and more than 99% established direct connections to other nodes within 200 seconds. Experiments also show that the testbed delivers good performance for two unmodified, representative benchmarks drawn from the life-sciences domain. The testbed WOW achieves an overall throughput of 53 jobs/minute for PBS-scheduled executions of the MEME application (with average single-job sequential running time of 24.1s) and a parallel speedup of 13.5 for the PVM-based fastDNAml application. Experiments also demonstrate that the system is capable of seamlessly maintaining connectivity at the virtual IP layer for typical client/server applications (NFS, SSH, PBS) when VMs migrate across a WAN

Peer-to-peer (P2P) networks have mostly focused on task oriented networking, where networks are constructed for single applications, i.e. file-sharing, DNS caching, etc. In this work, we introduce IPOP, a system for creating virtual IP networks on top of a P2P overlay. IPOP enables seamless access to grid resources spanning multiple domains by aggregating them into a virtual IP network that is completely isolated from the physical network. The virtual IP network provided by IPOP supports deployment of existing IP-based protocols over a robust, self-configuring P2P overlay. We present implementation details as well as experimental measurement results taken from LAN, WAN, and Planet-Lab tests

This poster describes current work on the application of network virtualization and peer-to-peer routing techniques that overlay IP traffic and provide seamless connectivity to virtual machines in grid computing. Such IP-over-P2P virtual network - IPOP - is an overlay network that uses a virtual IP address space and allows nodes that belong to a grid to be seamlessly pooled together. The overlay network is self-configured as nodes join/leave the virtualized grid, and IP-level bi-directional connectivity among peers is provided. The decoupling provided by the overlay enables grid applications to leverage a wealth of IP-based software typically available in local-area environments. Such virtual networks, when combined to complementary resource virtualization techniques provided by O/S virtual machines [Xen, Rarham et al. (2003), VMware, Sugerman et al., (2001), User Mode Linux, Dike, J. (2000)], provide a scalable framework for dealing with a fundamental goal of grid computing: sharing resources in a secure and flexible manner by Figueiredo, Dinda and Fortes (2003)

Virtual machines provide flexible, powerful execution environments for Grid computing, offering isolation and security mechanisms complementary to operating systems, customization and encapsulation of entire application environments, and support for legacy applications. This paper describes a Grid service — VMPlant — that provides for automated configuration and creation of flexible VMs that, once configured to meet application needs, can then subsequently be copied ("cloned") and dynamically instantiated to provide homogeneous execution environments across distributed Grid resources. In combination with complementary middleware for user, data and resource management, the functionality enabled by VMPlant allows for problem-solving environments to deliver Grid applications to users with unprecedented flexibility. VMPlant supports a graph-based model for the definition of customized VM configuration actions; partial graph matching, VM state storage and "cloning" for efficient creation. This paper presents the VMPlant architecture, describes a prototype implementation of the service, and presents an analysis of its performance.