Practical Implementation of the Virtual Organization Cluster Model

Virtualization has great potential in the realm of scientific computing because of its inherent advantages with regard to environment customization and isolation. Virtualization technology is not without it\u27s downsides, most notably, increased computational overhead. This thesis introduces the operating mechanisms of grid technologies in general, and the Open Science Grid in particular, including a discussion of general organization and specific software implementation. A model for utilization of virtualization resources with separate administrative domains for the virtual machines (VMs) and the physical resources is then presented. Two well-known virtual machine monitors, Xen and the Kernel-based Virtual Machine (KVM), are introduced and a performance analysis conducted. The High-Performance Computing Challenge (HPCC) benchmark suite is used in conjunction with independent High-Performance Linpack (HPL) trials in order to analyze specific performance issues. Xen was found to introduce much lower performance overhead than KVM, however, KVM retains advantages with regard to ease of deployment, both of the VMM itself and of the VM images. KVM\u27s snapshot mode is of special interest, as it allows multiple VMs to be instantiated from a single image located on a network store. With virtualization overhead shown to be acceptable for high-throughput computing tasks, the Virtual Organization Cluster (VOC) Model was implemented as a prototype. Dynamic scaling and multi-site scheduling extensions were also successfully implemented using this prototype. It is also shown that traditional overlay networks have scaling issues and that a new approach to wide-area scheduling is needed. The use of XMPP messaging and the Google App Engine service to implement a virtual machine monitoring system is presented. Detailed discussions of the relevant sections of the XMPP protocol and libraries are presented. XMPP is found to be a good choice for sending status information due to its inherent advantages in a bandwidth-limited NAT environment. Thus, it is concluded that the VOC Model is a practical way to implement virtualization of high-throughput computing tasks. Smaller VOCs may take advantage of traditional overlay networks whereas larger VOCs need an alternative approach to scheduling

Virtual Organization Clusters: Self-Provisioned Clouds on the Grid

Virtual Organization Clusters (VOCs) provide a novel architecture for overlaying dedicated cluster systems on existing grid infrastructures. VOCs provide customized, homogeneous execution environments on a per-Virtual Organization basis, without the cost of physical cluster construction or the overhead of per-job containers. Administrative access and overlay network capabilities are granted to Virtual Organizations (VOs) that choose to implement VOC technology, while the system remains completely transparent to end users and non-participating VOs. Unlike alternative systems that require explicit leases, VOCs are autonomically self-provisioned according to configurable usage policies. As a grid computing architecture, VOCs are designed to be technology agnostic and are implementable by any combination of software and services that follows the Virtual Organization Cluster Model. As demonstrated through simulation testing and evaluation of an implemented prototype, VOCs are a viable mechanism for increasing end-user job compatibility on grid sites. On existing production grids, where jobs are frequently submitted to a small subset of sites and thus experience high queuing delays relative to average job length, the grid-wide addition of VOCs does not adversely affect mean job sojourn time. By load-balancing jobs among grid sites, VOCs can reduce the total amount of queuing on a grid to a level sufficient to counteract the performance overhead introduced by virtualization

Definición de un modelo genérico para la caracterización de escenarios virtuales de redes IP

Tesis doctoral inédita. Universidad Autónoma de Madrid, Escuela Politécnica Superior, junio de 201