Improving quality of service in grids through meta-scheduling in advance
- Autores: Luis Tomás Bolívar
- Directores de la Tesis: Carmen Carrión Espinosa (dir. tes.), María Blanca Caminero Herráez (dir. tes.)
- Lectura: En la Universidad de Castilla-La Mancha ( España ) en 2012
- Idioma: inglés
- Tribunal Calificador de la Tesis: Francisco José Quiles Flor (presid.), Enrique Arias (secret.), Eduardo Huedo Cuesta (voc.), Ignacio Martín Llorente (voc.), Per Östberg (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TESEO
- Resumen
Grids allow the coordinated use of heterogeneous computing resources within large-scale parallel applications in science, engineering and commerce. Since organizations sharing their resources in such a context still keep their independence and autonomy, Grids are highly variable systems in which resources may join/leave the system at any time. This variability makes Quality of Service (QoS) highly desirable, though often very difficult to achieve in practice. One reason for this limitation is the lack of a central entity that orchestrates the entire system, such as the network that connects the various components of a Grid system. Thus, without resource reservations any guarantee on QoS is often hard to achieve. However, in a real Grid system, reservations may not be always feasible, as not all the Local Resource Management Systems permit them. There are also other types of resources, such as network, which may lack a global management entity, thereby making their reservation impossible. Because of that, the provision of QoS in Grids needs attention from the research community.
One way of contributing to the provision of QoS in Grids is by performing meta-scheduling of jobs in advance, which means that jobs are scheduled some time before they are actually executed. In this way, it becomes more likely that the appropriate resources are available to run the jobs when needed, so that QoS requirements of jobs are met.
The main aim of this Thesis is to develop a system capable of managing QoS in real Grid environments. To this end, this Thesis investigates the QoS provision to Grid users by means of efficient meta-scheduling. New scheduling metrics have been added to a current Grid meta-scheduler and a Grid meta-scheduling layer, named SA-Layer, has been developed. The SA-Layer provides the meta-scheduling in advance functionality in a real Grid environment, making possible to deal with users' QoS requirements.
This software has been developed in an incremental way. Thus, different modules have been added and modified to increase and improve the functionality of this layer. Initially, the implementation of red-black trees as an efficient data structure to manage resource usage information was tackled. Subsequently, different prediction techniques were developed to make a proper scheduling by performing accurate estimations about status of resources and job durations on them. After that, two rescheduling techniques (preventive and reactive techniques) were implemented to deal with low resource usage due to the fragmentation generated at the allocation process and owing to unfavorable previous decisions. Finally, the integration of the SA-Layer and a job prioritization system, named FSGrid, is addressed. This system provides SA-Layer with the information needed to take into account different usage policies for users, projects and virtual organizations. In this way, different QoS levels may be provided depending on the established policies.
Those proposals, as well as their evaluation into a real Grid environment based on the Globus Toolkit and the GridWay meta-scheduler, have been developed and their performance has been evaluated. To this end, a testbed where experiments are carried out has been built up by using non-dedicated machines across several administrative domains.
