Tolerancia A Fallas Y Alta Disponibilidad En Sistemas Distribuidos PDF Download

Current distributed systems that are capable of sharing resources in a distributed manner are experiencing an increase in their use and scope.This increased use in various application areas is largely due to the low cost of deployment and maintenance of a distributed environment, when compared to architectures like supercomputers. Then, many research efforts today are focused on providing solutions for distributed systems. It is essential that the solutions proposed allow for the sharing of a very large number of resources. This is a complex challenge to tackle since we do not want the solution to degrade as the number of system resources increase. It is also imperative that the solutions proposed, adapt to failures that occur both in the network and in the hardware and / or software that form the distributed system. This does not imply that the components should be universally available, but that the solution should be able to adapt to obtain the highest possible performance from all the components available at a given time. This is a more complex challenge. This thesis proposes a Resource Discovery Service (of services or resources) for large-scale distributed systems that are able to adapt to failures that occur in the system. By large scale systems, we mean systems that may be made up of hundreds, thousands or millions of machines. Failures refer to components that are not accessible through the network, components that are not working, or are overloaded, etc. It should be mentioned that in this work we found that in a real environment of geographically distributed resources, it is essential for service discovery to be fault tolerant. In one of the evaluations of our proposed discovery service, we chose 150 machines distributed geographically throughout Europe at random, without knowing if they were in a state of failure or not. We found that 24'67% of them were unavailable because they were in a failed state or because they failed during the evaluation of our service discovery. In this thesis, the proposed discovery service is based on an overlay that has a hypercube topology that interconnects nodes / intermediaries (brokers). The term overlay is used to describe a virtual network constructed at the application layer, above the level of TCP / IP. It acts as an intermediary component that mediates between service consumers (or clients) and service providers (or servers).