Note Interne CCR 2011
CCR-41/2011/P: Interventi su Kernel e Microcode per adeguare il processore AMD 8356 Rev. B2 all'ambiente GRID
Nel periodo 2009-2010 la Sezione di Pisa ha installato e messo in produzione un cluster da 1024 core composto dal 128 server bi-processori equipaggiati con CPU AMD Opteron 8356 rev. B2, quad core. Subito dopo l'avvio del cluster (sotto GRID) sono stati riscontrati problemi di prestazioni legati al processore. Il presente lavoro descrive la situazione registrata e gli interventi apportati al Kernel Linux ed al Microcode per ovviare al problema.
CCR-42/2011/P: SSH authentication using GRID credentials
SSH is one of the most widely used tools in Unix. Apart from opening remote shells, its most intriguing feature is the capability to tunnel TCP connections, providing for both a secure channel and an authentication mechanism for generic services lacking them. We will show how to setup a very simple infrastructure that temporarily authorizes users presenting valid X.509 credentials, and in particular Grid users, to use SSH by performing the authentication through HTTPS beforehand. We will also compare this method with tools that provide similar functionalities, such as GSI-Enabled OpenSSH. Finally, a brief description of PROOF on Demand for the LHC ALICE experiment is presented as a use case.