1. Andrew McNabSlashGrid/GFS BOF, GGF9, 7 Oct 2003Slide 1 SlashGrid = “/grid” Andrew McNab High Energy Physics University of Manchester http://www.gridpp.ac.uk/authz/

2. Andrew McNabSlashGrid/GFS BOF, GGF9, 7 Oct 2003Slide 2 SlashGrid motivation Produced as part of EU DataGrid EDG uses Unix pool accounts for job execution –user assigned to a temporary account for duration of the job, normal Unix permissions apply –but all files created need to be deleted before pool account can be created SlashGrid gets round this by controlling access to files by Grid credential rather than Unix ID –so SlashGrid primarily motivated by local security

3. Andrew McNabSlashGrid/GFS BOF, GGF9, 7 Oct 2003Slide 3 SlashGrid implementation Currently Linux-specific –uses Linux venus/coda kernel module to connect a client-side daemon to OS –replacing this with nfs daemon->OS connector Daemon handles the virtual filesystems, does credential checking and network operations. SlashGrid best described as a “Framework for Grid-aware filesystems” –provides verifying/storage of Grid credentials –multiple filesystem types, each supported by a loadable.so module

4. Andrew McNabSlashGrid/GFS BOF, GGF9, 7 Oct 2003Slide 4 Some plugin/filesystem types certfs - a robust demonstration fs –local disk storage controlled by GACL access control policies, and X509, GSI or VOMS cred. curlfs - an example networked fs –remote access to HTTP(S) servers –presents local credentials (eg GSI proxy) to remote services when auth required gmapfs - an example “utility” fs –populated with virtual symbolic links to augment pool account system

5. Andrew McNabSlashGrid/GFS BOF, GGF9, 7 Oct 2003Slide 5 What SlashGrid is not Not a “Grid” filesystem –it’s deliberately protocol-neutral –it’s a framework for building filesystems on Not a monolithic system –it lets third parties write plugins for their favourite file transfer protocol –third parties may need “utility” filesystems that we can’t anticipate (cf Linux /proc) Not a complete fs security model –it supports one (GSI/VOMS/GACL), but can readily support others (eg Kerberos based)

6. Andrew McNabSlashGrid/GFS BOF, GGF9, 7 Oct 2003Slide 6 Summary Motivated by local security Work done in a client-side daemon rather than kernel Daemon supports third-party plugins Aim for network-protocol and security-model neutrality Should be seen as a client for “Grid File Systems” rather than as “A Grid File System” itself.