Interface of The Grid to The Fabric Rich

Interface of “The Grid” to “The Fabric” Rich Baker Brookhaven National Lab

Outline TOverview & Definitions TFabric vs. Middleware? TFabric vs. Grid? TRefocus the Debate? CHEP 03, California October 16, 2002 2

What are Middleware & Fabric? Applications High Level Grid Services Expose Abstract Services Middleware View (Multiple Implementations of) Concrete Services Gray Area? Fabric Administrative Domain – Security and Site Policy Operating Systems, Batch Queues, File Systems Physical Storage, CPU, Network, etc. CHEP 03, California October 16, 2002 3

Why Is There “Gray Area? ” T Multiple Layers of Fabric q Chip Set, Physical Disks, Raw Hardware q Operating Systems, File Systems q Batch Queues q Site Administration Tools q Policy, Security T Multiple Layers of Middleware q Low Level Services Used by Higher Level Services q Some Push to Reimplement Fabric Services With Grid Aware Services – Is This Still Middleware? q How Low Can (Should) It Go? CHEP 03, California October 16, 2002 4

Can We Draw a Line Between Fabric and Middleware? T What is the Difference Between a High Level Fabric Service and a Low Level Middleware Service? q Site Boundary? But – Many Traditional Fabric Elements Cross Site Boundaries and Many Important Middleware Components Do Not q Maybe Everything is Middleware? Even an Operating System “Translates Concrete Services to Abstract Services” T “The Fabric” Cannot be Separated From Middleware q Not a Useful Distinction CHEP 03, California October 16, 2002 5

Can We Draw a Line Between Fabric and “The Grid? ” T The Fabric is Part of the Grid T Site Boundary? q Many “Pure Grid” Components Reach Inside Sites T Grid Awareness? q Grid Aware “Batch Queues” or “File Systems” May Coexist With Non -Grid Implementations q Even Operating Systems Will Be Grid Aware CHEP 03, California October 16, 2002 6

Refocus the Debate? T Focus on Standard Interfaces/Protocols Between Layers? q Good Middleware Should Provide an Abstract Service With Defined Interfaces Without Dictating Specific Lower Level Concrete Implementations q Good Middleware Should Adapt to Multiple Lower Level Protocols T Focus on Who is Responsible for What? q Site Administrators Have Specific Contractual (or Legal) Obligations q Policy Enforcement and Security are Fundamental Site Functions q Site Administrators Should Have Choices in Implementation CHEP 03, California October 16, 2002 7

Grid / Fabric Interface T Define Interfaces Sites Must Provide q Interfaces, Not Implementations q Must be Consistent with Site Policies T Grid Projects Must Help Develop Implementations q Middleware that Provides Defined Interfaces On Top of Legacy Site Implementations q When Appropriate, Reimplement Legacy Components T Develop Grid Security Model Consistent With Site Policies q Will Require Some Compromises by Sites q Must Be Flexible Enough to Accommodate Variety T Heterogeneity Must Be Expected!!! CHEP 03, California October 16, 2002 8