GriT: A CORBA-based Grid Middleware Architecture

1. GriT: A CORBA-based Grid Middleware Architecture • Presented by Dr. Jeff Gray • Aniruddha Gokhale, Balachandran Natarajan • {gokhale, bala}@isis-server.isis.vanderbilt.edu • ISIS, Vanderbilt University • www.isis.vanderbilt.edu/~gokhale/PDF/HICSS-GRID03.pdf HICSS 03

2. Motivation Grid Application Characteristics • Multiple end-to-end QoS properties • CPU and data intensive (petaflops, petabytes) • Secure, controlled access to resources from multiple service providers => need individual SLAs • E.g., collaborative scientific applications, virtual surgery HICSS 03

3. Grid Application Development Challenges Standards-based programmable middleware enhanced with Web API 1. Tight coupling with COTS grid infrastructure middleware (GIMs) 2. Proliferation of GIMs, such as Globus, ICENI, Legion 3. Need to satisfy simultaneous multiple QoS 4. No single sign-on secure access capability to resources 5. Accidental complexities assembling and deploying grid applns 6. Lack of resource reservation & QoS provisioning patterns HICSS 03

4. Grid TAO (GriT) Architecture • Based on principles from DP-CORBA, RT-CORBA, CCM • Seamless integration with GIMs via extensible transport capabilities • Uses web-based interfaces for service provisioning • Implemented using TAO and CIAO technology HICSS 03

5. Grid Service Provider (GSP) • Web service access to underlying middleware (e.g., OGSA) • Single sign-on capabilities • GSP maintains individual SLAs on behalf of user • Collaborations via session initiation protocol (SIP) HICSS 03

6. Meta-Resource Broker (MRB) • Broker for resources from underlying service providers • Maintains abstractions of concrete resources • Uses DP-CORBA parallel and part objects for parallel resource reservation HICSS 03

7. MRB Part Object Core • Uses TAO’s pluggable protocol framework to talk Grid protocols • Used for resource discovery and reservation HICSS 03

8. Avoiding Starvation of Transient Applns • Context – peer-to-peer collaborative applns will require resources for short durations • Problem – persistent long duration applications might starve short duration applications • Solution – GriT uses “slack stealing” algorithms by diverting resources from persistent applications to short duration applications during periods of non-use but returns them to persistent applns whenever required. HICSS 03

9. Transparent Dispatching of Requests • Context – Incoming appln request to MRB is received by the virtual object representing collection of reserved resources • Problem – Incoming requests to MRB must be transparently fanned out to all the required resources • Solution – GriT enhances the Portable Object Adapter to maintain actual address of the resources so that incoming requests are transparently forwarded to desired resource. HICSS 03

10. Ensuring Dependability • Context – Dependability is key QoS requirement for Grid applications • Problem – The collection of resources maintained by the MRB must now be a collection of redundant resources that needs a policy to determine the order in which these resources are used and minimizing overprovisioning • Solution – GriT employs TAO’s pluggable load balancing service that allows service providers to insert custom strategies for minimizing overprovisioning HICSS 03

11. Interacting with Grid Protocols • Context – Grid protocols such as Globus are typically categorized into 4 layers • Problem – There is no standardization yet on how the underlying grid protocols are structured. Existing applns are tightly coupled to these protocols. • Solution – GriT uses TAO’s pluggable transport bridge solution to hook up to any underlying transport. HICSS 03

12. Simplifying use of GriT • Context – Both wireless and wireline clients need to participate in collaborative grid applns requiring a thin client solution • Problem – Programming at the GriT level might also tightly couple the client with GriT API while also increase footprint • Solution – GriT services are made available as a web service. This approach is in tune with the emerging Open Grid Services Architecture approach HICSS 03

13. Summary of Ongoing Work • FT and RT capabilities in TAO done • DP-CORBA implementation on going • CIAO CCM implementation at Washington Univ DOC • Using model integrated computing to automate provisioning tasks • Testing to be done using Vanderbilt’s Vampire cluster and Utah’s Emulab www.isis.vanderbilt.edu HICSS 03

14. Concluding Remarks • GriT enhances TAO/CIAO • Meta resource broker • Patterns for resource reservation and QoS adaptation • Uses Model Integrated Computing tools • GriT will be available at www.isis.vanderbilt.edu HICSS 03