1. LUNARC, Lund UniversityLSCS 2002 Transparent access to finite element applications using grid and web technology J. Lindemann P.A. Wernberg and G. Sandberg LUNARC, Lund University

2. LSCS 2002 Some earlier work —R. Larsson, Encapsulation of a finite element program using a distributed object model, Masters dissertation TVSM-5095, Division of Structural Mechanics, Lund University, 1999 —J. Lindemann, O. Dahlblom, G. Sandberg, An Approach For Distribution Of Resources In Structural Analysis Software, ECCM ’99, Munich, Germany, 1999 —Programming and Visualisation Techniques in Finite element Software, Division of Structural Mechanics, Licentiate Dissertation, TVSM-3050, 2001 —Using CORBA middleware in finite element software, ICCS 2002 —Using CORBA middleware in finite element software, Future Generation Computer Systems, Elsevier, 2002, Accepted for publication

3. LUNARC, Lund UniversityLSCS 2002 Transparent access Creating a easier interface to present clusters Extend user interface with grid services Distributed applications integrating seamlessly with clusters and grids CORBA interfaces to clusters and grids

4. LUNARC, Lund UniversityLSCS 2002 Using clusters Log in –Instructions on how to use SSH –Getting SSH client software if client is MS Windows –Instructions on unix tools mkdir proj sftp/scp user@... –Instructions on how to transfer files vi/joe submit script –Submit script documentation Queue management –qsub script –qstat... Transfer result files back –sftp/scp For many, this is a straightforward process, but why do we get so many questions??

5. LUNARC, Lund UniversityLSCS 2002 Cluster Web Portal Web interface well established interface –Most users know what to do Multiple entrypoints –Novice users (web interface) –Intermediate users (web/cli modification) –Experienced users (web monitoring/cli) Project based –One directory per project –Project includes input files and submission scripts CWP creates submit scripts from job definition stored in database –templates for different application types

6. LUNARC, Lund UniversityLSCS 2002 CWP installed on retired production cluster –Easier to experiment without any users... 8 nodes (legs...) –AMD 1100 Mhz –1 Gb memory –2x15 Gb striped disks –RedHat Linux 7.2 Frontend –AMD 1000 Mhz –256 Mb memory –80 Gb disk –RedHat Linux 7.2 Network –100Mbit Fast Ethernet The Sleipner Test Cluster Lunarc clusters Whenim6465 nodes Husmodern32 nodes Sleipner8 nodes

7. LUNARC, Lund UniversityLSCS 2002 CWP Example

8. LUNARC, Lund UniversityLSCS 2002 CWP

9. LUNARC, Lund UniversityLSCS 2002 CWP

10. LUNARC, Lund UniversityLSCS 2002 CWP

11. LUNARC, Lund UniversityLSCS 2002 CWP

12. LUNARC, Lund UniversityLSCS 2002 CWP

13. LUNARC, Lund UniversityLSCS 2002 CWP

14. LUNARC, Lund UniversityLSCS 2002 CWP

15. LUNARC, Lund UniversityLSCS 2002 CWP

16. LUNARC, Lund UniversityLSCS 2002 CWP

17. LUNARC, Lund UniversityLSCS 2002 CWP

18. LUNARC, Lund UniversityLSCS 2002 CWP

19. LUNARC, Lund UniversityLSCS 2002 CWP

20. LUNARC, Lund UniversityLSCS 2002 CWP

21. LUNARC, Lund UniversityLSCS 2002 CWP

22. LUNARC, Lund UniversityLSCS 2002 CWP

23. LUNARC, Lund UniversityLSCS 2002 CWP

24. LUNARC, Lund UniversityLSCS 2002 CWP

25. LUNARC, Lund UniversityLSCS 2002 CWP

26. LUNARC, Lund UniversityLSCS 2002 CWP

27. LUNARC, Lund UniversityLSCS 2002 CWP Implementation Apache Web Server SSL PHP 4.x OpenPBS OpenSSH –Execution of commands MySQL database –Job descriptions –User accounts (web accounts) –Announcements/news –Too be extended...

28. LUNARC, Lund UniversityLSCS 2002 CWP Future Jobsubmission through Nordugrid –PHP security functions must be implemented Submission of jobs+input files to other clusters without shared filesystems or Nordugrid connection –Packing job and description into a job-package –Users must have account on other cluster More application templates Debugging, documentation and installation scripts

29. LUNARC, Lund UniversityLSCS 2002 Components in software Hardware often consist of components Software components = hardware components. Components in software can be exchanged. –If the interface is the same –Component model / Object model needed CORBA, DCOM, RMI use an intermediate language for describing interfaces –Enabling component design

30. LUNARC, Lund UniversityLSCS 2002 CORBA Object Management Group’s specification for interoperability and interaction between objects and applications. CORBA 1.1 released in 1991. Language neutral. Object oriented. Object interfaces described using the Interface Definition Language, IDL.

31. LUNARC, Lund UniversityLSCS 2002 CORBA concepts and terminology client - entity that invokes a request on a CORBA object. CORBA object - ”virtual” entity capable of being located by an ORB and having client requests invoked on it. server - application in which one or more CORBA objects exist. object reference - handle used to identify, locate and address a CORBA object. servant - programming language entity that implements one or more CORBA objects.

32. LUNARC, Lund UniversityLSCS 2002 Interface Definition language interface Echo { string Shout(in string word); } class Echo : virtual public CORBA::Object { Echo(const Echo&);... public:... char* Shout(const char* word); }; IDL-compiler (C++)

33. LUNARC, Lund UniversityLSCS 2002 Name service CORBA objects acessed by object references –Unique identifier, also contains ip/port information –Must be retrieved somehow –CORBA 2.3 introduced a Name service Provides location transparency –bm/servers/factories/forcepad -> object reference –Name service location provided at startup DNS for CORBA objects

34. LUNARC, Lund UniversityLSCS 2002 Finite element CORBA implementation

35. LUNARC, Lund UniversityLSCS 2002 Finite element CORBA implementation

36. LUNARC, Lund UniversityLSCS 2002 ForcePAD server interface Designed to reduce the number of requests –Object request has a cost determined by latency and marshaling rate Latency the most critical factor –A CORBA request 50-5000 times slower than a function call in C++ Marshaling rate determined by network bandwith

37. LUNARC, Lund UniversityLSCS 2002 ForcePAD interfaces

38. LUNARC, Lund UniversityLSCS 2002 Client/server configuration

39. LUNARC, Lund UniversityLSCS 2002 Client/server configuration

40. LUNARC, Lund UniversityLSCS 2002 Client/server configuration

41. LUNARC, Lund UniversityLSCS 2002 CORBA and FE applications For more information –Programming and Visualisation techniques in Finite Element Software, TVSM-3050 –Using CORBA middleware in finite element software, Future Generation Computer Systems, Elsevier, 2002

42. LUNARC, Lund UniversityLSCS 2002 CORBA in clusters and grids CORBA enabled applications requires a CORBA aware cluster Globus toolkit has CORBA bindings for job submission and resource management –Bindings not very well supported/developed –How do we run CORBA enabled finite element applications using Globus? Initial development of a CORBA enabled cluster has been done –Sleipner will testbed for these efforts

43. LUNARC, Lund UniversityLSCS 2002 CORBA enabled cluster Interface definitions needed (IDL) for –Cluster information system –Resource management –File transfer –Queue management –Job submission –Security Each cluster becomes a set of CORBA objects Simple grid solutions can be created by connecting CORBA enabled clusters Communication over SSL

44. LUNARC, Lund UniversityLSCS 2002 CORBA cluster Queue system

45. LUNARC, Lund UniversityLSCS 2002 Web based engineering tools

46. LUNARC, Lund UniversityLSCS 2002 Web based engineering tools

47. LUNARC, Lund UniversityLSCS 2002 Web based engineering tools

48. LUNARC, Lund UniversityLSCS 2002 Conclusions Broader user base requires –Simple user interface –Smooth learning curve Experienced users benefit a better interface –Monitoring –Simple control Web portal can be central point for grid based resources CORBA based distributed finite element applications can be supported on clusters –CORBA based cluster abstraction –Globus CORBA interface CORBA based applications enable powerful web based engineering tools