Creating and running an application on the NGS Mike Mineter

2 Policy for re-use This presentation can be re-used for academic purposes. However if you do so then please let training- know. We need to gather statistics of re-use: no. of events, number of people trained. Thank you!!training-

3 Acknowledgements This presentation re-uses material –on globus commands from Stephen Pickering (University of Leeds)

4 Outline A “User interface” machine and our set-up today Commands to be used Practical: –Port code and data from desktop/UI to the NGS compute nodes –Compile and run code –Invoke your application from the UI machine Summary

5 Goals You’ve got your proxy on a UI machine and want to know how to port and run an application Er.. What’s a UI machine?

6 The “UI” machine The users interface to the grid –Where you upload your certificate for your session –Where you create proxy certificates –Where you can run the various commands, including…

7 Globus Tools Globus Toolkit version 2 –GT from VDT 1.2 –(VDT comprises several middleware packages used in EU, US and UK grids) Job submission (GRAM) File transfer (GridFTP) Shell (GSI-SSH) Information Services (MDS/GIIS/GRIS) –Information providers from GLUE schema

8 Our setup Core NGS nodes ssh UI Internet Tutorial room machines grid-data.rl.ac.uk

9 Secure file copy UINGS compute node gsiscp: copies file using proxy certificate to allow AA Code and data

10 Open shell on NGS CN UINGS compute node gsissh Can be an X- windows client Code and data Compile, edit, recompile, build SHORT interactive runs are ok (sequential) Totalview debugger.

11 Establishing contact Connecting to the NGS compute node gsissh via port 2222 Modify environment on the NGS account (note which node you use and keep using it, or repeat commands on other nodes) –.bashrc Used when you connect with gsissh Used by globus

12 gsissh -X -p 2222 grid-compute.leeds.ac.uk -X: enables forwarding of X11 connections -p: sets port through which gsissh works [ can set –X –p 2222 as defaults in config files]

13 Run jobs from the UI UINGS compute node globus_job_run Or globus_job_submit / globus_get_output Code and data Executables Can pass files with these commands: e,g, parameters for a job.

14 PRACTICAL 2

15 The “UI” machine The users interface to the grid –Where you upload your certificate for your session –Where you create proxy certificates –Where you can run the various commands That was the good news. The bad news: install your own (currently!) –May be your desktop with additional software (GT2) – if you run UNIX derivative

16 A multi-VO Grid User Interface Grid services User Interface

17 globus_job_run Forks process to run command. Globus gatekeeper Job request Info system gridmapfile I.S. Job runs on head-node the gatekeeper reads the gridmapfile to map the user’s id from their proxy certificate to a local account head-node

18 globus_job_submit Job queue: PBSPro Globus gatekeeper Job request Info system gridmapfile I.S. Job runs on a cluster node the gatekeeper reads the gridmapfile to map the user’s id from their proxy certificate to a local account head-node

19 Questions -1 “How do I know which compute node to use?” –Use the Information Service –You should find that the Core nodes of the NGS all run the same software –In general you are likely to use the same machine Is my NGS Compute Node account shared across all machines?? –NO – You must synchronise your accounts on different machines yourself. Your account names may be different on each machine. Use GridFTP (from portal) or gsi-scp –You can hold files in the SRB,(Storage Resource Broker –see tomorrow) and read/write these from any compute node

20 Questions -2 “Should I stage an executable?” (stage = Send it to a compute node from my desktop/UI) –Only if the UI produces a binary-compatible file! –Safer to Check it compiles locally Copy to a compute node Compile it there

21 Further information VDT documentation NGS user pages