http://www.grid-support.ac.uk
http://www.ngs.ac.uk
Creating and running an
application on the NGS
Mike Mineter
mjm@nesc.ac.uk
http://www.nesc.ac.uk/
http://www.pparc.ac.uk/
http://www.eu-egee.org/
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
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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?
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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…
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Globus Tools
• Globus Toolkit version 2
– GT 2.4.3 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
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Our setup
Tutorial room
machines
ssh
UI
Internet
Core NGS nodes
grid-data.rl.ac.uk
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Secure file copy
UI
NGS compute node
Code and data
gsiscp: copies file
using proxy
certificate to allow
AA
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Open shell on NGS CN
UI
NGS compute node
Code and data
gsissh
Can be an Xwindows client
Code and data
Compile, edit, recompile,
build
SHORT interactive runs
are ok (sequential)
Totalview debugger.
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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
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• 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]
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Run jobs from the UI
UI
NGS compute node
Code and data
Code and data
Executables
globus_job_run
Or
globus_job_submit /
globus_get_output
Can pass files with
these commands: e,g,
parameters for a job.
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PRACTICAL 2
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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
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A multi-VO Grid
User
Interface
User
Interface
Grid services
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globus_job_run
Job request
the gatekeeper
reads the
gridmapfile to
map the user’s
id from their
proxy
certificate to a
local account
head-node
Globus gatekeeper
I.S.
Info
system
gridmapfile
Forks process to run command.
Job runs on
head-node
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globus_job_submit
Job request
the gatekeeper
reads the
gridmapfile to
map the user’s
id from their
proxy
certificate to a
local account
head-node
Globus gatekeeper
I.S.
Info
system
gridmapfile
Job queue: PBSPro
Job runs on a
cluster node
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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
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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
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Further information
• VDT documentation
http://www.cs.wisc.edu/vdt/documentation.html
• NGS user pages
http://www.ngs.ac.uk/users/userguide.html
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