(r5) LHCComputingGrid < CMS

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*Getting access to LHC Computing Grid.* One can find a brief introductory material at the [[http://www.grid.kfki.hu/?lcg&gettingstarted][RMKI's getting started page]], where you can find information on how to get access to LCG. There are also simple examples on that page.

*Some more practical information on running a typical job.*

   * Get authenticated on the LCG:

=> grid-proxy-init=        Here, you will be prompted for your grid password. Or:

=> grid-proxy-init -valid 4:00=        This is the same, but the authentication will be only valid for 4 hours.

Now you can perform various operations on the grid, e.g. send jobs. You can get info on your authentication (e.g. expiration etc.) by =grid-proxy-info=. You can destroy your authentication proxy by =grid-proxy-destroy=.

   * Get your jobs authenticated on the LCG:

=> myproxy-init=        Here, you will be prompted for your grid password, and to specify a password attached to your so called _job proxy_ to be created. Or:

=> myproxy-init -n=        Here, you won't be asked to specify a password for your proxy.

Running =myproxy-init= is necessary when you are running long-term jobs. In this case, the =myproxy-init= ensures that your jobs still will have authentication even after your interactive proxy (obtained by =grid-proxy-init=) has expired. You can get information on your job proxy by =myproxy-info=. You can destroy your job proxy by =myproxy-destroy=. Note: if you don't use this, you may not be able to retrieve your job outputs for long-term jobs!

   * Running a job:

A "Hello World!" example can be found at [[http://www.grid.kfki.hu/?lcg&gettingstarted][RMKI's getting started page]]. Instead of a "Hello World!" example, we present here a framework, with which one can send jobs in mass to the LCG: see the attached tarball called 'submit.tar'. You can adjust these shell script wrappers to your needs. This assumes that your jobs are placed in a directory scheme like in the attached example 'skeleton.tar'. This latter is a framework for simple jobs, which are ran on a simple computers (contains an automated Makefile and an automated starter shell script).

   * Specifying system requiremets:

It is a common task to require some software environment from the working nodes, where your jobs will be executed (e.g. AFS). You can specify requirements by placing lines like the following line to your .jdl file:

=Requirements = (Member("AFS", other.GlueHostApplicationSoftwareRunTimeEnvironment));=

One can apply logical operations to the arguments, like:

=Requirements = (Member("AFS", other.GlueHostApplicationSoftwareRunTimeEnvironment) && Member("VO-cms-ORCA_8_13_1", other.GlueHostApplicationSoftwareRunTimeEnvironment));=

-- Main.AndrasLaszlo - 03 Mar 2006

Topic revision: r5 - 2006-03-03 - AndrasLaszlo

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