Alexandra M. Carvalho

Research interests | Publications | Software | System administration | Short CV | Personal

How to use the grid

Set your environment

Log into one of the machines where Globus is set-up and, depending on which shell you use, type:

Alternatively, you can include these lines in .cshrc or .bashrc, respectively.

Acquire a certificate

The use of ALGOS grid comprises the acquisition of a user certificate. To request a user certificate, simply run:

Make sure you are running as your normal user account, not root. The grid-cert-request command will ask for a password to protect your key. When you run the grid-cert-request three files will be generated in your ~/.globus directory. One is the request that you need to send to the CA, named usercert_request.pem. Another is the key that corresponds to that request, named userkey.pem. The last is the usercert.pem, which will be a 0 byte file. This is not your certificate, it is merely a placeholder that helps to remind you where to put your certificate when the CA responds to your request.

Address an e-mail to , the CA administrator, and include your file ~/.globus/usercert_request.pem as an attachment. As soon as possible, your certificate will be mailed to you. When it arrives, save the attached file in your ~/.globus directory.

In the end, you should have a userkey.pem and a usercert.pem in your ~/.globus directory. Verify that these files have the following permissions:

Test the grid

In first place, run:

entering the pass phrase when asked. The proxy default expiration is 12 hours, but grid-proxy-init can also take arguments to specify the expiration:

Next, test whether Globus is running on the host:

You are now able to run any command using Globus only by typing:

In order to run MPI-based jobs over Globus run:

The -o switch orders the output to be produced to standard out. The -f switch indicates the name of the .rsl script which should be used to run the MPI-based job.

An example

In order to test the 'ring' example, which is a program that propagates a message among all grid machines, follow these steps:

The output should be as in the ringout.txt file.

Grid shutdown

In order to shutdown the grid, run:

Related links

Research interests | Publications | Software | System administration | Short CV | Personal