LCG/GD Proposal

For the beginning (till the end of 2003) we suggest the following way to distribute the experiments software.We point out where we have to do some development.
Sites can choose between providing space in a shared file system for the VOs or having no shared file system available.
This is communicated to the jobs by the local environment variable VO_$<$EXP$>$_SW_DIR.The variable VO_$<$EXP$>$_SW_DIR is set to "." in case no shared file-system is available. In case there is a shared file system the path to it is published (for instance: "/opt/ALICE"). The software has to use the environment variable directly. There is no guarantee that the path is the same on all nodes.
Currently in the GLUE schema there is not a CE attribute that allows for the publication of the information relative to the existence of a shared files system for software installation.
We describe the steps that a ESM has to go through to distribute, certify and announce the installation of the experiments software. LCG will provide template scripts that illustrate the procedure. The scripts can be found in Appendix B.

Step 1)
The ESM moves the packed software to a SE on each site where the software is to be installed. The ESM uses the replica manager commands for this.

Step 2)
The ESM directs an installation and certification job to the sites where the software has been copied. Depending on VO_$<$EXP$>$_SW_DIR the job installs the software at the indicate location and runs the certification suite. This results in a report on which the ESM bases the next actions.

Step 3)
For sites on which the installation/certification has been successfully run the ESM adds the tag that indicates the version n the : GlueHostApplicationSoftwareRunTimeEnvironment attribute in the Information System using the GRIS running on the CE. Later we describe how the ESMs can manipulate this entry.