This page refers to the gLite version of CREAM. For CREAM released with EMI, please refer to the new CREAM wiki:

Besides the input/output sandbox files (see here) there are some other files to be considered:

  • The CREAM jobWrapper and the user proxies, that are staged from the CE node to the WN where the job will run
  • The standard output and error files of the Cream jobWrapper, that are copied from the WN to the CE when the job completes its execution.

To enable these file transfers, when Torque is used as batch system, there are 2 possible options:

  • Configure the ssh trust between CE and WNs.
This is what is done by default when configuring via yaim
  • Share the CREAM sandbox area through NFS and configure $usecp accordingly in pbs_mom configuration.
In more detail:
  • Mount the /opt/glite/var/cream_sandbox also in the WNs. Let's assume that in the WNs this directory is mounted as /cream_sandbox)
  • On the WNs, add the following to the Torque client config file (generally /var/spool/pbs/mom_priv/config):
$usecp <CE node>:/opt/glite/var/cream_sandbox /cream_sandbox
This $usecp line means that every time Torque will have to copy a file from/to <CE node>:/opt/glite/var/cream_sandbox (which is the case during the stage in/stage out phase), it will have to use a cp from /cream_sandbox instead.

Please also note (not only for Torque):

  • If you want to have several (CREAM) CEs sharing the same WNs, you need to mount each CE sandbox area to a different mount point on the WN, such as /cream_sandbox/ce_hostname. For Torque you will have to adjust the $usecp line for each CE accordingly.
  • The CREAM sandbox directory name (default /opt/glite/var/cream_sandbox) can be changed using the yaim variable CREAM_SANDBOX_DIR

in the CREAM configuration file (/opt/glite/etc/glite-ce-cream/cream-config.xml)

Thanks to Michel Jouvin for having provided this information