gLite CREAM Computing Element

Functional description

The CREAM (Computing Resource Execution And Management) Service is a simple, lightweight service for job management operation at the Computing Element (CE) level. It replaces the lcg-CE. CREAM accepts job submission requests (which are described with the same JDL language used to describe the jobs submitted to the Workload Management System) and other job management requests (e.g. job cancellation, job monitoring, etc). CREAM can be used by the Workload Management System (WMS), via the ICE service, or by a generic client, e.g. an end-user willing to directly submit jobs to a CREAM CE. For the latter user case a C++ command line interface and Java clients are available. CREAM exposes a web service interface.

Daemons running

Daemons running detailed link

Init scripts and options (start|stop|restart|...)

• /etc/init.d/tomcat5 {start|stop|restart|condrestart|status|version}
• /etc/init.d/globus-gridftp {start|stop|restart|status}
• /etc/init.d/bdii {start|stop|restart|condrestart|status}
• /etc/init.d/mysqld {start|stop|status|condrestart|restart}
• /etc/init.d/gLite {start|stop|restart|status|version}
• /opt/glite/etc/init.d/glite-ce-blparser

• How to stop/suspend the service:
• A site admin can stop the CREAM service just stopping the container:
  • /etc/init.d/tomcat stop

• With the CREAM service it is possible to suspend submission of jobs calling the correct operation with a client (for example glite-ce-disable-submission of the glite-ce-cream-cli package). The user must be registered as a CREAM administrator for doing that (i.e. her DN must be listed in the file /etc/grid-security/admin-list).

• How to start/resume the service:
• A site admin can start the CREAM service just launching the container:
  • /etc/init.d/tomcat start

• It is possible to resume the job submission calling the correct operation with a client (for example glite-ce-enable-submission of the glite-ce-cream-cli package). The user must be registered as a CREAM administrator for doing that (i.e. her DN must be listed in the file /etc/grid-security/admin-list).

Configuration files location with example or template

Configuration files detailed link

Logfile locations (and management) and other useful

Logfile locations detailed link

Open ports

Details about ports: GLiteCREAMCE - Ports

Possible unit test of the service

Submitting jobs directly to CREAM via the CREAM CLI (glite-ce-* commands) or through the WMS.

The CREAM testsuite (described Here) can be used as well

Where is service state held (and can it be rebuilt)

CREAM job related information are kept in the CREAM DB and in the filesystem in the directory referred by CREAM_SANDBOX_DIR (usually /opt/glite/var/cream_sandbox) in the CREAM configuration file (/opt/glite/etc/glite-ce-cream/cream-config.xml).

Cron jobs

Cron jobs detailed link

Security information

• The authZ in CREAM is mainly VOMS-based a site admin can remove a given VO/Role item from the gridmap file.

Access control Mechanism description (authentication & authorization)

Detailed information about Access control Mechanism

How to block/ban a user

How to block/ban an user detailed link

Network Usage

Nothing reported,

Firewall configuration

Nothing reported.

Security recommendations

Security recommendations detailed link

Security incompatibilities

Nothing reported.

List of externals (packages are NOT maintained by Red Hat or by gLite)

Nothing reported.

Other security relevant comments

Security comments detailed link

Utility scripts

For this section, it's possible to use a script which checks some parts of the configuration.

It is available and documented at: link

Location of reference documentation for users

• CREAM CE documentation -- The "User's guides" section

Location of reference documentation for administrators

• CREAM CE documentation -- The "Administrator guides" section