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System Administrator Guide for CREAM for EMI-1 release

Installation and Configuration


Operating system

A standard 64 bit SL(C)5 distribution is supposed to be properly installed.

Node synchronization

A general requirement for the Grid nodes is that they are synchronized. This requirement may be fulfilled in several ways. One of the most common one is using the NTP protocol with a time server.

Cron and logrotate

Many components deployed on the CREAM CE rely on the presence of cron (including support for /etc/cron.* directories) and logrotate. You should make sure these utils are available on your system.

Batch system

If you plan to use LSF as batch system for your CREAM CE, you have to install and configure it before installing and configuring the CREAM software. Since LSF is a commercial software it can't be distributed together with the middleware.

Plan how to deploy the CREAM CE

CREAM CE and gLite-cluster

glite-CLUSTER is a node type that can publish information about clusters and subclusters in a site, referenced by any number of compute elements.

glite-CLUSTER can be deployed in the same host of the CREAM-CE or in a different one.

The following deployment model are possible:

  • CREAM-CE can be configured without worrying about the glite-CLUSTER node. This can be useful for small sites who don't want to worry about cluster/subcluster configurations because they have a very simple setup. In this case CREAM-CE will publish a single cluster/subcluster.

  • CREAM-CE can work on cluster mode using the glite-CLUSTER node type. This is done as described below by defining the yaim setting CREAMCE_CLUSTER_MODE=yes. The CREAM-CE can be in the same host or in a different host from the glite-CLUSTER node.

More information about glite-CLUSTER can be found at https://twiki.cern.ch/twiki/bin/view/LCG/CLUSTER


First of all, install the yum-protectbase rpm:

  yum install yum-protectbase.noarch 

Then proceed with the setting of the software repositories


For a successful installation, you will need to configure your package manager to reference a number of repositories (in addition to your OS);

  • the EPEL repository
  • the EMI middleware repository
  • the CA repository

and to REMOVE (!!!) or DEACTIVATE (!!!)

  • the DAG repository

The EPEL repository

You can install the EPEL repository, issuing:

rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm

The EMI middleware repository

The EMI-1 RC3 repository can be found under:


To use yum, the yum repo to be installed in /etc/yum.repos.d can be found at https://twiki.cern.ch/twiki/pub/EMI/EMI-1/rc3.repo

The Certification Authority repository

The most up-to-date version of the list of trusted Certification Authorities (CA) is needed on your node. The relevant yum repo can be installed issuing:

wget http://repository.egi.eu/sw/production/cas/1/current/repo-files/egi-trustanchors.repo -O /etc/yum.repos.d/egi-trustanchors.repo

Important note on automatic updates

An update of an RPM not followed by configuration can cause problems. Therefore WE STRONGLY RECOMMEND NOT TO USE AUTOMATIC UPDATE PROCEDURE OF ANY KIND.

Running the script available at http://forge.cnaf.infn.it/frs/download.php/101/disable_yum.sh (implemented by Giuseppe Platania (INFN Catania) yum autoupdate will be disabled

Installation of the CA certificates

The CA certificate can be installed issuing:

yum install ca-policy-egi-core 

Installation of the CREAM CE software

To install the middleware software needed for the CREAM CE, install first of all xml-commons-apis: , install first of all xml-commons-apis:

yum install xml-commons-apis 

This is due to a dependency problem within the Tomcat distribution

Then install the CREAM-CE metapackage:

yum install emi-cream-ce

Installation of the batch system specific software

After the installation of the CREAM CE metapackage it is necessary to install the batch system specific metapackage(s).

If you are running LSF, install the emi-lsf-utils metapackage:

yum install emi-lsf-utils

Installation of the cluster metapackage

If the CREAM CE node has to host also the glite-cluster, install also this metapackage:

yum install emi-cluster 


Install host certificate

The CREAM CE node requires the host certificate/key files to be installed. Contact your national Certification Authority (CA) to understand how to obtain a host certificate if you do not have one already.

Once you have obtained a valid certificate:

  • hostcert.pem - containing the machine public key
  • hostkey.pem - containing the machine private key

make sure to place the two files in the target node into the /etc/grid-security directory. Then set the proper mode and ownerships doing:

chown root.root /etc/grid-security/hostcert.pem
chown root.root /etc/grid-security/hostkey.pem
chmod 600 /etc/grid-security/hostcert.pem
chmod 400 /etc/grid-security/hostkey.pem

Using the YAIM configuration tool

For a detailed description on how to configure the middleware with YAIM, please check the YAIM guide.

The necessary YAIM modules needed to configure a certain node type are automatically installed with the middleware.

Configure the siteinfo.def file

Set your siteinfo.def file, which is the input file used by yaim. Documentation about yaim variables relevant for CREAM CE is available at https://twiki.cern.ch/twiki/bin/view/LCG/Site-info_configuration_variables#cream_CE

Run yaim

After having filled the siteinfo.def file, run yaim:

/opt/glite/yaim/bin/yaim -c -s <site-info.def> -n creamCE -n <LRMSnode> [-n glite-CLUSTER]

-n glite-CLUSTER must be specified only if the CREAM CE is in cluster mode AND the glite-CLUSTER is deployed in the same node of the CREAM-CE


  • Configuration of a CREAM CE not in cluster mode using LSF as batch system

     /opt/glite/yaim/bin/yaim -c -s <site-info.def> -n creamCE -n LSF_utils 

  • Configuration of a CREAM CE in cluster mode (with glite-CLUSTER deployed on a different node) using LSF as batch system

     /opt/glite/yaim/bin/yaim -c -s <site-info.def> -n creamCE -n LSF_utils 

  • Configuration of a CREAM CE in cluster mode (with glite-CLUSTER deployed on the same node of the CREAM-CE) using LSF as batch system

     /opt/glite/yaim/bin/yaim -c -s <site-info.def> -n creamCE -n LSF_utils -n glite-CLUSTER

-- MassimoSgaravatto - 2011-04-07

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Topic revision: r3 - 2011-04-07 - MassimoSgaravatto

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