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manual:glitemce

gLite mCE

About

The taks of the gLite mCE component is to forward gLite jobs to 3G Bridge services. That is, it operates as a bridge between gLite and grids supported by the 3G Bridge. The typical usage scenario for the gLite mCE component is to forward gLite jobs to desktop grids.

Prerequisites

The gLite mCE component can be installed over a properly configured EMI-2 gLite CE node. Please consult the current EMI documentation on how to perform this deployment.

Installation

Installation consists of the following steps:

  1. add the EDGI repo to the repository list,
  2. install the necessary mCE packages (gLite component and Yaim configuration package).

Add the EDGI repo

Add the following content to file /etc/yum.repos.d/edgi.repo:

[edgi]
name=EDGI Grid Deployment
baseurl=http://www.edgi-grid.eu/downloads/repo/sl6
enabled=1
protect=1

Once done, run yum update.

Install the mCE packages

Run the following command to run the necessary mCE packages:

$ yum install edgiexecutor

This will install the necessary Yaim configuration package (glite-yaim-edgi-bridge) as well.

Configuration

In the gLite mCE, each CE queue forwards jobs to a specific 3G Bridge service. The configuration of this association is described here. If you're interested in how to configure queues, VOs and VO-queue associations, please consult the EMI documentation.

Copy the file /opt/glite/yaim/examples/siteinfo/services/glite-edgi_bridge to a file called services/glite-edgi_bridge in your CE's Yaim configuration directory (where your site-info.def file resides). The source files provides an example configuration for the gLite mCE with multiple queues enabled. An example on how to prepare the file is as follows:

$ cd ~/glite
$ mkdir -p services
$ cp /opt/glite/yaim/examples/siteinfo/services/glite-edgi_bridge services/glite-edgi_bridge
$ vim services/glite-edgi_bridge

Modify the following configuration variables according to your setup in the glite-edgi_bridge file:

  • EDGI_AR_URL: specifies the URL of the EDGI Application Repository. Leave this field empty with configurations without an EDGI AR
  • EDGI_AR_FILEPREFIX: specifies prefix of file URLs stored within the EDGI AR. Once logged in to the EDGI AR, you can get this prefix by querying files of some of the applications, and removing the application-specific part. Leave this field empty with configurations without an EDGI AR
  • EDGI_STORAGE_PREFIX: specifies the filesystem path where the mCE should put inputs of jobs. These files will be downloaded by the 3G Bridge services. Please see additionally the EDGI_HTTP_URL variable as well
  • EDGI_HTTP_URL: specifies the URL through which files stored under EDGI_STORAGE_PREFIX are available for download. For example, if EDGI_STORAGE_PREFIX is specified as /var/edgi/www/edgice, and EDGI_HTTP_URL is set as http://foo.bar/edgice, then the URL http://foo.bar/edgice/15/15569b3d12335143dc74b934a507003f should download file /var/edgi/www/edgice/15/15569b3d12335143dc74b934a507003f. One can use lighttpd or Apache to provide the web service
  • <QUEUENAME>_3G_SERVER: for each queue, this variable specifies information on how to connect to the 3G Bridge service. The format of the variable is as follows: <DG_URL>,<WSSUBMITTER_HOST>:<WSSUBMITTER_PORT>,<3G_BRIDGE_GRID_ID>[,<GBAC_APPLICATION_NAME>] where <DG_URL> is the URL of the public interface of the desktop grid (e.g. http://szdg.lpds.sztaki.hu/szdg for the SZTAKI Desktop Grid), <WSSUBMITTER_HOST> and <WSSUBMITTER_PORT> are the hostname (e.g. http://foo.bar) and port (e.g. 8091) where the WSSubmitter service providing the target 3G Bridge's web service interface is running, <3G_BRIDGE_GRID_ID> is the grid name as configured in 3G Bridge, and the optional <GBAC_APPLICATION_NAME> contains the name of the GBAC application as registered in the target 3G Bridge service.

Once all the configuration files have been set, one may perform the configuration using a command similar to the following:

$ /opt/glite/yaim/bin/yaim -c -s site-info.def -n creamCE -n EDGI_bridge

Troubleshooting

In case of any error encountered, one should examine the following log files:

  1. /var/log/cream/glite-ce-cream.log: CREAM CE and mCE logs go here,
  2. /var/log/tomcat5/catalina.out: higher-level logs/exceptions go here.
manual/glitemce.txt · Last modified: 2013/01/18 09:49 by smith