Info Providers on Phoenix

These pages are a collection of information on the information providers used by the LCG / EGEE middleware and how they are configured on the Phoenix cluster.

Basics

The EGEE/LCG info providers are based on LDAP and is called BDII for 'Berkeley Database Info Index' because the LDAP info is cached in a local BDB. The layout is hierarchical, i.e. each service / resource publishes its own resource information in its local BDII. As of glite 3.1, the BDII always runs on port 2170 (no more Globus MDS on port 2135). To query a certain resource, issue the command

ldapsearch -x -h [hostname] -p 2170 -b "mds-vo-name=resource,o=grid"

The configuration of the service BDII lives in /opt/glite/etc/gip.

The individual resource (service) informations are then collected at the site BDII which at CSCS is configured to be on the ce01.lcg.cscs.ch. In order to query the information of the whole site, issue

ldapsearch -x -h ce01.lcg.cscs.ch -p 2170 -b "mds-vo-name=CSCS-LCG2,o=grid"

If you would just query for resource instead of CSCS-LCG2, only the information about the CE would be returned. The information of the site BDII is then queried and concatenated at the central top-level BDII at CERN. It can be queried as

ldapsearch -x -h lcg-bdii.cern.ch -p 2170 -b "Mds-Vo-name=CSCS-LCG2,mds-vo-name=local,o=grid"

Information of any other site can be queried by replacing CSCS-LCG2 with the corresponding site name.

See also

• The Generic Information Provider documentation in the CERN wiki
  • Generic Information Provider short description
  • Infosystem Troubleshooting a useful page explaining what to do to debug the system
  • Glue configuration proposal for SRM 2.2 by the GSSD team (also a good link!)
  • Stephen Burke's ldapsearch tutorial

The problem with the GIP and consorts is that the locations of files, content of configurations is different in our setup than in most of the documentation.

CE Information Provider

First of all, to see if the dynamic information provided is correct, look at this page: Testing Dynamic Information

The CE information provider is running on ce01.lcg.cscs.ch. To run it by hand, which will produce an ldap-like output, issue

      /opt/glite/libexec/glite-info-generic /opt/glite/etc/gip/glite-info-generic.conf

This will give you the same information as should be returned by querying the CE resource as explained above:

     ldapsearch -x -h ce01.lcg.cscs.ch -p 2170 -b mds-vo-name=resource,o=grid

The inner workings of this are as described on the GIP page. The dynamic plugin which provides information about each VO's usage of the queue is in the plugin directory at

     /opt/glite/etc/gip/plugin/glite-info-dynamic-scheduler-wrapper

This is executed to produce an ldif file with dynamic information on the scheduler's properties. In order to make this work, there is a configuration file at

     /opt/glite/etc/lcg-info-dynamic-scheduler.conf

VOView Check

Compare the output of

ldapsearch -x -h ce01.lcg.cscs.ch -p 2170 -b "mds-vo-name=resource,o=grid" \
"(objectClass=GlueVOView)"

with the regular qstat -q command, you will see that the numbers match.

SRM Check

To print the SRM endpoint information, issue

ldapsearch -x -h ce01.lcg.cscs.ch -p 2170 -b "mds-vo-name=CSCS-LCG2,o=grid" \ 
"(&(GlueServiceUniqueID=*)(objectClass=GlueService)(GlueServiceType=SRM)(objectClass=glueService))"

To see the path by which the lcg-utils assemble the pathname, issue

ldapsearch -x -h ce01.lcg.cscs.ch -p 2170 -b "mds-vo-name=CSCS-LCG2,o=grid" \ 
| grep GlueSAPath

SE Info Provider

The info provider on storage01.lcg.cscs.ch publishes information about the SE, the StorageAreas and the tokens. It lives at /opt/glite/etc/gip on that machine, and most of the information it provides is static:

• ldif/static-file-SE.ldif - this provides the information skeleton for all VO spaces.
• ldif/static-file-dSE.ldif - this provides information on the SRM v1 and v2 endpoints, should become eventually part of the dynamic providers

However, there are also dynamic providers. It is done by implementing a dCache cell, the infoProvider cell, which simply gathers some statistics on free and used space and replaces the zero values from the static-file-SE.ldif with real values and also actually provides information about the various SEAccessProtocols. The script that is provided by dcache is linked at

• provider/infoDynamicSE-provider-dcache - this provides the GlueSEAccessProtocol values
• plugin/infoDynamicSE-plugin-dcache - this fills in the values for GlueSATotalOnlineSize, GlueSAUsedOnlineSize, etc.

-- PeterKunszt - 02 Oct 2007