Querying the Information System

About the information system

Information about resources is documented according to the GLUE Schema.

Information in the Top BDII is provided for two GLUE schema versions:

GLUE 1.3: the legacy version of the specification, under the LDAP base Mds-Vo-Name=local,o=grid.
GLUE 2.0: the most recent version of the specification, under the LDAP base GLUE2GroupID=grid,o=glue.

Some resources may not yet be exposed via GLUE 2.0, and it may be required to use GLUE 1.3 for those ones.

Tip

You can use -o ldif-wrap=no to disable wrapping the results.

Those examples are relying on the Top BDII service maintained by EGI Foundation: ldap://lcg-bdii.egi.eu:2170.

# Dumping all the information from GLUE 2.0
$ ldapsearch -x -H ldap://lcg-bdii.egi.eu:2170 -b "GLUE2GroupID=grid,o=glue"

In order to retrieve information required to contact a given CE, you can look for GLUE2EndpointURL objects.
In order to retrieve information about the batch systems, you can look for GLUE2Manager objects.
In order to look for information about a specific CE, you can look into GLUE2Service.
In order to look for information about the resources available to VOs, you can look into GLUE2Share and GLUE2Policy.

The following queries can be used to retrieve information about all the Computing Elements of a given type. You will likely be able to use only a subset of them, only the ones supporting the Virtual Organisation you are a member of, and for which you have a valid VOMS proxy.

Computing Elements

Nowadays mainly two Computing Element (CE) “flavours” are used in production:

HTCondorCE, a Compute Entrypoint (CE) based on HTCondor.
ARC-CE, the ARC Compute Element (CE).

The CREAM CE is a legacy and no more supported middleware.

Querying for HTCondorCE compute resources

Most, if not all the HTCondorCE Computing Elements should be discoverable via GLUE 2.0.

# Querying GLUE2EndpointURL for all HTCondorCE compute endpoints
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Endpoint)(GLUE2EndpointImplementationName=HTCondor))' \
    GLUE2EndpointInterfaceName \
    GLUE2EndpointImplementationVersion \
    GLUE2EndpointURL

# Querying GLUE2Manager for the batch systems' versions and number of CPUs
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
   '(&(objectClass=GLUE2Manager)(GLUE2ManagerProductName=HTCondor))' \
   GLUE2ManagerProductName \
   GLUE2ManagerProductVersion \
   GLUE2ComputingManagerTotalLogicalCPUs \
   GLUE2ComputingManagerComputingServiceForeignKey

Once you have selected a given CE, you can look into getting more information about this one.

# Querying GLUE2Service for information about a specific CE
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Service)(GLUE2ServiceID=*condorce1.ciemat.es*))'

# Querying GLUE2Share for a specific CE, filtering for details on the queues
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Share)(GLUE2ShareID=*condorce1.ciemat.es*))' \
    GLUE2ComputingShareMappingQueue \
    GLUE2ShareIDGLUE2ComputingShareMaxWallTime \
    GLUE2ComputingShareMaxVirtualMemory \
    GLUE2ComputingShareMaxUserRunningJobs \
    GLUE2ComputingShareMaxRunningJobs \
    GLUE2ComputingShareMaxCPUTime \
    GLUE2ComputingShareWaitingJobs \
    GLUE2ComputingShareUsedSlots \
    GLUE2ComputingShareTotalJobsGLUE2ComputingShareRunningJobs

# Querying GLUE2Policy for a specific CE, filtering for supported VOs
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Policy)(GLUE2PolicyID=*condorce1.ciemat.es*))' \
    GLUE2PolicyRule \
    GLUE2PolicyID \
    GLUE2MappingPolicyShareForeignKey

It’s also possible to look into GLUE 1.3.

Querying for ARC-CE compute resources

Most, if not all the ARC-CE should be discoverable via GLUE 2.0.

# Querying for all ARC-CE compute resources
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Endpoint)(GLUE2EndpointImplementationName=nordugrid-arc))' \
    GLUE2EndpointInterfaceName \
    GLUE2EndpointImplementationVersion \
    GLUE2EndpointURL

# Querying GLUE2Manager for the batch systems' versions and number of CPUs
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
   '(&(objectClass=GLUE2Manager)(GLUE2ComputingManagerComputingServiceForeignKey=*urn:ogf:ComputingService*))' \
   GLUE2ManagerProductName \
   GLUE2ManagerProductVersion \
   GLUE2ComputingManagerTotalLogicalCPUs \
   GLUE2ComputingManagerComputingServiceForeignKey

Once you have selected a given CE, you can look into getting more information about this one.

# Querying GLUE2Service for information about a specific CE
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Service)(GLUE2ServiceID=*alex4.nipne.ro*))'

# Querying GLUE2Share for a specific CE, filtering for details on the queues
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Share)(GLUE2ShareID=*alex4.nipne.ro*))' \
    GLUE2ComputingShareMappingQueue \
    GLUE2ShareIDGLUE2ComputingShareMaxWallTime \
    GLUE2ComputingShareMaxVirtualMemory \
    GLUE2ComputingShareMaxUserRunningJobs \
    GLUE2ComputingShareMaxRunningJobs \
    GLUE2ComputingShareMaxCPUTime \
    GLUE2ComputingShareWaitingJobs \
    GLUE2ComputingShareUsedSlots \
    GLUE2ComputingShareTotalJobsGLUE2ComputingShareRunningJobs

# Querying GLUE2Policy for a specific CE, filtering for supported VOs
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Policy)(GLUE2PolicyID=*alex4.nipne.ro*))' \
    GLUE2PolicyRule \
    GLUE2PolicyID \
    GLUE2MappingPolicyShareForeignKey

It’s also possible to look into GLUE 1.3.

Using GLUE 1.3

GLUE 1.3 is legacy.

Querying for information about HTCondor CE using GLUE 1.3.

# Querying for all HTCondorCE compute resources, using GLUE 1.3
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "Mds-Vo-Name=local,o=grid" \
    '(&(objectClass=GlueCE)(GlueCEInfoJobManager=HTCondorCE))' \
    GlueCEImplementationVersion GlueCEImplementationName \
    GlueCEStateStatus GlueCEUniqueID GlueServiceEndpoint GlueServiceType

# Querying information about the HTCondor CE via GLUE 1.3
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "Mds-Vo-Name=local,o=grid" \
    '(&(objectClass=GlueCE)(GlueCEUniqueID=condorce1.ciemat.es:9619/condorce1.ciemat.es-condor))'

# Limiting output for the Condor CE via GLUE 1.3
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "Mds-Vo-Name=local,o=grid" \
    '(&(objectClass=GlueCE)(GlueCEUniqueID=condorce1.ciemat.es:9619/condorce1.ciemat.es-condor))' \
    GlueCEInfoHostName GlueCEUniqueID \
    GlueCEInfoJobManager GlueCEImplementationName GlueCEImplementationVersion \
    GlueCEInfoLRMSType GlueCEInfoLRMSVersion \
    GlueCEAccessControlBaseRule \
    GlueCEInfoTotalCPUs \
    GlueCEStateStatus

Querying for information about ARC-CE using GLUE 1.3.

# Querying for all ARC CE compute resources, using GLUE 1.3
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "Mds-Vo-Name=local,o=grid" \
    '(&(objectClass=GlueCE)(GlueCEInfoJobManager=arc))' \
    GlueCEImplementationVersion GlueCEImplementationName \
    GlueCEStateStatus GlueCEUniqueID GlueServiceEndpoint GlueServiceType

# Querying information about the ARC CE via GLUE 1.3
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "Mds-Vo-Name=local,o=grid" \
    '(&(objectClass=GlueCE)(GlueCEUniqueID=alex4.nipne.ro:2811/nordugrid-SLURM-dteam))'

# Limiting output for the ARC CE via GLUE 1.3
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "Mds-Vo-Name=local,o=grid" \
    '(&(objectClass=GlueCE)(GlueCEUniqueID=alex4.nipne.ro:2811/nordugrid-SLURM-dteam))' \
    GlueCEInfoHostName GlueCEUniqueID \
    GlueCEInfoJobManager GlueCEImplementationName GlueCEImplementationVersion \
    GlueCEInfoLRMSType GlueCEInfoLRMSVersion \
    GlueCEAccessControlBaseRule \
    GlueCEInfoTotalCPUs \
    GlueCEStateStatus

Using legacy tools for GLUE 1.3

Using lcg-info it’s possible to easily do more targeted queries, like focusing on a specific VO.

lcg-info and lcg-infosites are only taking into account the GLUE 1.3 schema, and will lack information that is only published according to the GLUE 2 schema, like for most HTCondorCE Computing Elements.

# Identify compute resources available for dteam VO
$ lcg-info --list-ce --vo dteam --bdii ldap://lcg-bdii.egi.eu:2170
# Identify storage resources available for dteam VO
$ lcg-info --list-se --vo dteam --bdii ldap://lcg-bdii.egi.eu:2170

$ lcg-info --list-ce --vo dteam --bdii ldap://lcg-bdii.egi.eu:2170 \
    --attrs CEImpl --query 'CEImpl=*HTCondorCE'
(...)
- CE: ce01.knu.ac.kr:9619/ce01.knu.ac.kr-condor
  - CEImpl              HTCondorCE

- CE: ce13.pic.es:9619/ce13.pic.es-condor
  - CEImpl              HTCondorCE
(...)
- CE: condorce1.ciemat.es:9619/condorce1.ciemat.es-condor
  - CEImpl              HTCondorCE

- CE: condorce2.ciemat.es:9619/condorce2.ciemat.es-condor
  - CEImpl              HTCondorCE
(...)

We can see that the dteam VO should be able to access Computing Elements from the various types:

$ lcg-info --list-ce --vo dteam --bdii ldap://lcg-bdii.egi.eu:2170 \
    --attrs CEImpl --query 'CEImpl=*' | grep CEImpl | sort | uniq -c
    123   - CEImpl              ARC-CE
     22   - CEImpl              CREAM
      7   - CEImpl              HTCondorCE

Identifying all the resources accessible by a given VO

In GLUE 2.0, the access granted to a given VO to a compute or storage resource, is published using the GLUE2Share and GLUE2Policy objects. There are also GLUE2ComputingShare and GLUE2StorageShare to specifically document sharing of compute or storage resources.

# Querying GLUE2Share for all the resources available to dteam VO
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2Share)(GLUE2ShareID=*dteam*))'

# Querying GLUE2ComputingShare for all the computing resources available to dteam VO
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2ComputingShare)(GLUE2ShareID=*dteam*))'

# Querying GLUE2StorageShare for all the storage resources available to dteam VO
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2StorageShare)(GLUE2ShareID=*dteam*))'

It is possible to filter for the different types of Computing Element, and select only specific attributes.

Looking for a HTCondorCE for dteam

# Information about the HTCondorCE supporting dteam VO
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2ComputingShare)(GLUE2ShareID=*dteam*)(GLUE2ComputingShareComputingEndpointForeignKey=*HTCondorCE*))' \
    GLUE2ShareEndpointForeignKey \
    GLUE2ShareID \
    GLUE2ComputingShareTotalJobs \
    GLUE2ComputingShareRunningJobs \
    GLUE2ComputingShareWaitingJobs

Assuming it was decided, based on the site location, available resources, prior experience, or any other reason, to go for condorce1.ciemat.es, the information about the CE can be requested using the following request, filtering on the GLUE2ShareID from the previous query: grid_dteam_condorce1.ciemat.es_ComputingElement.

# condor_submit needs CE (condorce1.ciemat.es) and pool (condorce1.ciemat.es:9619)
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2ComputingShare)(GLUE2ShareID=*grid_dteam_condorce1.ciemat.es_ComputingElement*))' \
    GLUE2ShareID \
    GLUE2ShareDescription \
    GLUE2ComputingShareExecutionEnvironmentForeignKey \
    GLUE2EntityOtherInfo

Looking for an ARC-CE for dteam

# Information about the ARC-CE supporting dteam VO
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2ComputingShare)(GLUE2ShareID=*dteam*)(GLUE2ComputingShareComputingEndpointForeignKey=*urn:ogf*))' \
    GLUE2ComputingShareComputingEndpointForeignKey \
    GLUE2ShareEndpointForeignKey \
    GLUE2ComputingShareTotalJobs \
    GLUE2ComputingShareRunningJobs \
    GLUE2ComputingShareWaitingJobs

# arcsub needs CE name (alex4.nipne.ro)
$ ldapsearch -x -LLL -H ldap://lcg-bdii.egi.eu:2170 \
    -b "GLUE2GroupID=grid,o=glue" \
    '(&(objectClass=GLUE2ComputingShare)(GLUE2ShareID=*urn:ogf:ComputingShare:alex4.nipne.ro:dteam_dteam*))' \
    GLUE2ShareID \
    GLUE2ShareDescription \
    GLUE2ComputingShareComputingServiceForeignKey \
    GLUE2ComputingShareExecutionEnvironmentForeignKey

Last modified March 10, 2023 by Gianni Dalla Torre : General guidelines, SSH setup options, tips, and examples for setting up the OpenStack environment. (#544)