Site to Resource Mapping rfc

RFC #9

Author: A.Tsaregorodtsev

Last Modified: 8.03.2013

In various production activities it is necessary to associate a given set of resources to sites and vice versa. For example, Storage Elements that are allowed for access from a given Site within a given activity. Obviously activities can depend on a VO and Setup. Therefore, it is suitable to describe those associations ( mappings ) in the /Operations section of the Configuration Service.

Mappings in the /Operations section

The proposed CS structure for describing mappings is illustrated by the following example:

<Operations> {
  SiteToStorageMapping {
    Close {
       CERN.ch = CERN-disk, CERN-DST
       UseLocalResources = True
    }
    MCDataUpload
    {
       Manchester.uk = RAL-DST
       Imperial.uk = RAL-DST
       PIC.es = IN2P3-DST
    }
    NeverUse
    {
       IHEP.cn = CERN-tape
    }
  }
  SiteToDBServerMapping
  {
    ProductionConditions
    {
      Manchester.uk = RAL-Oracle
      LAL.fr = IN2P3-MySQL
    }
  }
}

As it is seen in the example, the mappings have the following properties:

• there can be different mappings defined with arbitrary names used in different VO's production systems
• mapping can be defined for any "Resource Type"
• mappings can be defined independently for different Setups, e.g. Production and Certification
• UseLocalResources flag suggests that eligible resources belonging to the site must be added to the resulting set of mapped resources

In the code the mappings are accessed with a Operations helper:

from DIRAC.ConfigurationSystem.Client.Helpers.Operations import Operations
...
operationsHelper = Operations( vo = vo )
result = operationsHelper.getSiteMapping( 'Storage', 'Close' )
if result['OK']:
  storageElementsForCERN = result['Value'].get('CERN.ch',[])

result = operationsHelper.getResourceMapping( 'Storage', 'Close' )
if result['OK']:
  sitesUsingRDSTatCERN = result['Value'].get('CERN-RDST',[])

The helper will take into account the mappings defined in the <Operations> sections but will also return only the resources eligible for usage by the given VO. To do that the Operations helper will use internally the Resources helper.