ATP - VO TOPOLOGY FEEDS

INTRODUCTION

The ATP VO feeds are XML files used by the LHC VOs to define which are the services (among the ones defined by GOCDB and RSV) that they support. At the same time, they can define the name of each existing site as called by the VO.

XML ELEMENTS

The elements of the XML schema are these ones:

  • <root xsi:noNamespaceSchemaLocation="topology_info.xsd">
    - Marks the beginning and end of the XML file and the XSD file to validate the XML
  • <title>CMS Topology Information for ATP</title>
    - Just a title for the VO feed.
  • <description>List of CMS site names for monitoring and mapping to the SAM/WLCG site names</description>
    - A description of the VO feed.
  • <feed_responsible dn="/DC=ch/DC=cern/OU=Org Units/OU=Users/CN=wco/CN=497/CN=Wile E Coyote" name="Wile Coyote"/>
    - Defines who is the person responsible for the content. The DN (certificate Distinguished Name) is an optional attribute.
  • <last_update>2010-03-20T15:25:10Z</last_update>
    - The  complete date plus hours and minutes in W3C format when the information was updated for the last time.
  • <vo>cms</vo>
    - The VO name that defines these groups of services.
  • <group name="services_monitoring" type="CMS">
    - Has two attributes that define a two level hierarchy of information for the VO.
    • The first attribute is the name, used to define a tag for one or more sites and services
    • The second one is the type, understood as the parent of the name, so under one type we can define one or more name. This can be used to query the ATP to retrieve all the groups (services and sites) defined under one single type attribute.
  • <virtual_site name="T0_CH_CERN">
    - Inside a <group/> we define one or more <virtual_site/>s, that are the XML elements whose content are services 
    defined in one or more sites. The 'name' attribute is used to define the name of a site (or group of services) from 
    the VO perspective.
  • Inside each virtual_site XML element, we define:
    • <tier>0</tier>
      - That states which is the Tier level of the virtual_site for the VO.
    • <atp_site name="RAL-LCG2" infrast="EGEE">
         <service hostname="lcgce02.gridpp.rl.ac.uk" flavour="CE"/>
         <service hostname="lcgce03.gridpp.rl.ac.uk" flavour="CE"/>
         <service hostname="lcgce04.gridpp.rl.ac.uk" flavour="CE"/>
      </atp_site>
      <atp_site name="uscms-fnal-wc1-ce4" infrast="OSG"/>
      - and a list of services. This list of services can be defined one by one, or stating the name of a site 
      existing in GOCDB or RSV, in which case all services defined in the authoritative sources are considered.

XML EXAMPLE

To make it more clear, let's consider the following example:

  • <root xsi:noNamespaceSchemaLocation="topology_info.xsd">
      <title>CMS Topology Information for ATP</title>
      <description>
        List of CMS site names for monitoring and mapping to the SAM/WLCG site names
      </description>
      <data_manager href="http://cern.ch" dn="/DC=ch/DC=cern/OU=Org Units/OU=Users/CN=wco/CN=497/CN=Wile E Coyote" name="Wile Coyote"/>
      <vo>cms</vo>
      <group name="services_monitoring" type="CMS">
        <virtual_site name="T0_CH_CERN">
          <tier>0</tier>
          <atp_site name="CERN-PROD" infrast="EGEE"/>
        </virtual_site>
        <virtual_site name="T1_UK_RAL">
          <tier>1</tier>
          <atp_site name="RAL-LCG2" infrast="EGEE">
            <service hostname="lcgce02.gridpp.rl.ac.uk" flavour="CE"/>
            <service hostname="lcgce03.gridpp.rl.ac.uk" flavour="CE"/>
            <service hostname="lcgce04.gridpp.rl.ac.uk" flavour="CE"/>
          </atp_site>
        </virtual_site>
        <virtual_site name="T1_US_FNAL">
          <tier>1</tier>
          <atp_site name="uscms-fnal-wc1-ce4" infrast="OSG"/>
          <atp_site name="uscms-fnal-wc1-ce" infrast="OSG"/>
        </virtual_site>
      </group>
    </root>
    
  • In this example, CMS VO declares that supports all services defined at CERN-PROD site in the EGEE infrastructure, i.e., all services defined in GOCDB under CERN-PROD site. And for CMS, this site is called T0_CH_CERN. Apart from those, under T1_UK_RAL name, CMS supports the three CEs declared in GOCDB RAL-LCG2 site in the lcgce02.gridpp.rl.ac.uk, lcgce03.gridpp.rl.ac.uk and lcgce04.gridpp.rl.ac.uk hosts. Finally, under CMS site name T1_US_FNAL it supports all the services defined by RSV (OSG) in the sites uscms-fnal-wc1-ce4 and uscms-fnal-wc1-ce

SPACE TOKENS

In case you want to specify service meta data information like for instance, space tokens, you can define them inside the declaration of each SRMv2 service, following this as an example:

<service hostname="srm-v2.cr.cnaf.infn.it" flavour="SRMv2" endpoint="srm://srm-v2.cr.cnaf.infn.it:8443/srm/managerv2">
  <spacetoken base_path="SFN=/castor/cnaf.infn.it/grid/lcg/atlas/atlasdatatape/" domain=".*cnaf.infn.it.*/atlasdatatape/.*" name="DATATAPE"/>
  <spacetoken base_path="SFN=/castor/cnaf.infn.it/grid/lcg/atlas/atlasmctape/" domain=".*cnaf.infn.it.*/atlasmctape/.*" name="MCTAPE"/>
</service>

EXAMPLE FILE

You can use this file as a reference to build your VO feed:

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Topic revision: r2 - 2010-03-30 - DavidCollados
 
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