Difference: SystemAdministratorGuideForEMI1 (32 vs. 33)

Revision 332011-10-10 - MassimoSgaravatto

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META TOPICPARENT name="SystemAdministratorDocumentation"

System Administrator Guide for CREAM for EMI-1 release

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  glite-CLUSTER is a node type that can publish information about clusters and subclusters in a site, referenced by any number of compute elements. In particular it allows to deal with sites having multiple CREAM CE nodes and/or multiple subclusters (i.e. disjoint sets of worker nodes, each set having sufficiently homogeneous properties).
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In Glue1, batch system queues are represented through GlueCE objectclasses. Each GlueCE refers to a Cluster, which can be composed by one or more SubClusters. However the gLite WMS requires the publication of exactly one SubCluster per Cluster (and hence per batch queue).
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In Glue1, batch system queues are represented through GlueCE objectclasses. Each GlueCE refers to a Cluster, which can be composed by one or more SubClusters. However the gLite WMS requires the publication of exactly one SubCluster per Cluster (and hence per batch queue).
  Thus sites with heterogeneous hardware have two possible choices:
  • publish a SubCluster with a representative/minimum hardware description (e.g. the minimum memory on any node)
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  • define separate batch queues for each hardware configuration, e.g. low/high memory queues, and attach the corresponding GlueCE objects to separate Cluster/SubCluster pairs. For attributes with discrete values, e.g. SL4 vs SL5, this second option is the only one which makes sense.
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  • define separate batch queues for each hardware configuration, e.g. low/high memory queues, and attach the corresponding GlueCE objects to separate Cluster/SubCluster pairs. For attributes with discrete values, e.g. SL4 vs SL5, this second option is the only one which makes sense.
  However, without the use of the gLite-cluster, YAIM allows configuring a single Cluster per CREAM head node.

A second problem, addressed by gLite-cluster arises for larger sites which install multiple CE headnodes submitting to the same

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batch queues for redundancy or load-balancing. Without the use of gLite-cluster, YAIM generates a separate Cluster/SubCluster pair for each head node even though they all describe the same hardware. This causes no problems for job submission, but by default would overcount the installed capacity at the site by a multiple of the number of SubClusters. The workaround, before introducing the gLite-cluster, was to publish zero values for the installed capacity from all but one of the nodes (but this is clearly far from being an ideal solution).
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batch queues for redundancy or load-balancing. Without the use of gLite-cluster, YAIM generates a separate Cluster/SubCluster pair for each head node even though they all describe the same hardware. This causes no problems for job submission, but by default would overcount the installed capacity at the site by a multiple of the number of SubClusters. The workaround, before introducing the gLite-cluster, was to publish zero values for the installed capacity from all but one of the nodes (but this is clearly far from being an ideal solution).
 
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The glite-CLUSTER node addresses this issue. It contains a subset of the functionality incorporated in the CREAM node types: the publication of the Glue1 GlueCluster and its dependent objects, the publication of the Glue1 GlueService object for the GridFTP endpoint, and the directories which store the RunTimeEnvironment tags, together with the YAIM functions which configure them.
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The glite-CLUSTER node addresses this issue. It contains a subset of the functionality incorporated in the CREAM node types: the publication of the Glue1 GlueCluster and its dependent objects, the publication of the Glue1 GlueService object for the GridFTP endpoint, and the directories which store the RunTimeEnvironment tags, together with the YAIM functions which configure them.
  So, gLite-CLUSTER should be considered:
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  When configuring a gLite-cluster, please consider that there should be:
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  • One cluster for each set of worker nodes having sufficiently homogeneous properties
  • One subcluster for each cluster
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  • There should be one cluster for each set of worker nodes having sufficiently homogeneous properties
  • There should be one subcluster for each cluster
  • Each batch system queue should refer to the WNs of a single subcluster
 

glite-CLUSTER can be deployed in the same host of a CREAM-CE or in a different one.

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The following deployment models are therefore possible for a CREAM-CE:
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The following deployment models are possible for a CREAM-CE:

 
  • CREAM-CE can be configured without worrying about the glite-CLUSTER node. This can be useful for small sites who don't want to worry about cluster/subcluster configurations because they have a very simple setup. In this case CREAM-CE will publish a single cluster/subcluster. This is called no cluster mode. This is done as described below by defining the yaim setting CREAMCE_CLUSTER_MODE=no (or by no defining at all that variable).
  • CREAM-CE can work on cluster mode using the glite-CLUSTER node type. This is done as described below by defining the yaim setting CREAMCE_CLUSTER_MODE=yes. The CREAM-CE can be in the same host or in a different host wrt the glite-CLUSTER node.
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0.0.1 Installation of the CREAM CLI

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The CREAM CLI is part of the EMI-UI. To install it please refer to xxx.
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The CREAM CLI is part of the EMI-UI. To install it please refer to https://twiki.cern.ch/twiki/bin/view/EMI/EMIui#Client_Installation_Configuratio .
 

0.1 Configuration

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  Set your siteinfo.def file, which is the input file used by yaim. Documentation about yaim variables relevant for glite-CLUSTER is available at https://twiki.cern.ch/twiki/bin/view/LCG/Site-info_configuration_variables#CLUSTER
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You should have:

  • One cluster for each set of worker nodes having sufficiently homogeneous properties
  • One subcluster for each cluster

xxx tanti cluster quanti sono questi set disgiunti 1 subcluster per cluster 1 coda deve essere configurata per usare solo i WNs di un subcluster

 

0.0.0.1 Run yaim

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0.0.1 Configuration of the CREAM CLI

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The CREAM CLI is part of the EMI-UI. To configure it please refer to xxx.
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The CREAM CLI is part of the EMI-UI. To configure it please refer to https://twiki.cern.ch/twiki/bin/view/EMI/EMIui#Client_Installation_Configuratio.
 

0.0.1 Manual configuration

 
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