[glue-wg] Entity descriptions

[Maarten.Litmaath at cern.ch]

Hi Stephen,

> I have an action to provide general descriptions for half of the
> computing entities, and this is my attempt. I think we also need better

Looks good.  Some minor corrections inline.

> descriptions for many of the attributes, but I'd rather do that by
> editing the file. I'm not sure if we should say anything about how GLUE
> 1 concepts map to GLUE 2, but it may be helpful.
> 
> ExecutionEnvironment
> 
> The ExecutionEnvironment class describes the hardware and operating
> system environment in which a job will run. It represents a set of
> homogeneous Worker Nodes, so if a computing system contains nodes with
> significantly different properties there may be several
> ExecutionEnvironment instances. (This is similar to the GlueSubCluster
> object in GLUE 1.) This implies that it should be possible to request a
> specific environment when a job is submitted. The ExecutionEnvironment
> may refer to virtual rather than physical machines.
> 
>   As well as attributes describing a typical node, the class gives
> summary information about the size and usage of the set of nodes which
> posess those properties. However, there is no way to relate these to the
| ^^^^^^
| possess those properties. However, there is no way to relate these to the

> information in other entities, e.g. it is not possible to know which
> jobs in a given ComputingShare are running on which
> ExecutionEnvironment.
> 
> ApplicationEnvironment
> 
> The ApplicationEnvironment class describes the software environment in
> which a job will run, i.e. what pre-installed software will be available
> to it. Each Application is identified by a name (the AppName attribute);
> these names are not defined within the schema, but SHOULD be assigned in
> a way which allows applications to be uniquely identifed. The properties
|                                                ^^^^^^^^^
| a way which allows applications to be uniquely identified. The properties

> of installed software may vary substantially, but the attributes of the
> class cover the most common cases, in particular for licensed software.
> If necessary, additional information can be added using the OtherInfo
> attribute and the Extension class.
> 
> ApplicationHandle
> 
> The ApplicationHandle class is an extension to ApplicationEnvironment
> for applications which need to be set up in some way before they can be
> used. For each supported setup method a string can be specified, the
> interpretation of which is specific to the method - in the simplest case
> this could just be a setup script to execute.
> 
> ComputingActivity
> 
> The ComputingActivity class represents a single (but possibly
> multi-processor) job. The attributes give the job properties and state
> as seen by the local batch system, together with some Grid-level
> information.
> 
> ToStorageService
> 
> The ToStorageService class represents the case where a filesystem from a
> Storage Service is available to jobs running on a Computing Service via
> posix access, e.g. as an NFS mount. Each ToTorageService instance
| ^^^^^                                    ^^^^^^^^^^^^^^^
| POSIX access, e.g. as an NFS mount. Each ToStorageService instance

> represents a single mount point. It is assumed that such mounts are
> available on all nodes (i.e. all Execution Environments) in the
> Computing Service.