[jsdl-wg] Questions about JSDL schema

[Andreas Savva]

Hi

I got an action at the last teleconf to followup on the 
filesystem/mountpoint/diskspace issues Ariel raised. Sorry for being 
late with this.

 (I've edited/re-arranged the two emails to gather the relevant parts 
together)

Donal K. Fellows wrote:

> Ariel Oleksiak wrote:

    :

>> 11. Within the FileSystem element there is a sub-element MountPoint. Who
>> should specify this? A user? I think a more common use case is that 
>> users
>> use predefined variables (e.g. home, tmp) to specify paths that are 
>> relative
>> to these variables (but mount points depend on a local system).
>
>
> IIRC, the user can specify it and the system can either ensure that the
> FS is mounted, or it can just check to see if it is mounted and throw
> the job out if it isn't. 

    :

>
>> But MountPoint is a mandatory element. How to specify required disc 
>> space without knowledge about mount points on local systems?
>
> IIRC, the mount point does not need to be associated with an explicit
> location. (I hope someone else will try to answer this question!)
>

There are 3 scenarios here:
  1. User specifies that certain filesystems must be available at a 
certain locations
  2. User specifies certain filesystems must be available but doesn't 
care where, as long as the information is passed  back somehow, e.g., 
environment variables.
  3. User only cares that sufficient DiskSpace is available because 
there is access to some other mechanism that will deploy/configure the 
resource before the job is executed.

At the moment we clearly support (1) and somewhat obsurely (2), and 
perhaps even (3) as Donal mentions. If we agree that these 3 scenarios 
are equally valid I wonder if we shouldn't make the rules clearer. For 
example:
 - make the MountPoint optional
 - if the MountPoint is specified then the filesystem MUST be available 
at that location
 - if the MountPoint is not specified then the filesystem MUST be 
available at some location and there MUST be an environment variable 
(subject to the rules of ApplicationType) defined by the execution 
system with the same name as the "FileSystem id". The value of this 
environment variable MUST be the location of the filesystem.

And for case (3) we could allow the DiskSpace element to appear directly 
under Resource.

Andreas