[Go-essp-tech] Selecting GridFTP Server Types in the Replication Client

[Gavin M. Bell]

Hi Craig,

Perhaps I can help elucidate some things.  This is at least how I see
things moving forward.
The key thing is that you need information about nodes and what they
have running on them, specifically GridFTP and what configuration is
supported.

In the current ESGF P2P Node there is a registry service that comes with
every node and is present in all configurations.  The registry's
external view is an XML file that adheres to an xsd that Rachana, Neill,
Philip, Eric and myself put together.  This xml file will contain
essentially a manifest of all nodes participating in the P2P federation
including what services are running on them.  For services like the
gateway, that currently doesn't run directly in the P2P architecture,
any peer can be contacted for this information.  For example PCMDI3 will
be a peer that can be contacted for inspection of the registry, but
PCMDI3 is no more special that any other node that is present in the P2P
federation - so by convention instead of by construction PCMDI3 is a
name we all know and love and will be albe to go to.  So, you may
inspect the registration information on the node you are running the
replication client on for the information you need i.e. gridftp nodes,
their configuration and ports and such.

I have attached a quick registration.xml document from a test node, it
only contains two node entries at the moment, but that should be enough
to illustrate that there may be many more nodes represented in the same
fashion.  Note the context that you should read this in is that each
node is advertising the services it has running.  It is up the the
"reader" to glean from this collection other derivative information,
like, 'which nodes are running gridftp services in a particular
configuration', 'which what nodes are pointing to a particular IDP', etc.

I think this solves your questions, essentially get the info straight
from the horses mouth (aka the registry running on the nodes where the
data lives).  Does this help?  Let me know if there are bits of
information that you don't find accommodated so we can have them present
if needed. :-)  Between the registry and the search api you should be
golden. I know you have recently installed the P2P Node, so you may
already have the manager in place.  The version is v0.5.0 (check
/etc/esg.install_log and look for the esgf-node-manager entry).

P.S.
I would suggest that folks start upgrading their node installations.  We
are doing a bit of cleanup and spit and polish on our respective ESGF
P2P Node components, but what is posted right now, is ready - modulo
spit and/or polish. :-).  I am the last man standing with some
installation cleanup, however, by end of next week we will "release the
hounds"! The intrepid may go at it now. ...(Hmmm.. that reminds me... we
have a lot of documentation to post as well.)

On 5/17/11 3:23 PM, Craig E. Ward wrote:
> On the GO-ESSP call today, we bounced around some ideas about how replication 
> could distinguish between the different types of GridFTP servers that the ESG 
> Federation will have. This is what I heard. I'd like to make sure we're all on 
> the same page.
>
> A naming convention will be applied to the a relevant property (Which 
> property?) that will mark a particular service as either "normal" GridFTP or 
> the ESG-security-specific (i.e. BDM) GridFTP. The replication client will use 
> an appropriate name when selecting services for the user's preferred data 
> movement agent.
>
> This also requires a new configuration option for the replication client that 
> allows the user to control what the which service to use in the transfer 
> control file.
>
> In the meta data XML, the replication client is looking at the name stored for 
> "data_access_capability." The default value to match is "GridFTP." It isn't 
> clear to me where this value is coming from, but the "serviceType" attribute of 
> the "service" element in the TDS catalog is set to "GridFTP" for that type of 
> protocol. Is the gateway placing the "serviceType" value into the 
> "data_access_capability" attribute?
>
> In another thread, Bob wrote about restrictions on what names were allowed at 
> certain points. If so, this could complicate the issue, but not prevent this 
> solution from working.
>
> Who remembers things differently?
>
> Thanks,
>
> Craig
>

-- 
Gavin M. Bell
--

 "Never mistake a clear view for a short distance."
       	       -Paul Saffo


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