perfSONAR User Q&A and Other Discussion

[Brian Candler <>]

On 17/05/2017 17:47, Mark Feit wrote:
> There is a package in the repository called pscheduler-bundle-full that’s 
> just pScheduler, the standard tests, tools and archivers that we ship and 
> enough for it to do whatever care and feeding it needs.
In the pf3.x model, you could have a "full fat" perfsonar node 
(including scheduler, archiver) which periodically ran tests to a 
stateless remote node (bwctl-server, owamp-server, iperf3).  The remote 
node didn't store anything, and never initiated tests on its own behalf.

If the pf4.x model we have pscheduler, which has a SQL database plus 
pluggable tests and archivers.

Here's what I don't understand. Let's call the node which decides it's 
time to run a test "A", and the one which receives an incoming 
connection and responds "B"

Question 1: when "A" runs a test, are the archivers invoked at both A 
and B ends?  Is there a way to configure B with a null archiver which 
doesn't store the results?

Question 2: assuming "A" uses esmond as archiver, what's the postgres 
database used for?  Is it just storing the configuration of scheduled 
tests?  Or is it storing test history/logs, in addition to the results 
stored in esmond?

Question 3: is it in principle possible to write a databaseless 
pscheduler responder daemon which passively acts on test requests like 
bwctl did?  Or is there something about the new protocol which means a 
persistent database is inherently necessary?

(I did try looking for documentation on the pscheduler protocol, but 
didn't find it)

Question 4: owamp has its own control protocol on well-known port (861). 
Is a perfsonar 4.x node able to run owamp tests to a remote node which 
is running owamp-server but *not* running pscheduler or bwctl?

In the past, I've been able to add bwctl+owamp to an existing server 
with very low overhead. I used it both as an endpoint for interactive 
testing (bwctl at command line) and scheduled testing (from a full 
perfsonar node).  It's a shame if the switch to pscheduler protocol will 
mean this isn't possible any more.

Regards,

Brian.