[Ops] Note draft: "Operational Identification"

[Mark Taylor]

Markus, Pierre, all,

a few comments on comments.

On Fri, 5 Mar 2021, Markus Demleitner wrote:

> I inadvertently replied to Pierre directly (rather than the list)
> when I commented on his post.  Ahem.  Let me take this opportunity to
> make some of my points in public:
> 
> On Thu, Mar 04, 2021 at 05:08:39PM +0000, Mark Taylor wrote:
> > On Mon, 1 Mar 2021, Pierre Fernique wrote:
> > > types of op-purpose: validate, monitor, harvest.I think the first two 
> > > will be not so easy to differentiate. In practice, they are usually the 
> > > same tools that perform both functions, and it is unlikely that 
> > > developers will modify the User-agent to suit the use that the user will 
> > > be made of it. Maybe keep only one term: "check" ? Also, the notion of 
> > 
> > I agree that there will be grey areas between validation and monitoring,
> > though e.g. most of the activities that I can recall being presented 
> > in recent Ops IG sessions fall fairly clearly into one or the other
> > category (e.g. the weather reports carried out by VO-Paris and ESAC,
> > and taplint are validation activities, while the servicemon tool
> > presented by Tom Donaldson at the last interop was monitoring).
> > But it's true that the distinction is not that important for the
> > purposes that I'd envisage - identifying which queries are
> > non-science ones.  I'd be inclined to keep the terms "validate"
> > and "monitor", but I don't have very strong feelings about it,
> > so if others think "check" would be better, we can change it.
> 
> I'd have said "monitoring" is a repetitive, timed activity (which
> would include the weather report checks for me), whereas validation
> is something more or less initiated by a user (such as the RofR
> validator).

... which isn't the distinction I'd make.  I'd have said that
validation is testing correctness, while monitoring is testing
liveness or performance; either could be automated/repetitive
or human-initiated.

Given that the distinction is evidently a matter of debate,
maybe Pierre is right, we should collapse these to a single term -
"check" or "test".

> The reason I believe it makes sense to tell these two apart is that
> if I have a load spike due to validation I can relax because it'll be
> rare.  Load spikes due to monitoring would be concern.

I'd say that the important thing is just to distinguish 'operational'
from 'science' queries.  In practice if I was looking at these things
I can imagine just grepping for "(IVOA-" and use the statistics and
the rest of the User-Agent content to work out what's really going on -
I don't think we should attempt anything too fine-grained with these
headers.  However, since I don't run a service that's not something
I'm actually likely to have to do, so input from those that have
attempted this or expect to do so would be useful.

> > > "harvest" may be too "VO registry" oriented and very limited in 
> > > practice. I'm afraid it won't be used for other inter-center data 
> > > synchronization operations. It would probably be interesting to enlarge 
> > > its usage by giving some other examples for the use of this 
> > > "op-purpose": Synchronizing data from one server to another server => 
> > > notably Hipsgen MIRROR could use this term, or Simbad's recurring global 
> > > queries for populating partner DBs. I was also wondering about the 
> > 
> > That sounds reasonable, maybe a more neutral term like "mirror" would
> > be better?  Markus as more of a registry expert than me might want to
> > comment.
> 
> In my original response to Pierre I wrote:
> 
>   A non-Registry example for harvest is GloTS, and that is already
>   following this proposal (or so I hope); but of course you're right,
>   other syncing activity should be somehow mentioned, too.  I'm
>   uncertain whether there's a point to tell these apart but I'm leaning
>   towards "probably not".
> 
>   If so, what you're asking for is a different term, right?  Trouble
>   is, I don't have a good one.  "m2m-transfer" ("machine to
>   machine")...?  Argl.
> 
> "mirror" as this other term I don't like too much, as I think it is a
> different use case than harvest.  I can't think of a major
> operational reason to tell them apart, though, so having an umbrella
> term for both would still seem reasonable.

"copy"?

--
Mark Taylor  Astronomical Programmer  Physics, Bristol University, UK
m.b.taylor at bristol.ac.uk          http://www.star.bristol.ac.uk/~mbt/