[Fiware-tech-help] Questions regarding FIWARE setup (Orion, QL, CrateDB)

[Jakob Schnell]

Hey Federico,

thanks for your reply.
I am indeed referring to the tutorial you linked to.

Sorry for not clarifying this in my initial question - I noted that docker
volumes were being removed, so I commented out Lines 56 through 60 in the
services script. They are now not removed anymore, so the CrateDB-Data is still
available after a restart.

However, even after using
docker-compose down
docker-compose up
as you suggested, the created subscriptions don't exist anymore.

THus, all my initial questions remain:
* Can I persist subscriptions or do I have to recreate them on a system restart?
* Can I get QuantumLeap or Orion to return the data saved in the CrateDB after
  a restart?
* What exactly is the purpose of the MongoDB connected to Orion?
* What is the purpose of the Redis connected to QuantumLeap?

Best regards,
Jakob

On Wed, 9 Mar 2022 14:09:32 +0100
Federico Michele Facca <federico.facca at martel-innovate.com> wrote:

> Hi Jakob,
> I suppose you are referring to this tutorial:
> https://github.com/FIWARE/tutorials.Time-Series-Data
> 
> Looking at the docker compose, volumes are there, so data should be
> persisted, unless when when you
> stopped docker compose, you also removed the volumes (e.g. docker-compose
> down -v).
> 
> Which is exactly what the stoppingContainers() function of the services
> script does:
> https://github.com/FIWARE/tutorials.Time-Series-Data/blob/master/services#L50
> 
> As indeed also explained in the documentation:
> [image: image.png]
> 
> Bottomline, if you re-run the tutorial, but instead of cleaning up you just
> stop and restart the docker-compose stack,
> data will be there, e.g.
> 
> docker-compose down
> 
> docker-compose up
> 
> Cheers,
> 
> *Dr. FEDERICO MICHELE FACCA*
> *CTO, Head of Martel Lab*
> +41 788075838
> *MARTEL INNOVATE* <https://www.martel-innovate.com/> - INNOVATION, WE MAKE
> IT HAPPEN
> Click *HERE* to download Martel reports and white papers!
> <https://www.martel-innovate.com/premium-content/>
> Follow us on *TWITTER* <https://twitter.com/Martel_Innovate>
> 
> 
> On Wed, 9 Mar 2022 at 12:19, Jakob Schnell <Jakob.Schnell at heigit.org> wrote:
> 
> > Hey,
> >
> > I'm currently setting up a FIWARE backend using docker, following the
> > "Querying Time Series Data" tutorial. I am a bit confused by how the FIWARE
> > components are supposed to behave on a restart of the system.
> >
> > My setup consists of a Context Broker (Orion), QuantumLeap and a CrateDB
> > for
> > data persistence, and I have created subscriptions for possible incoming
> > data. Assume that some data has been entered and persisted into CrateDB.
> >
> > If I now restart the running docker containers, if I understood correctly,
> > Orion won't have any data anymore, the subscriptions will be gone and I
> > haven't
> > found a way to get QuantumLeap to query the CrateDB for the data entered.
> >
> > That would mean that I have to create all subscriptions anew and that I
> > have to
> > query CrateDB directly for any "historical" data, which makes the system
> > rather
> > clunky to use. All restarts would require manual interaction or some sort
> > of
> > automating the creation of subscriptions, and all advantages of NGSI-v2 are
> > lost if CrateDB has to be queried directly.
> >
> > Is there a way to persist subscriptions? Can I get QuantumLeap or Orion to
> > return the data saved in the CrateDB?
> >
> > On a related note, could you explain what the purpose of the MongoDB
> > connected
> > to Orion and the Redis connected to QuantumLeap is? Would the system work
> > without either of these?
> >
> > Thanks for your help,
> > Best regards,
> > Jakob Schnell
> >
> > --
> > Jakob Schnell
> > HeiGIT gGmbH
> > Heidelberg Institute for Geoinformation Technology at Heidelberg University
> >
> > https://heigit.org | jakob.schnell at heigit.org | phone +49-6221-533 482
> >
> > Postal address: Schloss-Wolfsbrunnenweg 33 | 69118 Heidelberg | Germany
> > Offices: Berliner Str. 45 | 69120 Heidelberg | Germany
> >
> > Amtsgericht Mannheim | HRB 733765
> > Managing Directors: Prof. Dr. Alexander Zipf | Dr. Gesa Schönberger
> >
> >
> >
> > __________________________________________________________________________________________
> >
> > You can get more information about our cookies and privacy policies on the
> > following links:
> > -
> > https://fiware-legal.readthedocs.io/en/latest/PersonalDataProtectionPolicy.html
> > - https://fiware-legal.readthedocs.io/en/latest/FIWARECookiesPolicy.html
> >
> >
> > fiware-tech-help mailing list
> > fiware-tech-help at lists.fiware.org
> >
> > To unsubscribe from fiware-tech-help mailing list, go to the information
> > page of the list at:
> > https://lists.fiware.org/listinfo/fiware-tech-help
> >
> >  



-- 
Jakob Schnell
HeiGIT gGmbH
Heidelberg Institute for Geoinformation Technology at Heidelberg University

https://heigit.org | jakob.schnell at heigit.org | phone +49-6221-533 482

Postal address: Schloss-Wolfsbrunnenweg 33 | 69118 Heidelberg | Germany
Offices: Berliner Str. 45 | 69120 Heidelberg | Germany

Amtsgericht Mannheim | HRB 733765
Managing Directors: Prof. Dr. Alexander Zipf | Dr. Gesa Schönberger