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

[Federico Michele Facca]

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
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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
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