Persistent data across multicontainers

[jason10]

I have used within a container the /data path for persistent data across reboots, eg logs. I know that this mount is associated with my container from the point of view of the host
balenaOS.

Now that I’m using a multicontainer solution, how do I exchange data that I want to persist between containers across reboots? Eg, container one captures frames from a camera and sends them to container two.

[dansku]

Hey @jason10,

You can achieve this by using something called named-volume.

Take a look at this docker-compose.yml file as reference:

shaunmulligan/multicontainer-tester/blob/master/docker-compose.yml#L36-43

You have a volume:

volumes:
  data-volume:

And on each container, you add - data-volume:/containers-shared

Hope this helps!
Cheers

[pdcastro]

Also worth having a look at the documentation for named volumes:

• https://www.balena.io/docs/learn/develop/multicontainer/#named-volumes
  (Includes some information relevant to upgrades from balenaOS versions older than 2.12.0.)
• https://docs.docker.com/storage/volumes/