From what I have read, It seems that BALENA_SUPERVISOR_KEY should be generated when a container starts provided the io.balena.features.supervisor-api is set in the docker-file:
Here is an excerpt of the docker-compose.yml file:
When I try to run curl as in the example it fails due to the variable not being set, here I am trying to dereference the variable which appears to be empty…
If you’ve set the io.balena.features.supervisor-api indeed you should be able to get the key for your multicontainer app. Just to confirm, you’ve set that for each service that you are going to need it for right?
Can you share support access to your device? Once you have shared it, can you share the device UUID
Turns out it works as expected. I must have gotten myself out of sync. I most likely did not properly restart the appropriate container while updating the docker-compose.yml file.