Updated JWT is lost after restarting D2CB instance

D2CB keeps updating JWT periodically in order to avoid getting it expire. This is generally updated once every 10 days, but the periodicity is configurable.

This works well as long as the D2CB instance keeps running. However, once it is restarted, the updated JWT is lost and we restart with the JWT that was packaged into the docker image. This can be fine, unless the docker image was created more than 30 days ago, then we get a broken instance that can not update itself.