Today I learned how to update docker configs on stack deploy. Docker configs are immutable meaning when re-deploying a stack they can not be updated.
The way to update configs on re-deploys is to create a new one each time a docker stack deploy is triggered. And a good way to to that is to template the config name using a unique value like (current system time).
configs:
settings.yml:
name: settings-${SETTINGS_TIMESTAMP}.yml
file: foo.yml
And then running stack deploy.
SETTINGS_TIMESTAMP=$(date +%s) docker stack deploy...