kapacitor: missing documentation for backwards incompatible change to running kapacitor as non-root in v1.7.4

[andoks]

After upgrading the kapacitor docker image from v1.7.0 to v1.7.4 we started getting consistent errors during startup: run: open server: open service *storage.Service: open boltdb @ "/var/lib/kapacitor/kapacitor.db": open /var/lib/kapacitor/kapacitor.db: permission denied and kapacitor refused to start.

After some digging I found commit 4adc1da that changed the docker image to run kapacitor as a non-root user between v1.7.3 and v1.7.4, and the ability continue running kapacitor as root by setting KAPACITOR_AS_ROOT=true.

Should this perhaps be documented in the docs over at https://hub.docker.com/_/kapacitor?

[powersj]

Thanks for calling this out: docker-library/docs#2450