if you want to do this with docker, login via
docker exec -it --workdir /root --user root <docker_name> bash
then go edit the following files with vi: /etc/grafana/grafana.ini /usr/share/grafana/conf/sample.ini /usr/share/grafana/conf/default.ini
in line 373, modify min_refresh_interval = 5s to 1 second, then restart the docker container
