I just tried to enable the Prometheus metrics on /-/metrics as per https://docs.gitlab.com/ce/administration/monitoring/prometheus/gitlab_metrics.html.
I run Gitlab 9.5 from a Docker image. The settings has a check box to enable these metrics, but states that the “Environment variable prometheus_multiproc_dir does not exist or is not pointing to a valid directory.”.
I stopped, removed and restarted the Docker container using -e prometheus_multiproc_dir=/tmp - this seemed to have 0 effect; the warning persists. I tried a number of different directories; warning still persists. I logged in to the gitlab container and echo’d out $prometheus_multiproc_dir and it shows the directory I set. The environment variable is definitely there.
When I access /-/metrics, I get a 404. This might be because nothing is running to provide the metrics as even with the checkbox on, it seems to do nothing as long as this warning persists.
What am I missing here? How am I supposed to set this environment variable? I also tried to set it in gitlab_rails[‘prometheus_multiproc_dir’] - also to no avail.