Documentation incomplete for Helm implementation

[mikelorant]

Documentation in the README is incomplete when it comes to adding this to an existing Prometheus cluster (deployed with Helm).

Following should be added:

server:
  extraVolumeMounts:
    - name: config-out
      mountPath: /etc/prometheus/config_out

  extraVolumes:
    - name: config-out
      emptyDir: {}

Without defining an extra volume to create, this volume cannot be shared between 2 containers in a pod. You also to need to mount this volume into the Prometheus server container.

Be aware this is related to the chart in the Prometheus community Helm chart repository.
https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus

[mikelorant]

I'd also like to add that additionalScrapeConfig is also meant to be extraScrapeConfigs

It is also necessary to rename containers to sidecarContainers.

This may be due to the Helm chart you used, however based on what seems the official chart, this is likely something that should be referenced.

[joshm91]

Hey Mike,

The documentation is tailored towards configuring the tool on a Helm installation of the kube-prometheus-stack chart, which (at least according to artifacthub.io) is a bit more popular than the base Prometheus Helm chart.

Realistically though, that part of the documentation was meant more of a point in the right direction rather than explicit instructions to integrate the tool for every possible way that Prometheus can be run.

[mikelorant]

That makes sense. I was just surprised that there was no volume defined, I assume now that is something they have as standard.

Feel free to close this issue, it may help someone else by them just being able to find these notes in the future.

[joshm91]

Yeah, that's fair enough. I'll leave it open for the time and I'll add a more general note to the README about what's actually required if you're using a different method of installation for Prometheus.