docker-promtool

Why?

Keeping your prometheus config files under source control is great for shared ownership of a monitoring system. But you want to use a CI/CD system to make sure that nobody breaks monitoring by pushing an invalid config file.

Prometheus has a nice utility called promtool which can be used to check that a config/rules file is valid. But to use it, you need to build it yourself, or run it from the base prom/prometheus docker image which isn't compatible with the drone.io CI system because it runs as a custom user inside the container.

We built this image to be lightweight, just alpine linux with the promtool binary, and nothing else.

About this repo

This repo just tracks changes to the Dockerfile. The built image can be found at https://hub.docker.com/r/dnanexus/promtool/

Usage

Using docker run

Check a prometheus config file:

docker run \
  -v /path/to/local/prometheus/configs:/tmp \
  dnanexus/promtool:2.9.2 \
  check config /tmp/prometheus.yml

Check a prometheus rules file

docker run \
  -v /path/to/local/prometheus/configs:/tmp \
  dnanexus/promtool:2.9.2 \
  check rules /tmp/prometheus.rules.yml

Using drone pipeline step

pipeline:
  validate:
    image: dnanexus/promtool:2.9.2
    commands:
      - promtool check rules prometheus.rules.yml
      - promtool check config prometheus.yml

Using wercker pipeline step

validate-prometheus-config:
  box:
    id: dnanexus/promtool:2.9.2
  steps:
  - script:
    name: Validate prometheus configuration rules (alerting rules)
    description: if this is failing prometheus will not be able to start, better fail fast
    code: |
      promtool check config prometheus.yml
      promtool check rules prometheus.rules.yml

Version History

• 2.9.2: Alignment with prometheus releases
• 1.0: Initial release