One of my side projects is developing and maintaining an unofficial Prometheus Exporter for Rancher. It exposes metrics pertaining to Rancher-specific resources including, but not limited to managed clusters, Kubernetes versions, and more. Below shows an example dashboard based on these metrics.
Incidentally, if you are using Rancher, I’d love to hear your thoughts/feedback.
Previous CI workflow
The flowchart below outlines the existing process. Whilst automated, pushing directly to latest is bad practice.
To improve this. Several additional steps were added. First of which acquires the latest, versioned image of the exporter and saves it to the $GITHUB_OUTPUT environment
- name: Retrieve latest Docker image version
id: get_version
run: |
echo "image_version=$(curl -s "https://registry.hub.docker.com/v2/repositories/virtualthoughts/prometheus-rancher-exporter/tags/" | jq -r '.results[].name' | grep -v latest | sort -V | tail -n 1)" >> $GITHUB_OUTPUT
Referencing this, the next version can be generated based on MAJOR.MINOR.PATCH. Incrementing the PATCH version. In the future, this will be modified to add more flexibility to change MAJOR and MINOR versions.
- name: Increment version
id: increment_version
run: |
# Increment the retrieved version
echo "updated_version=$(echo "${{ steps.get_version.outputs.image_version }}" | awk -F. -v OFS=. '{$NF++;print}')" >> $GITHUB_OUTPUT
With the version generated, the subsequent step can tag and push both the incremented version, and latest.
- name: Build and push
uses: docker/build-push-action@v3
with:
context: .
push: true
tags: |
virtualthoughts/prometheus-rancher-exporter:${{ steps.increment_version.outputs.updated_version }}
virtualthoughts/prometheus-rancher-exporter:latest
Lastly, the Github action will also modify the YAML manifest file to reference the most recent, versioned image:
- name: Update Kubernetes YAML manifest
run: |
# Install yq
curl -sL https://github.com/mikefarah/yq/releases/latest/download/yq_linux_amd64 -o yq
chmod +x yq
sudo mv yq /usr/local/bin/
# Find and update the image tag in the YAML file
IMAGE_NAME="virtualthoughts/prometheus-rancher-exporter"
NEW_TAG="${{ steps.increment_version.outputs.updated_version }}"
OLD_TAG=$(yq eval '.spec.template.spec.containers[] | select(.name == "rancher-exporter").image' manifests/exporter.yaml | cut -d":" -f2)
NEW_IMAGE="${IMAGE_NAME}:${NEW_TAG}"
sed -i "s|${IMAGE_NAME}:${OLD_TAG}|${NEW_IMAGE}|" manifests/exporter.yaml
Which results in:
