SNMP Exporter Generator

This is a custom built image used to automatically generate the snmp.yml file needed for the Prometheus SNMP exporter.
Unlike most containers, this does not process anything during runtime. Instead, all of the processing is performed during image creation.

I use this as an init-container for my Prometheus SNMP exporter deployment that resides on my Kubernetes cluster. It mounts the same persistent volume claim as the SNMP exporter, and copies the snmp.yml file. If the snmp.yml values change, it will be automatically picked up upon exporter rebuild.

Modifying the Contents of This Container

All supporting MIBs sit in the mibs directory, and the generator.yml sits in the root of the repository. The image build copies these to the appropriate location in the container. Upon push to Github, the built-in CI/CD will bake a new image and push to container registry under the tag ghcr.io/fred-drake/snmp-exporter-generator:latest.

Supporting architectures

Both arm64 and amd64 are supported. Note that at the time of this writing, the official prom/snmp-exporter image for configurator generation does not support arm64.

Init-Container Example

Below is my deployment, which illustrates how I use this image as an init-container, before the actual snmp-exporter container is built.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: snmp-exporter
  namespace: prometheus
spec:
  replicas: 1
  selector:
    matchLabels:
      app: snmp-exporter
  template:
    metadata:
      labels:
        app: snmp-exporter
    spec:
      volumes:
        - name: config
          emptyDir: {}
      containers:
      - name: snmp-exporter
        image: prom/snmp-exporter
        env:
        - name: TZ
          value: America/New_York
        volumeMounts:
        - name: config
          mountPath: /etc/snmp_exporter
        ports:
        - containerPort: 9116
          name: metrics
      initContainers:
      - name: init-config
        image: ghcr.io/fred-drake/snmp-exporter-generator
        imagePullPolicy: Always
        command:
          - sh
          - -c
          - cp -f /opt/snmp.yml /etc/snmp_exporter
        volumeMounts:
        - name: config
          mountPath: /etc/snmp_exporter

For completeness, below is my service definition.

# This gets called by Prometheus at http://snmp-exporter.prometheus.svc.cluster.local:9116
kind: Service
apiVersion: v1
metadata:
  name: snmp-exporter
  namespace: prometheus
spec:
  type: ClusterIP
  selector:
    app: snmp-exporter
  ports:
  - name: http-metrics
    port: 9116
    protocol: TCP
    targetPort: metrics