Different grafana.ini based on environment when deploying with helm

Question

I am deploying grafana to kubernetes using a custom helm chart. A custom grafana.ini file is copied to the docker image when it is built, the grafana.ini file contains the RDS instance connection config and various custom auth settings. This is not ideal when I bring more than one environment into the mix, as each build will require a different grafana.ini file, and I want to use the same base docker image. It's also not secure.

I have three kubernetes clusters, dev, preprod and prod. The crucial differences will be the RDS configuration.

What is the best way of binding a grafana.ini file to a certain build of grafana, based on the environment. Can I use some kind of parametised configMap?

I am using helmfile to deploy the helm chart, so I am familiar with the concept of having seperate values.yaml files for each environment and setting an environment variable to target the right one.

Answer 1

You can mount a configmap as volume in the pod.

An example:

apiVersion: v1
kind: ConfigMap
metadata:
  creationTimestamp: null
  labels:
    env: prod
    app: metis
    client: ueuropea
  name: metis-clients-configmap
data:
  clients_db_config.yaml: |
    default-tenant:
      DB_HOST: dbhost
      DB_USERNAME: user
      DB_PASSWORD: pass
      DB_NAME: dbname
      DB_PORT: 3306

Deployment:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    env: dev
    app: metis
  name: metis-rules-evaluator-dev
spec:
  progressDeadlineSeconds: 3600
  replicas: 0
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
  template:
    metadata:
      labels:
        env: dev
        app: metis
        client: ueuropea
        mode: rules-evaluator
    spec:

      containers:
        - image: metis
          name: metis
          imagePullPolicy: Always
          resources: 
            requests:
              memory: "1024Mi"
              cpu: "3000m"
            limits:
              memory: "16384Mi"
              cpu: "4000m"
          volumeMounts:
            - name: config-vol
              mountPath: /usr/src/metis/config/
      volumes:
        - name: config-vol
          configMap:
            name: metis-clients-configmap
      terminationGracePeriodSeconds: 150
      restartPolicy: Always

In this example the configmap data will be mounted on path: /usr/src/metis/config/ and will create the file clients_db_config.yaml which can also be a .ini