Mastering Kubernetes - Second Edition

Consuming a ConfigMap as an environment variable

When you are creating a pod, you can specify a ConfigMap and consume its values in several ways. Here is how to consume our configuration map as an environment variable:

apiVersion: v1 
kind: Pod 
metadata: 
  name: some-pod 
spec: 
  containers: 
    - name: some-container 
      image: busybox 
      command: [ "/bin/sh", "-c", "env" ] 
      env: 
        - name: DB_IP_ADDRESSES 
          valueFrom: 
            configMapKeyRef: 
              name: db-config 
              key: db-ip-addresses         
  restartPolicy: Never 

This pod runs the busybox minimal container and executes an env bash command and immediately exists. The db-ip-addresses key from the db-config map is mapped to the DB_IP_ADDRESSES environment variable, and is reflected in the output:

> kubectl logs some-pod
HUE_REMINDERS_SERVICE_PORT=80 ...