ConfigMap & Secrets

Lesson Reference

1. Create a ConfigMap.

vi my-configmap.yml

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-configmap
data:
  key1: Hello, world!
  key2: |
    Test
    multiple lines
    more lines

kubectl create -f my-configmap.yml

2. View your ConfigMap data.

kubectl describe configmap my-configmap

3. Create a secret.
Get two base64-encoded values.

printf 'secret' | base64
printf 'anothersecret' | base64

vi my-secret.yml

Include your two base64-encoded values in the file.

apiVersion: v1
kind: Secret
metadata:
  name: my-secret
  type: Opaque
data:
  secretkey1: <base64 String 1>
  secretkey2: <base64 String 2>

kubectl create -f my-secret.yml

4. Create a pod and supply configuration data using environment variables.

vi env-pod.yml

apiVersion: v1
kind: Pod
metadata:
  name: env-pod
spec:
  containers:
  - name: busybox
    image: busybox
    command: ['sh', '-c', 'echo "configmap: $CONFIGMAPVAR secret: $SECRETVAR"']
    env:
    - name: CONFIGMAPVAR
      valueFrom:
        configMapKeyRef:
          name: my-configmap
          key: key1
    - name: SECRETVAR
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: secretkey1

kubectl create -f env-pod.yml

5. Check the log for the pod to see your configuration values!

kubectl logs env-pod

6. Create a pod and supply configuration data using volumes.

vi volume-pod.yml

apiVersion: v1
kind: Pod
metadata:
  name: volume-pod
spec:
  containers:
  - name: busybox
    image: busybox
    command: ['sh', '-c', 'while true; do sleep 3600; done']
    volumeMounts:
    - name: configmap-volume
      mountPath: /etc/config/configmap
    - name: secret-volume
      mountPath: /etc/config/secret
  volumes:
  - name: configmap-volume
    configMap:
      name: my-configmap
  - name: secret-volume
    secret:
      secretName: my-secret

kubectl create -f volume-pod.yml

7. Use kubectl exec to navigate inside the pod and see your mounted config data files.

kubectl exec volume-pod -- ls /etc/config/configmap
kubectl exec volume-pod -- cat /etc/config/configmap/key1
kubectl exec volume-pod -- cat /etc/config/configmap/key2
kubectl exec volume-pod -- ls /etc/config/secret
kubectl exec volume-pod -- cat /etc/config/secret/secretkey1
kubectl exec volume-pod -- cat /etc/config/secret/secretkey2