Relevant Documentation

• ConfigMaps
• 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