k8s configmap example

configmap-test.yml

---
kind: ConfigMap 
apiVersion: v1 
metadata:
  name: example-configmap 
data:
  # Configuration values can be set as key-value properties
  # use '|' bar to add new line to each line, otherwise its missed out
  database: |
    mongodb
  database_uri: |
    mongodb://localhost:27017
  
  # Or set as complete file contents (even JSON!)
  keys: | 
    image.public.key=771 
    rsa.public.key=42
    some.other.key=123

---
kind: Pod 
apiVersion: v1 
metadata:
  name: pod-using-configmap 

spec:
  # Add the ConfigMap as a volume to the Pod
  volumes:
    # `name` here must match the name
    # specified in the volume mount
    - name: example-configmap-volume
      # Populate the volume with config map data
      configMap:
        # `name` here must match the name 
        # specified in the ConfigMap's YAML 
        name: example-configmap

  containers:
    - name: container-configmap
      image: alpine
      # keep the container up - so we can login to it
      command: ["sh", "-c", "tail -f /dev/null"]
      # Mount the volume that contains the configuration data 
      # into your container filesystem
      volumeMounts:
        # `name` here must match the name
        # from the volumes section of this pod
        - name: example-configmap-volume
        # this is where the config files are created in the container
          mountPath: /etc/config

# now you can exec into the container and look at the files
# microk8s.kubectl exec -it pod-using-configmap sh
#/ # cd /etc/config/
#/etc/config # cat keys 
#image.public.key=771 
#rsa.public.key=42
#some.other.key=123

# this is an updated version of https://itnext.io/learn-how-to-configure-your-kubernetes-apps-using-the-configmap-object-d8f30f99abeb