Configmap

A ConfigMap is an API object used to store non-confidential data in key-value pairs. Pods can consume ConfigMaps as environment variables, command-line arguments, or as configuration files in a volume.

A ConfigMap allows you to decouple environment-specific configuration from your container images, so that your applications are easily portable.

Caution: ConfigMap does not provide secrecy or encryption. If the data you want to store are confidential, use a Secret rather than a ConfigMap, or use additional (third party) tools to keep your data private.

Configmap

kind: ConfigMap 
apiVersion: v1 
metadata:
  name: example-configmap 
data:
  # Configuration values can be set as key-value properties
  database: mongodb
  database_uri: mongodb://localhost:27017
  
  # Or set as complete file contents (even JSON!)
  keys: | 
    image.public.key=771 
    rsa.public.key=42

Pod

kind: Pod 
apiVersion: v1 
metadata:
  name: pod-env-var 
spec:
  containers:
    - name: env-var-configmap
      image: nginx:1.7.9 
      envFrom:
        - configMapRef:
            name: example-configmap