[Create a Pod]
$ kubectl apply -f Pod_1.yaml
$ kubectl apply -f https://k8s.io/examples/pods/inject/envars.yaml

[List the running Pods]
$ kubectl get pods -l purpose=demonstrate-envars
NAME            READY     STATUS    RESTARTS   AGE
envar-demo      1/1       Running   0          9s

[List the Pod's container environment variables]
$ kubectl exec envar-demo -- printenv
NODE_VERSION=4.4.2
EXAMPLE_SERVICE_PORT_8080_TCP_ADDR=10.3.245.237
HOSTNAME=envar-demo
...
DEMO_GREETING=Hello from the environment
DEMO_FAREWELL=Such a sweet sorrow


[Playlist]
https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/
