Environment Variables

You can set environment variables for containers running in a pod and in addition, Kubernetes exposes certain runtime infos via environment variables automatically.

Let’s launch a pod that we pass an environment variable SIMPLE_SERVICE_VERSION with the value 1.0:

kubectl create -f https://raw.githubusercontent.com/mhausenblas/kbe/master/specs/envs/pod.yaml

kubectl describe pod envs | grep IP:

Now, let’s verify from within the cluster if the application running in the pod has picked up the environment variable SIMPLE_SERVICE_VERSION:

curl 172.17.0.3:9876/info

And indeed it has picked up the user-provided environment variable (the default, response would be "version": "0.5.0").

You can check what environment variables Kubernetes itself provides automatically (from within the cluster, using a dedicated endpoint that the app exposes):

curl 172.17.0.3:9876/env

Alternatively, you can also use kubectl exec to connect to the container and list the environment variables directly, there:

kubectl exec envs -- printenv

You can destroy the created pod with:

kubectl delete pod/envs

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