Discovering services from within your Pod

There are two means by which services are visible from within your Pods. The first is through environment variables that are added to all Pods in the same namespace as the service.

When you add a service (using kubectl create, or kubectl apply), the service is registered within Kubernetes and thereafter any Pods that are started will get environment variables set that reference the services. For example, if we created the preceding first example service, and then ran:

kubectl get services

We would see the service listed:

NAME            CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
flask           10.0.0.61    <none>        80/TCP    2d
kubernetes      10.0.0.1     <none>        443/TCP   5d

If you looked inside that container, you would see environment variables associated with both services listed previously. Those environment variables are:

env

KUBERNETES_PORT=tcp://10.0.0.1:443
KUBERNETES_SERVICE_PORT=443
KUBERNETES_PORT_443_TCP_ADDR=10.0.0.1...