Programmatically get the name of the pod that a container belongs to in Kubernetes?

Question

Is there a way to programmatically get the name of the pod that a container belongs to in Kubernetes? If so how? I'm using fabric8's java client but curl or something similar will be fine as well.

Note that I don't want to find the pod using a specific label since then (I assume) I may not always find the right pod if it's scaled with a replication controller.

Answer 1

You can tell Kubernetes to put the pod name in an environment variable of your choice using the downward API.

For example:

apiVersion: v1
kind: Pod
metadata:
  name: dapi-test-pod
spec:
  containers:
    - name: test-container
      image: gcr.io/google_containers/busybox
      command: [ "/bin/sh", "-c", "env" ]
      env:
        - name: MY_POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: MY_POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        - name: MY_POD_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP
  restartPolicy: Never

Answer 2

The pod name is written to /etc/hostname so it's possible to read it from there. In Java (which I'm using) you can also get the hostname (and thus the name of the pod) by calling System.getenv("HOSTNAME").