Add namespace to kubernetes hostname - kubernetes

Question

Currently my pods are all named "some-deployment-foo-bar" which does not help me track down issues when an error is reported with just the hostname.
So I want "$POD_NAMESPACE.$POD_NAME" as hostname.
I tried pod.beta.kubernetes.io/hostname: "foo" but that only sets an absolute name ... and subdomain did not work ...
The only other solution I saw was using a wrapper script that modifies the hostname and then executes the actual command ... which is pretty hacky and adds overhead ot every container.
Any way of doing this nicely?
current config is:
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: foo
labels:
project: foo
spec:
selector:
matchLabels:
project: foo
template:
metadata:
name: foo
labels:
project: foo
spec:
containers:
- image: busybox
name: foo

Answer 1

PodSpec has a subdomain field, which can be used to specify the Pod’s subdomain. This field value takes precedence over the pod.beta.kubernetes.io/subdomain annotation value.
There is more information here, below is an example.
apiVersion: v1
kind: Service
metadata:
name: default-subdomain
spec:
selector:
name: busybox
clusterIP: None
ports:
- name: foo # Actually, no port is needed.
port: 1234
targetPort: 1234
---
apiVersion: v1
kind: Pod
metadata:
name: busybox1
labels:
name: busybox
spec:
hostname: busybox-1
subdomain: default-subdomain
containers:
- image: busybox
command:
- sleep
- "3600"
name: busybox
---
apiVersion: v1
kind: Pod
metadata:
name: busybox2
labels:
name: busybox
spec:
hostname: busybox-2
subdomain: default-subdomain
containers:
- image: busybox
command:
- sleep
- "3600"
name: busybox