kubernetes dns list all ips for service - kubernetes

Question

I have a list of pods like so:
❯ kubectl get pods -l app=test-pod (base)
NAME READY STATUS RESTARTS AGE
test-deployment-674667c867-jhvg4 1/1 Running 0 14m
test-deployment-674667c867-ssx6h 1/1 Running 0 14m
test-deployment-674667c867-t4crn 1/1 Running 0 14m
I have a service
kubectl get services (base)
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default test-service ClusterIP 10.100.4.138 <none> 4000/TCP 15m
I perform a dns query:
❯ kubectl exec -ti test-deployment-674667c867-jhvg4 -- /bin/bash (base)
root#test-deployment-674667c867-jhvg4:/# busybox nslookup test-service
Server: 10.100.0.10
Address: 10.100.0.10:53
Name: test-service.default.svc.cluster.local
Address: 10.100.4.138
My config:
apiVersion: apps/v1
kind: Deployment
metadata:
name: test-deployment
spec:
replicas: 3
selector:
matchLabels:
app: test-pod
template:
metadata:
labels:
app: test-pod
spec:
containers:
- name: python-http-server
image: python:2.7
command: ["/bin/bash"]
args: ["-c", "echo \" Hello from $(hostname)\" > index.html; python -m SimpleHTTPServer 80"]
ports:
- name: http
containerPort: 80
kind: Service
apiVersion: v1
metadata:
name: test-service
spec:
selector:
app: test-pod
ports:
- protocol: TCP
port: 4000
targetPort: http
How can I instead get a list of all the pods's ip addresses via a dns query?
Ideally I would like to perform an nslookup of a name and get a list of all the pod's ips in a list.

Answer 1

You have to use a headless service with selectors. It returns the ip addresses of the pods.
See here:
https://kubernetes.io/docs/concepts/services-networking/service/#headless-services
.spec.clusterIP must be "None"