kompose not exposing NodePort - Docker for Desktop Windows - docker

Question

I have this docker-compose.yml and Docker for Desktop Windows with a local kubernetes cluster (the default docker-desktop context) running:
version: '3'
services:
web:
image: customnode
ports:
- "3000:3000"
labels:
kompose.service.type: nodeport
datastore:
image: custommongo
ports:
- "27017:27017"
docker-compose up -d works perfectly and exposes my NodeJS on port 3000 on 127.0.0.1.
I'm trying to migrate that the my k8s cluster, so following https://kompose.io/getting-started/
Page above says "If you don’t already have a Kubernetes cluster running, minikube is the best way to get started"... I am already running the OOTB Docker for Desktop cluster so I assume I don't need minikube.
kompose convert
INFO Kubernetes file "datastore-service.yaml" created
INFO Kubernetes file "web-service.yaml" created
INFO Kubernetes file "datastore-deployment.yaml" created
INFO Kubernetes file "web-deployment.yaml" created
Here are the web-deployment and web-service YAMLS:
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
annotations:
kompose.cmd: kompose convert
kompose.service.type: nodeport
kompose.version: 1.16.0 (0c01309)
creationTimestamp: null
labels:
io.kompose.service: web
name: web
spec:
replicas: 1
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
io.kompose.service: web
spec:
containers:
image: customnode
name: web
ports:
- containerPort: 3000
resources: {}
restartPolicy: Always
status: {}
apiVersion: v1
kind: Service
metadata:
annotations:
kompose.cmd: kompose convert
kompose.service.type: nodeport
kompose.version: 1.16.0 (0c01309)
creationTimestamp: null
labels:
io.kompose.service: web
name: web
spec:
ports:
- name: "3000"
port: 3000
targetPort: 3000
selector:
io.kompose.service: web
type: NodePort
status:
loadBalancer: {}
Finally, running kompose up:
kompose up
[36mINFO[0m We are going to create Kubernetes Deployments, Services and PersistentVolumeClaims for your Dockerized application. If you need different kind of resources, use the 'kompose convert' and 'kubectl create -f' commands instead.
INFO Deploying application in "default" namespace
INFO Successfully created Service: datastore
INFO Successfully created Service: web
INFO Successfully created Deployment: datastore
INFO Successfully created Deployment: web
Output of kubectl get svc:
kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
datastore ClusterIP 10.103.***.*** <none> 27017/TCP 76s
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 23m
web NodePort 10.106.***.*** <none> 3000:32033/TCP 76s
As you can see, no external IP as I'd expect. I'm sure this is a lack of knowledge on my part, rather than a bug, so what am I missing?

Answer 1

Extenal IP is assigned only for LoadBalancer type service. A LoadBalancer controller must be installed on the cluster for LoadBalancer service to work. Else LoadBalancer service behaves exactly as a NodePort service. Most cloud providers have support for LoadBalancer services.
For NodePort type services, the service binds to a random port in node port range on all the nodes. In your case you can see, the service is bound to port 32033 - 3000:32033/TCP.
The Node Port range is configured for as an argument to Kubernetes API server with the option --service-node-port-range (by default 30000-32767). When you create a NodePort type service, a random free port is picked from this range. If you want to choose a custom port, you can specify nodePort attribute in the Port object.
Eg:
apiVersion: v1
kind: Service
metadata:
annotations:
kompose.cmd: kompose convert
kompose.service.type: nodeport
kompose.version: 1.16.0 (0c01309)
creationTimestamp: null
labels:
io.kompose.service: web
name: web
spec:
ports:
- name: "3000"
port: 3000
targetPort: 3000
nodePort: 30002 ###### You can choose node port here if needed
selector:
io.kompose.service: web
type: NodePort ####### Change this line to LoadBalancer if you want an external IP
status:
loadBalancer: {}