K
Q

How to use NodePort with kind?

6/17/2020

I'm trying to use NodePort with kind but somehow it doesn't want to work.

I've successfully deployed the following cluster:

apiVersion: kind.x-k8s.io/v1alpha4
kind: Cluster
nodes:
- role: control-plane
  extraPortMappings:
  - containerPort: 80
    hostPort: 30000
    listenAddress: "0.0.0.0" # Optional, defaults to "0.0.0.0"
    protocol: tcp # Optional, defaults to tcp
- role: worker

and then a very simple deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hostname-deployment
  labels:
    app: hostname
spec:
  replicas: 2
  selector:
    matchLabels:
      app: hostname
  template:
    metadata:
      labels:
        app: hostname
    spec:
      containers:
      - name: hostname
        image: hostname:0.1
        ports:
        - containerPort: 80

and a service:

apiVersion: v1
kind: Service
metadata:
  name: hostname-service
spec:
  type: NodePort
  selector:
    app: hostname
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
      nodePort: 30000

and I can connect to the service via e.g.

(in one terminal)
k port-forward service/hostname-service 8080:80
Forwarding from 127.0.0.1:8080 -> 80

(another one)
curl localhost:8080
hostname: hostname-deployment-75c9fd6584-ddc59 at Wed, 17 Jun 2020 15:38:33 UTC

But I cannot connect to the service via the exposed NodePort

curl -v localhost:30000
* Rebuilt URL to: localhost:30000/
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 30000 (#0)
> GET / HTTP/1.1
> Host: localhost:30000
> User-Agent: curl/7.58.0
> Accept: */*
>
* Recv failure: Connection reset by peer
* stopped the pause stream!
* Closing connection 0
curl: (56) Recv failure: Connection reset by peer

kubectl get all output:

NAME                                       READY   STATUS    RESTARTS   AGE
pod/hostname-deployment-75c9fd6584-ddc59   1/1     Running   0          34m
pod/hostname-deployment-75c9fd6584-tg8db   1/1     Running   0          34m

NAME                       TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
service/hostname-service   NodePort    10.107.104.231   <none>        80:30000/TCP   34m
service/kubernetes         ClusterIP   10.96.0.1        <none>        443/TCP        35m

NAME                                  READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/hostname-deployment   2/2     2            2           34m

NAME                                             DESIRED   CURRENT   READY   AGE
replicaset.apps/hostname-deployment-75c9fd6584   2         2         2       34m
-- Patryk
docker
kind
kubernetes
port

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6 Answers

6/17/2020

I would try removing the nodePort: 30000 and check that the newly assigned nodePort works with the loopback interface. If you do an update of the service, kube has a problem with satically asigned nodePorts, you have to manige yourself the port collision. Trying to delete the deployment and redeploy could also help.

-- Armando Ballaci
Source: StackOverflow
9/1/2021

in the kind config yaml

containerPort must be the same with the 'NodePort' in service config. in your case is 30000

tips: hostPort can be any port ,it does not need to be the same with containerPort

-- Eric Huang
Source: StackOverflow
1/5/2022

You shouldn't use nodeport with local IP. Instead you should: 1. use command : kubectl get nodes -o wide 2. note down the IP of the node 3. curl <node-ip>:30000

or

  1. docker exec -it <NodeName> /bin/bash

  2. curl localhost:30000

-- Stan Peng
Source: StackOverflow
6/17/2020

Kind cluster configuration needs to be like below

apiVersion: kind.x-k8s.io/v1alpha4
kind: Cluster
nodes:
- role: control-plane
  extraPortMappings:
  - containerPort: 30000
    hostPort: 30000
    listenAddress: "0.0.0.0" # Optional, defaults to "0.0.0.0"
    protocol: tcp # Optional, defaults to tcp
- role: worker

This file is then passed to your creation command as kind create cluster --config=config.yaml (according to docs).

-- Arghya Sadhu
Source: StackOverflow
6/17/2020

Actually doing what Arghya Sadhu suggested worked. Not sure why the answer got deleted.

apiVersion: kind.x-k8s.io/v1alpha4
kind: Cluster
nodes:
- role: control-plane
  extraPortMappings:
  - containerPort: 30000
    hostPort: 30000
    listenAddress: "0.0.0.0"
    protocol: tcp
- role: worker
-- Patryk
Source: StackOverflow
6/2/2021

I will share my answer as i tried out this today by using multi node kind cluster and another important thing is that needs to take care about kubectl client and server versions. I believe this will help someone.

Step 1

kind-api-cluster.yml

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  extraPortMappings:
  - containerPort: 30950
    hostPort: 30950
    listenAddress: "127.0.0.1"
    protocol: TCP
- role: worker
- role: worker

Step 2 Kubernetes service and deployment file. ( If you note here, the kind's control-plane hostPort and kubernetes service's nodePort should be the same )

api.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api
  labels:
    app: api
spec:
  replicas: 3
  selector:
    matchLabels:
      app: api
  template:
    metadata:
      labels:
        app: api
    spec:
      containers:
        - name: api
          image: api
          imagePullPolicy: Never
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: api-svc
spec:
  selector:
    app: api
  type: NodePort
  ports:
    - name: http
      nodePort: 30950
      targetPort: 8080
      port: 8080

Additional Notes:-

kubectl version

Client Version: version.Info{Major:"1", Minor:"20+", GitVersion:"v1.20.4-dirty", GitCommit:"e87da0bd6e03ec3fea7933c4b5263d151aafd07c", GitTreeState:"dirty", BuildDate:"2021-03-15T09:55:27Z", GoVersion:"go1.16.2", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"20", GitVersion:"v1.20.2", GitCommit:"faecb196815e248d3ecfb03c680a4507229c2a56", GitTreeState:"clean", BuildDate:"2021-01-21T01:11:42Z", GoVersion:"go1.15.5", Compiler:"gc", Platform:"linux/amd64"}

kind --version

kind version 0.10.0
-- sujithramanathan
Source: StackOverflow