K
Q

Running simple hello world static http app in Kubernetes

4/17/2019

I have a simple Hello World app on Dockerhub and I'm trying to run it in Kubernetes but no luck, nothing shows up.

Dockerfile:

FROM centos:7

RUN  yum install httpd -y

RUN echo "Hello World" > /var/www/html/index.html

RUN chown -R apache:apache /var/www/html

EXPOSE 80

CMD  [ "/usr/sbin/httpd", "-D", "FOREGROUND" ]

Kubernetes YAML:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: ingress-test
  labels:
    app: hello-world
spec:
  replicas: 1
  selector:
    matchLabels:
      app: hello-world
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
      - name: helloworld
        image: 56789/world:v1
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: hello-world
spec:
  selector:
    app: hello-world
  ports:
  - protocol: "TCP"
    port: 80
    targetPort: 80
  type: LoadBalancer
-- Dilfuza Sakura
apache
docker
kubernetes

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1 Answer

4/17/2019

As you are running a simple hello world app, I assume you might use minikube & you are not doing this in the cloud.

Delete the service and create the service like this. Now you could be able to access your application http://<minikube-ip>:30080

apiVersion: v1
kind: Service
metadata:
  name: hello-world
spec:
  selector:
    app: hello-world
  ports:
  - protocol: "TCP"
    port: 80
    targetPort: 30080
  type: NodePort

LoadBalancer service is for cloud like AWS/Azure/Google cloud etc. So It can not create any LoadBalancer in your local minikube. There are workarounds to make it work by using externalIPs which you could find here - https://kubernetes.io/docs/concepts/services-networking/service/

To debug this issue, assuming pod is running and appropriate ports are open, create a ClusterIP service.

apiVersion: v1
kind: Service
metadata:
  name: hello-world
spec:
  selector:
    app: hello-world
  ports:
  - protocol: "TCP"
    port: 80
    targetPort: 80
  type: ClusterIP

Now first check if your application is accessible inside the cluster.

kubectl run busybox --image=busybox --restart=Never -it --rm -- wget -O- http://hello-world/

If it does not work, something is wrong the pod itself!

-- vins
Source: StackOverflow