This page shows how to create a Kubernetes Service object that exposes an external IP address.
kubectl
to communicate with your Kubernetes API server. For instructions, see the documentation for your cloud provider.Run a Hello World application in your cluster:
service/load-balancer-example.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app.kubernetes.io/name: load-balancer-example
name: hello-world
spec:
replicas: 5
selector:
matchLabels:
app.kubernetes.io/name: load-balancer-example
template:
metadata:
labels:
app.kubernetes.io/name: load-balancer-example
spec:
containers:
- image: gcr.io/google-samples/node-hello:1.0
name: hello-world
ports:
- containerPort: 8080
kubectl apply -f https://k8s.io/examples/service/load-balancer-example.yaml
The preceding command creates a Deployment and an associated ReplicaSet. The ReplicaSet has five Pods each of which runs the Hello World application.
Display information about the Deployment:
kubectl get deployments hello-world
kubectl describe deployments hello-world
Display information about your ReplicaSet objects:
kubectl get replicasets
kubectl describe replicasets
Create a Service object that exposes the deployment:
kubectl expose deployment hello-world --type=LoadBalancer --name=my-service
Display information about the Service:
kubectl get services my-service
The output is similar to:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
my-service LoadBalancer 10.3.245.137 104.198.205.71 8080/TCP 54s
type=LoadBalancer
service is backed by external cloud providers, which is not covered in this example, please refer to this page for the details. Display detailed information about the Service:
kubectl describe services my-service
The output is similar to:
Name: my-service
Namespace: default
Labels: app.kubernetes.io/name=load-balancer-example
Annotations: <none>
Selector: app.kubernetes.io/name=load-balancer-example
Type: LoadBalancer
IP: 10.3.245.137
LoadBalancer Ingress: 104.198.205.71
Port: <unset> 8080/TCP
NodePort: <unset> 32377/TCP
Endpoints: 10.0.0.6:8080,10.0.1.6:8080,10.0.1.7:8080 + 2 more...
Session Affinity: None
Events: <none>
Make a note of the external IP address (LoadBalancer Ingress
) exposed by your service. In this example, the external IP address is 104.198.205.71. Also note the value of Port
and NodePort
. In this example, the Port
is 8080 and the NodePort
is 32377.
In the preceding output, you can see that the service has several endpoints: 10.0.0.6:8080,10.0.1.6:8080,10.0.1.7:8080 + 2 more. These are internal addresses of the pods that are running the Hello World application. To verify these are pod addresses, enter this command:
kubectl get pods --output=wide
The output is similar to:
NAME ... IP NODE
hello-world-2895499144-1jaz9 ... 10.0.1.6 gke-cluster-1-default-pool-e0b8d269-1afc
hello-world-2895499144-2e5uh ... 10.0.1.8 gke-cluster-1-default-pool-e0b8d269-1afc
hello-world-2895499144-9m4h1 ... 10.0.0.6 gke-cluster-1-default-pool-e0b8d269-5v7a
hello-world-2895499144-o4z13 ... 10.0.1.7 gke-cluster-1-default-pool-e0b8d269-1afc
hello-world-2895499144-segjf ... 10.0.2.5 gke-cluster-1-default-pool-e0b8d269-cpuc
Use the external IP address (LoadBalancer Ingress
) to access the Hello World application:
curl http://<external-ip>:<port>
where <external-ip>
is the external IP address (LoadBalancer Ingress
) of your Service, and <port>
is the value of Port
in your Service description. If you are using minikube, typing minikube service my-service
will automatically open the Hello World application in a browser.
The response to a successful request is a hello message:
Hello Kubernetes!
To delete the Service, enter this command:
kubectl delete services my-service
To delete the Deployment, the ReplicaSet, and the Pods that are running the Hello World application, enter this command:
kubectl delete deployment hello-world
Learn more about connecting applications with services.
© 2022 The Kubernetes Authors
Documentation Distributed under CC BY 4.0.
https://kubernetes.io/docs/tutorials/stateless-application/expose-external-ip-address/