Similarly to AWS cloud provider, GKE also supports using the L4 LoadBalancer for Kubernetes Services. Just specify Service.spec.type as the LoadBalancer, and then GKE will set up and configure the L4 LoadBalancer automatically.

Note that the corresponding firewall rule between the L4 LoadBalancer and the Kubernetes node can be created by the cloud provider automatically. This is simple but powerful enough if you want to quickly expose your application to the internet:

$ cat grafana.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: grafana
spec:
  replicas: 1
  selector:
    matchLabels:
      project: devops-with-kubernetes
      app: grafana
  template:
    metadata:
      labels:
        project: devops-with-kubernetes
        app: grafana
    spec:
     containers:
       - image: grafana/grafana
         name: grafana
         ports:
          - containerPort: 3000
---
apiVersion: v1
kind: Service
metadata:
  name: grafana
spec:
  ports:
    - port: 80
      targetPort: 3000
  type: LoadBalancer
  selector:
    project: devops-with-kubernetes
    app: grafana 

   
//deploy grafana with Load Balancer service
$ kubectl create -f grafana.yml 
deployment.apps "grafana" created
service "grafana" created

    
//check L4 Load balancer IP address
$ kubectl get svc grafana
NAME      TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)        AGE
grafana   LoadBalancer   10.59.244.97   35.243.118.88   80:31213/TCP   1m

   
//can reach via GCP L4 Load Balancer
$ curl -I 35.243.118.88
HTTP/1.1 302 Found
Content-Type: text/html; charset=utf-8
Location: /login
Set-Cookie: grafana_sess=186d81bd66d150d5; Path=/; HttpOnly
Set-Cookie: redirect_to=%252F; Path=/; HttpOnly
Date: Sun, 09 Dec 2018 02:25:48 GMT