After you create a LoadBalancer service, you can access the service by using a Server Load Balancer (SLB) instance. For access requests from outside the cluster, you can use the domain name of the SLB instance and the service port, or use the IP address of the SLB instance and the service port. For access requests from within the cluster, you can use the service name and the service port. This topic describes how to access services by using SLB instances.

Prerequisites

You have read the considerations described in Considerations for configuring a LoadBalancer service.

Background information

Assume that the Cloud Controller Manager (CCM) version of your cluster is 1.9.3 or later, and you have specified an existing SLB instance for a service. By default, CCM does not configure listeners for the SLB instance. You can use the annotation service.beta.kubernetes.io/alibaba-cloud-loadbalancer-force-override-listeners: "true" to enable CCM to configure listeners for the SLB instance. You can also manually configure listeners for the SLB instance.

You can use the following methods to view the CCM version:
  • View the CCM version in the Container Service for Kubernetes (ACK) console.
    1. Log on to the the ACK console.
    2. In the left-side navigation pane, click Clusters.
    3. On the Clusters page, find the specific cluster, and choose More > Manage System Components in the Actions column of the cluster. The Core Components tab appears on the Add-ons page. You can view the CCM version on the Core Components tab.
  • Run the following command to query the CCM version. This method is applicable to dedicated clusters only. 
    kubectl get pod -n kube-system -o yaml|grep image:|grep cloud-con|uniq

Use the command-line tool

Method 1:

  1. Use kubectl to create an NGINX service.
    • Create an NGINX service.
      kubectl run nginx --image=registry.aliyuncs.com/acs/netdia:latest
    • Query the pod information.
      kubectl get pod
      NAME                                   READY     STATUS    RESTARTS   AGE
nginx-2721357637-dvwq3                 1/1       Running   1          6s
  2. Set the type of NGINX service to LoadBalancer. This allows you to access the service by using an SLB instance over the Internet.
    • Set the type of NGINX service to LoadBalancer.
      kubectl expose deployment nginx --port=80 --target-port=80 --type=LoadBalancer
    • Query the service information.
      kubectl get svc
      NAME                  CLUSTER-IP      EXTERNAL-IP      PORT(S)                        AGE
nginx                 172.19.XX.XX    101.37.XX.XX     80:31891/TCP                   4s
  3. Enter http://101.37.XX.XX in a browser to access the service.

Method 2:

  1. Write the following content to the nginx-svc.yml file.
    apiVersion: v1
kind: Service
metadata:
  labels:
    run: nignx
  name: nginx-01
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: nginx
  type: LoadBalancer
  2. Run the following command to create an NGINX service of the LoadBalancer type:
    kubectl apply -f nginx-svc.yml
  3. Run the following command to obtain the public IP address of the service:
    kubectl get service
    NAME           TYPE           CLUSTER-IP      EXTERNAL-IP      PORT(S)        AGE9d
ngi-01nx       LoadBalancer   172.19.XX.XX    101.37.XX.XX     80:32325/TCP   3h
  4. Copy http://101.37.XX.XX into the address bar of your browser and press the Enter key to access the NGINX service.

Use the Dashboard module in the ACK console

  1. Write the following content to the nginx-svc.yml file.
    apiVersion: v1
kind: Service
metadata:
  labels:
    run: nginx
  name: http-svc
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: nginx
  type: LoadBalancer
  2. Log on to the ACK console.
  3. In the left-side navigation pane, click Clusters.
  4. On the Clusters page, find the specific cluster, and choose More > Dashboardin the Actions column of the cluster.
  5. Click CREATE to create a service.
    Create a service
  6. Click the CREATE FROM FILE tab. Select the nginx-svc.yml file.
  7. Click UPLOAD.
    After the file is uploaded, an NGINX service of the LoadBalancer type and an SLB instance is created. The service name is http-svc.
  8. In the left-side navigation pane, select the default namespace. On the Overview page, you can view services in the default namespace in the Services section.
    You can find the newly created http-svc service. The external endpoint is 114.55.XX.XX:80.
  9. Enter http://114.55.XX.XX:80 in a browser to access the service.

Use the ACK console

  1. Log on to the ACK console.
  2. In the left-side navigation pane, click Clusters.
  3. On the Clusters page, click the name of a cluster or click Details in the Actions column. The details page of the cluster appears.
  4. In the left-side navigation pane, click Workload.
  5. On the Deployments tab, click Create from Template.
  6. Select Custom in Sample Template, and copy the following content to the Template section:
    apiVersion: v1
kind: Service
metadata:
  labels:
    run: nginx
  name: ngnix
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: nginx
  type: LoadBalancer
  7. Click CREATE.

    In the left-side navigation pane, click Services, and select the specific namespace from the namespace drop-down list to view the services deployed in the namespace.

References

Alibaba Cloud SLB supports a variety of features. For example, you can configure the health check, billing method, and instance type of an SLB instance by setting parameters. For more information, see Use annotations to configure SLB instances.