Container Compute Service:Expose an application using a Service

Method 1: Create a service using the console

1. Log on to the ACS console. In the left navigation pane, click Clusters.

2. On the Clusters page, click the name of the target cluster. In the left navigation pane, choose Network > Services.

3. On the Services page, click Create. In the Create Service dialog box, configure the parameters for the service.

   Parameter	Description	Example
   Name	The name of the service.	my-nginx-svc
   Service Type	The access method for the service. The following types are available: Cluster IP: Exposes the service on a cluster-internal IP address. The service is accessible only from within the cluster. Note When you select Cluster IP, you can configure a Headless Service. You can use a Headless Service to integrate with other service discovery mechanisms without being tied to the Kubernetes implementation. Server Load Balancer: Uses an Alibaba Cloud Classic Load Balancer (CLB) instance to expose the service. You can select Public Access or Internal Access. The CLB routes traffic to the service's ClusterIP. Create Resource: If you select Pay-by-specification, you can click Change Specification to modify the CLB specification. Use Existing Resource: You can select an existing CLB instance from the list. Note Using an existing CLB instance overwrites its existing listeners. CLB instances created by a service cannot be reused and can be accidentally deleted. Only CLB instances that you create manually in the console or by calling an API can be reused. If multiple services reuse the same CLB instance, ensure that their frontend listener ports are different to avoid port conflicts. SLB instances cannot be reused across clusters.	Create Service: Service Type: LoadBalancer SLB Type: Classic Load Balancer (CLB) Select Resource: Create Resource Create CLB Resource: Access Method: internal access Use the default values for other settings.
   Backend	The backend application that receives traffic from the service. If you do not select a backend, Kubernetes does not create a corresponding Endpoints object. For more information, see Services without selectors.	Name: app Value: nginx
   Port Mapping	Add a service port (the port field in the service YAML) and a container port (the targetPort field in the service YAML). The container port must match the port exposed by the backend Pods.	Service Port: 80 Container Port: 80 Protocol: TCP
   Annotations	Add an annotation to configure the ClusterIP or LoadBalancer resources for the service. Note Alibaba Cloud-specific annotations take effect only when the Service Type is set to Server Load Balancer. For example, the annotation service.beta.kubernetes.io/alicloud-loadbalancer-bandwidth:2 sets the peak bandwidth of the service to 2 Mbit/s to control traffic. For a full list of annotations, see Configure a Classic Load Balancer (CLB) by using annotations.	None
   Label	Add a label to identify the service.	None

   After configuring the parameters, click OK.

4. After the service is created, you can find the new service named my-nginx-svc on the Services page.

Method 2: Create a service using kubectl

1. Connect to your Kubernetes cluster using kubectl in CloudShell.

2. Create a file named my-nginx-svc.yaml with the following content.

   View my-nginx-svc.yaml

   apiVersion: v1
   kind: Service
   metadata:
     annotations:
       service.beta.kubernetes.io/alibaba-cloud-loadbalancer-address-type: "intranet"
     labels:
       app: nginx
     name: my-nginx-svc
     namespace: default
   spec:
     ports:
     - port: 80
       protocol: TCP
       targetPort: 80
     selector:
       app: nginx
     type: LoadBalancer

   Field	Description
   kind	Defines the resource object type as Service.
   metadata	Defines basic information about the service, such as its name, labels, and namespace.
   metadata.annotations	ACS provides a rich set of annotations for configuring LoadBalancer services. In this example, the annotation service.beta.kubernetes.io/alibaba-cloud-loadbalancer-address-type specifies intranet (internal access). For more annotations, see Configure a Classic Load Balancer (CLB) by using annotations.
   spec.selector	The label selector for the service. The service matches Pods with these labels and routes traffic to them.
   spec.ports.port	The port exposed on the service's ClusterIP. Clients inside the cluster access the service at clusterIP:port.
   spec.ports.targetPort	The port on the backend Pods. Traffic arriving at the port is forwarded by kube-proxy to the targetPort on the backend Pod.
   spec.type	Specifies how the service is exposed. LoadBalancer: Exposes the service using an Alibaba Cloud CLB instance. If you do not specify an existing CLB instance for the service, a public-facing CLB instance is created by default. To create a service with internal access and a corresponding private CLB, set the service.beta.kubernetes.io/alibaba-cloud-loadbalancer-address-type annotation to intranet. ClusterIP: Exposes the service on a cluster-internal IP address for access from within the cluster. Important Alibaba Cloud Container Compute Service (ACS) does not support services of the NodePort type. Attempts to create a service of this type fail or the service does not take effect.

3. Run the following command to create the service:

   kubectl apply -f my-nginx-svc.yaml

4. Run the following command to verify that the service is created:

   kubectl get svc my-nginx-svc

   Expected output:

   NAME           TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)   AGE
   my-nginx-svc   LoadBalancer   172.16.XX.XX   192.168.XX.XX   80/TCP    13s

Related operations

kubectl get service my-nginx-svc

NAME           TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)   AGE
my-nginx-svc   LoadBalancer   172.16.XX.XX   192.168.XX.XX   80/TCP    13s

kubectl delete service my-nginx-svc