Container Compute Service:Expose an application using a Service

Method 1: Create a Service by 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 method used to access the Service. The following types are available: Cluster IP: Exposes the Service on a cluster-internal IP address. This type of service is reachable only from within the cluster. Note A Headless Service can be configured to interface with other service discovery mechanisms, independent of the Kubernetes native implementation. SLB: Corresponds to the LoadBalancer type. It uses an Alibaba Cloud Server Load Balancer (SLB) instance to expose the service. Select Public Access or Internal Access. It routes external traffic to the internal ClusterIP service. Create Resource: For Pay-by-specification, click Change Specification to modify the SLB specification. Use Existing Resource: Select an existing SLB specification from the list. Note Using an existing SLB instance overwrites its existing listeners. To prevent accidental deletion, you cannot reuse SLB instances that are automatically provisioned by a service. You can only reuse SLB instances that you create manually. If multiple Services reuse the same SLB instance, ensure their frontend listener ports are unique to avoid conflicts. When you reuse an SLB instance, Kubernetes uses the listener name and virtual server group name as unique identifiers. Do not modify these names. Reusing an SLB instance across different clusters is not supported.	Create Service: Service Type: SLB SLB Type: CLB Select Resource: Create Resource Create CLB Instance: Access Method: Internal Access Use the default values for other configurations.
   Backend	Select the backend application to which the Service will be bound. If no backend is selected, Kubernetes does not create the 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 file) and a container port (the targetPort field in the Service YAML file). 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 Service. Note Alibaba Cloud-specific annotations take effect only when Service Type is set to SLB. For example, setting service.beta.kubernetes.io/alicloud-loadbalancer-bandwidth: 2 sets the peak bandwidth of the service to 2 Mbit/s to control traffic. For more annotations, see Configure a Classic Load Balancer (CLB) instance using annotations.	None
   Label	Add a label to identify the Service.	None

   After you configure the parameters, click OK.

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

Method 2: Create a service by using kubectl

1. Connect to a Kubernetes cluster using kubectl.

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

   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	Specifies that the resource type is Service.
   metadata	Defines basic information for the Service, such as its name, label, and namespace.
   metadata.annotations	ACK provides many annotations for configuring SLB instances. For example, in the YAML file, service.beta.kubernetes.io/alibaba-cloud-loadbalancer-address-type: "intranet" specifies that the access method of the service is internal. For more annotations, see Configure a Classic Load Balancer (CLB) instance using annotations.
   spec.selector	Defines the selector for the service. The Service uses the selector to find Pods with matching labels and routes traffic to them.
   spec.ports.port	Defines the port exposed by the service's ClusterIP. This is the entry point for clients inside the cluster to access the service (clusterIP:port).
   spec.ports.targetPort	Specifies the port on the backend Pods. Traffic entering through the port is forwarded by kube-proxy to the targetPort of the Pod, and finally to the container.
   spec.type	Defines the access method of the service. LoadBalancer: Exposes the Service using an Alibaba Cloud SLB instance. If you do not specify an existing SLB instance, a public-facing SLB instance is created by default. To create an internal-facing service and a corresponding internal SLB instance, set the service.beta.kubernetes.io/alibaba-cloud-loadbalancer-address-type annotation to intranet. ClusterIP: Exposes the service on an internal IP address within the cluster. This type is used for internal access only. Important Alibaba Cloud Container Compute Service (ACS) does not support the NodePort Service type. Creating a Service of this type will fail or the Service will 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 was 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