ClusterIP
Scenario
ClusterIP Services allow workloads in the same cluster to use their cluster-internal domain names to access each other.
The cluster-internal domain name format is <Service name>.<Namespace of the workload>.svc.cluster.local:<Port>, for example, nginx.default.svc.cluster.local:80.
Figure 1 shows the mapping relationships between access channels, container ports, and access ports.
Creating a ClusterIP Service
- Log in to the CCE console and click the cluster name to access the cluster console.
- In the navigation pane, choose Services & Ingresses. In the upper right corner, click Create Service.
- Configure intra-cluster access parameters.
- Service Name: Specify a Service name, which can be the same as the workload name.
- Service Type: Select ClusterIP.
- Namespace: namespace that the workload belongs to.
- Selector: Add a label and click Confirm. The Service will use this label to select pods. You can also click Reference Workload Label to use the label of an existing workload. In the dialog box that is displayed, select a workload and click OK.
- Protocol Version: Select the IP address of different versions based on service requirements. For details, see Creating an IPv4/IPv6 Dual-Stack Cluster in CCE. This parameter is available only in clusters of v1.15 or later with IPv6 enabled (set during cluster creation).
- Ports
- Protocol: protocol used by the Service.
- Service Port: port used by the Service. The port number ranges from 1 to 65535.
- Container Port: listener port of the workload. For example, Nginx uses port 80 by default.
- Click OK.
Setting the Access Type Using kubectl
You can configure Service access using kubectl. This section uses an Nginx workload as an example to describe how to implement intra-cluster access using kubectl.
- Use kubectl to access the cluster. For details, see Connecting to a Cluster Using kubectl.
- Create and edit the nginx-deployment.yaml and nginx-clusterip-svc.yaml files.
The file names are user-defined. nginx-deployment.yaml and nginx-clusterip-svc.yaml are merely example file names.
vi nginx-deployment.yamlapiVersion: apps/v1 kind: Deployment metadata: name: nginx spec: replicas: 1 selector: matchLabels: app: nginx template: metadata: labels: app: nginx spec: containers: - image: nginx:latest name: nginx imagePullSecrets: - name: default-secret
vi nginx-clusterip-svc.yamlapiVersion: v1 kind: Service metadata: labels: app: nginx name: nginx-clusterip spec: ports: - name: service0 port: 8080 # Port for accessing a Service. protocol: TCP # Protocol used for accessing a Service. The value can be TCP or UDP. targetPort: 80 # Port used by a Service to access the target container. This port is closely related to the applications running in a container. In this example, the Nginx image uses port 80 by default. selector: # Label selector. A Service selects a pod based on the label and forwards the requests for accessing the Service to the pod. In this example, select the pod with the app:nginx label. app: nginx type: ClusterIP # Type of a Service. ClusterIP indicates that a Service is only reachable from within the cluster.
- Create a workload.
kubectl create -f nginx-deployment.yaml
If information similar to the following is displayed, the workload has been created.
deployment "nginx" created
kubectl get po
If information similar to the following is displayed, the workload is running.
NAME READY STATUS RESTARTS AGE nginx-2601814895-znhbr 1/1 Running 0 15s
- Create a Service.
kubectl create -f nginx-clusterip-svc.yaml
If information similar to the following is displayed, the Service is being created.
service "nginx-clusterip" created
kubectl get svc
If information similar to the following is displayed, the Service has been created, and a cluster-internal IP address has been assigned to the Service.
# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.247.0.1 <none> 443/TCP 4d6h nginx-clusterip ClusterIP 10.247.74.52 <none> 8080/TCP 14m
- Access the Service.
A Service can be accessed from containers or nodes in a cluster.
Create a pod, access the pod, and run the curl command to access IP address:Port or the domain name of the Service, as shown in the following figure.
The domain name suffix can be omitted. In the same namespace, you can directly use nginx-clusterip:8080 for access. In other namespaces, you can use nginx-clusterip.default:8080 for access.
# kubectl run -i --tty --image nginx:alpine test --rm /bin/sh If you do not see a command prompt, try pressing Enter. / # curl 10.247.74.52:8080 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html> / # curl nginx-clusterip.default.svc.cluster.local:8080 ... <h1>Welcome to nginx!</h1> ... / # curl nginx-clusterip.default:8080 ... <h1>Welcome to nginx!</h1> ... / # curl nginx-clusterip:8080 ... <h1>Welcome to nginx!</h1> ...
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.See the reply and handling status in My Cloud VOC.
For any further questions, feel free to contact us through the chatbot.
Chatbot