The WebSocket protocol enables continuous two-way communications between a client and a server. This ensures persistent connections and low latency. When a Container Service for Kubernetes (ACK) cluster accesses the external WebSocket service, a cloud-native gateway receives and forwards requests and distributes the requests to specific backend services based on the predefined routing rules. This topic describes how to deploy a WebSocket application in a Container Service for Kubernetes cluster and forward requests by using a cloud-native gateway.
Prerequisites
An ACK cluster is created. For more information, see Create an ACK managed cluster.
An MSE cloud-native gateway is created. For more information, see Create a cloud-native gateway.
Step 1: Deploy a WebSocket application in the ACK cluster
For more information about how to deploy an application, see Create a stateless application by using a Deployment.
In this example, the ACK cluster is used for service discovery. The backend service is registered with CoreDNS by using annotation-based service APIs. The backend service in this example provides multiple WebSocket APIs. The WebSocket application that is deployed in the ACK cluster uses the following resource configuration:
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: sockbin
name: sockbin-app
namespace: default
spec:
progressDeadlineSeconds: 600
replicas: 2
revisionHistoryLimit: 10
selector:
matchLabels:
app: sockbin
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate
template:
metadata:
labels:
app: sockbin
spec:
containers:
- image: therebelrobot/sockbin
imagePullPolicy: Always
name: sockbin
ports:
- containerPort: 4080
protocol: TCP
resources:
limits:
cpu: 500m
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
---
apiVersion: v1
kind: Service
metadata:
labels:
app: sockbin
name: sockbin-service
namespace: default
spec:
ports:
- name: http
port: 4080
protocol: TCP
targetPort: 4080
selector:
app: sockbin
sessionAffinity: None
type: NodePortStep 2: Use the cloud-native gateway to route requests of the WebSocket application
Add the ACK cluster as a service source of the cloud-native gateway and add the Sockbin service.
Add a service source
Log on to the MSE console, and select a region in the top navigation bar.
In the left-side navigation pane, choose Cloud-native Gateway > Gateways. On the Gateways page, click the name of the gateway.
In the left-side navigation pane, click Routes. On the page that appears, click the Sources tab.
On the Source tab, click Add Source. In the Add Source panel, configure the parameters, and click OK.
Parameter
Description
Source Type
Select Container Service.
ACK/ACK Serverless Cluster
Select the cluster in which your backend service is deployed.
Listen to Kubernetes Ingress
If you turn on the switch, the cloud-native gateway automatically listens to the changes of Ingress resources and makes the listened configurations of domain names and routes of the Ingress resources take effect.
If you turn off the switch, the cloud-native gateway no longer listens to the changes of Ingress resources and makes the listened configurations of domain names and routes of the Ingress resources become ineffective.
NoteThe priorities of the domain names and routes that are manually configured in the MSE console are higher than the priorities of the listened domain names and routes of the Ingress resources.
Add a service
Log on to the MSE console, and select a region in the top navigation bar.
In the left-side navigation pane, choose Cloud-native Gateway > Gateways. On the Gateways page, click the name of the gateway.
In the left-side navigation pane, click Routes. On the page that appears, click the Services tab.
On the Services tab, click Add Service. In the Add Service panel, configure the parameters, and click OK.
Parameter
Description
Service Source
Select Container Service.
Namespace
Select the namespace of the destination cluster.
Services
Select one or more services.
Add a route from the gateway to the Sockbin service
Log on to the MSE console, and select a region in the top navigation bar.
In the left-side navigation pane, choose Cloud-native Gateway > Gateways. On the Gateways page, click the name of the gateway.
In the left-side navigation pane, click Routes, and click the Routes tab.
On the Routes tab, click Add Route. On the page that appears, configure the parameters, and click Save and Advertise.
Parameter
Description
Routing Rule Name
Enter
sockbin-route.Domain name
Select the default associated domain name * from the drop-down list.
Path
Select Prefix from the matching condition drop-down list and enter
/in the field.Scenario
Select Single Service.
Backend Service
Select the destination service and service port.
Verify the result
You can use one of the following methods to verify the availability of the WebSocket service.
Method 1: Conduct testing on the Sockbin service page
Log on to the MSE console, and select a region in the top navigation bar.
In the left-side navigation pane, choose Cloud-native Gateway > Gateways. On the Gateways page, click the name of the gateway.
On the Gateway Ingress tab of the Overview page of the gateway, find the public endpoint of the Server Load Balancer (SLB) instance that is associated with the gateway. Then, enter the endpoint in the address bar of your browser and press Enter.
The gateway performs routing based on the domain name and path that are included in the WebSocket handshake request to open the Sockbin service page.
Method 2: Conduct testing on the WebSocket client in a specific programming language
For example, you can use the WebSocket client in Python to receive a server response with a latency of 1 second.
#!/usr/bin/env python
import asyncio
import websockets
async def hello():
async with websockets.connect("ws://ip_addr/delay/1000") as websocket:
await websocket.send("Hello Test")
text = await websocket.recv()
print(text)
asyncio.run(hello())