关于kubernetes:聊聊如何停止某个pod的流量

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本文次要钻研一下如何进行某个 pod 的流量

# Copyright Istio Authors
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##################################################################################################
# Ratings service
##################################################################################################
apiVersion: v1
kind: Service
metadata:
  name: ratings
  labels:
    app: ratings
    service: ratings
spec:
  ports:
  - port: 8080
    name: http
  selector:
    app: ratings
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ratings-v1
  labels:
    app: ratings
    version: v1
spec:
  replicas: 3
  selector:
    matchLabels:
      app: ratings
      version: v1
  template:
    metadata:
      labels:
        app: ratings
        version: v1
    spec:
      containers:
      - name: ratings
        image: jvm-tools-demo:v2
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080
        livenessProbe:
          httpGet:
            path: /actuator/health/liveness
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 10
          periodSeconds: 10
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /actuator/health/readiness
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 10
          periodSeconds: 10
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        securityContext:
          runAsUser: 1000
        resources:
          # keep request = limit to keep this container in guaranteed class
          requests:
            cpu: 50m
            memory: 128Mi          
---

这里咱们配置了 livenessProbe 及 readinessProbe

org/springframework/boot/actuate/availability/ReadinessStateHealthIndicator.java

public class ReadinessStateHealthIndicator extends AvailabilityStateHealthIndicator {public ReadinessStateHealthIndicator(ApplicationAvailability availability) {super(availability, ReadinessState.class, (statusMappings) -> {statusMappings.add(ReadinessState.ACCEPTING_TRAFFIC, Status.UP);
            statusMappings.add(ReadinessState.REFUSING_TRAFFIC, Status.OUT_OF_SERVICE);
        });
    }

    @Override
    protected AvailabilityState getState(ApplicationAvailability applicationAvailability) {return applicationAvailability.getReadinessState();
    }

}

springboot 的 ReadinessStateHealthIndicator 提供了 /actuator/health/readiness 用于检测是否能够接管流量

AvailabilityChangeEvent.publish(applicationContext, ReadinessState.REFUSING_TRAFFIC);
        return ReadinessState.REFUSING_TRAFFIC;

AvailabilityChangeEvent 提供了 publish 办法，能够将 ReadinessState 变更为 REFUSING_TRAFFIC

kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
ratings-v1-54bf49c9bc-d88jb   1/1     Running   0          4m34s
ratings-v1-54bf49c9bc-dfjhh   1/1     Running   0          4m34s
ratings-v1-54bf49c9bc-flvcq   0/1     Running   0          4m34s