docker - Kubernetes和Docker:如何让两个服务正确通信

Question

我有两个Java微服务( caller.jar ，调用被称为.jar )

我们可以通过 env-var CALLERPORT设置 call 者服务http端口，并通过env-var CALLEDADDRESS设置被叫服务的地址。
因此，调用方使用两个env-var。

我们还必须设置称为 service env-var CALLEDPORT的，以便设置被调用服务正在侦听HTTP请求的特定http端口。

我不知道确切如何从Dockerfile中公开这些变量，以便使用Kubernetes进行设置。

这是我制作两个Dockerfile的方法:

调用方的Dockerfile

FROM openjdk:8-jdk-alpine

# ENV CALLERPORT     (it's own port)
# ENV CALLEDADDRESS  (the other service address)

ADD caller.jar /

CMD ["java", "-jar", "caller.jar"]

名为的Dockerfile

FROM openjdk:8-jdk-alpine

# ENV CALLEDPORT (it's own port)

ADD called.jar /

CMD ["java", "-jar", "called.jar"]

通过这些，我制作了两个 Docker镜像:

我的帐户/ call 者

myaccount /称为

然后，我做了两个Deployments.yaml，以便让K8s使用副本和负载平衡器部署(在minikube上)两个微服务。

Deployment-caller.yaml

apiVersion: v1
kind: Service              
metadata:
  name: caller-loadbalancer
spec:
  type: LoadBalancer       
  ports:
  - port: 8080               
    targetPort: 8080        
  selector:            
    app: caller    
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: caller
  labels:
    app: caller
spec:
  replicas: 2                                             
  minReadySeconds: 15
  strategy:
    type: RollingUpdate                                   
    rollingUpdate: 
      maxUnavailable: 1                                   
      maxSurge: 1                                         
  selector:
    matchLabels:
      app: caller
      tier: caller
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: caller
        tier: caller
    spec:
      containers:
      - image: myaccount/caller
        name: caller
        env:
        - name: CALLERPORT
          value: "8080"
        - name: CALLEDADDRESS
          value: called-loadbalancer  # WHAT TO PUT HERE?!
        ports:
        - containerPort: 8080
          name: caller

而部署称为.yaml

apiVersion: v1
kind: Service              
metadata:
  name: called-loadbalancer
spec:
  type: LoadBalancer       
  ports:
  - port: 8081               
    targetPort: 8081        
  selector:            
    app: called    
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: called
  labels:
    app: called
spec:
  replicas: 2                                             
  minReadySeconds: 15
  strategy:
    type: RollingUpdate                                   
    rollingUpdate: 
      maxUnavailable: 1                                   
      maxSurge: 1                                         
  selector:
    matchLabels:
      app: called
      tier: called
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: called
        tier: called
    spec:
      containers:
      - image: myaccount/called
        name: called
        env:
        - name: CALLEDPORT
          value: "8081"
        ports:
        - containerPort: 8081
          name: called

重要提示:
如果单独调用单个服务(例如调用运行状况检查端点)，则可以很好地工作，但是，当调用涉及两个服务之间的通信的端点时，就会出现此错误:

java.net.UnknownHostException: called

Pod正确运行且处于 Activity 状态，但是我想问题是Deployment.yaml的一部分，在其中必须定义如何查找指向的服务，因此在这里:

spec:
  containers:
    - image: myaccount/caller
      name: caller
      env:
        - name: CALLERPORT
          value: "8080"
        - name: CALLEDADDRESS
          value: called-loadbalancer  # WHAT TO PUT HERE?!
        ports:
        - containerPort: 8080
          name: caller

都没有

called

也不

called-loadbalancer

也不

http://caller 


kubectl get pods,svc -o wide

NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE       NOMINATED NODE   READINESS GATES
pod/called-855cc4d89b-4gf97   1/1       Running   0          3m23s     172.17.0.4   minikube   <none>           <none>
pod/called-855cc4d89b-6268l   1/1       Running   0          3m23s     172.17.0.5   minikube   <none>           <none>
pod/caller-696956867b-9n7zc   1/1       Running   0          106s      172.17.0.6   minikube   <none>           <none>
pod/caller-696956867b-djwsn   1/1       Running   0          106s      172.17.0.7   minikube   <none>           <none>

NAME                          TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE       SELECTOR
service/called-loadbalancer   LoadBalancer   10.99.14.91    <pending>     8081:30161/TCP   171m      app=called
service/caller-loadbalancer   LoadBalancer   10.107.9.108   <pending>     8080:30078/TCP   65m       app=caller
service/kubernetes            ClusterIP      10.96.0.1      <none>        443/TCP          177m      <none>

如果放在deploy.yaml的这一行中，则可以正常工作。
那该放在那一行呢？

Answer 1

要访问Kubernetes内部的服务，您应该使用以下DNS:

http://caller-loadbalancer.default.svc.cluster.local:8080

http://called-loadbalancer.default.svc.cluster.local:8081