15. Spring Cloud Kubernetes 发现服务器

Spring Cloud Kubernetes Discovery Server 提供了应用程序可用于收集信息的 HTTP 端点 关于 Kubernetes 集群中可用的服务。Spring Cloud Kubernetes 发现服务器 可由使用spring-cloud-starter-kubernetes-discoveryclient向 这DiscoveryClient该Starters提供的实现。spring-doc.cadn.net.cn

15.1. 权限

Spring Cloud Discovery 服务器使用 Kubernetes API 服务器来获取有关服务和端点资源的数据，因此它需要列出、监视和 获取使用这些终结点的权限。请参阅下面的示例 Kubernetes 部署 YAML，了解 如何在 Kubernetes 上配置服务帐户。spring-doc.cadn.net.cn

15.2. 端点

服务器公开了三个端点。spring-doc.cadn.net.cn

15.2.1./apps

一个GET请求发送至/apps将返回可用服务的 JSON 数组。每项包含 Kubernetes 服务的名称和服务实例信息。下面是一个示例响应。spring-doc.cadn.net.cn

[
   {
      "name":"spring-cloud-kubernetes-discoveryserver",
      "serviceInstances":[
         {
            "instanceId":"836a2f25-daee-4af2-a1be-aab9ce2b938f",
            "serviceId":"spring-cloud-kubernetes-discoveryserver",
            "host":"10.244.1.6",
            "port":8761,
            "uri":"http://10.244.1.6:8761",
            "secure":false,
            "metadata":{
               "app":"spring-cloud-kubernetes-discoveryserver",
               "kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Service\",\"metadata\":{\"annotations\":{},\"labels\":{\"app\":\"spring-cloud-kubernetes-discoveryserver\"},\"name\":\"spring-cloud-kubernetes-discoveryserver\",\"namespace\":\"default\"},\"spec\":{\"ports\":[{\"name\":\"http\",\"port\":80,\"targetPort\":8761}],\"selector\":{\"app\":\"spring-cloud-kubernetes-discoveryserver\"},\"type\":\"ClusterIP\"}}\n",
               "http":"8761"
            },
            "namespace":"default",
            "scheme":"http"
         }
      ]
   },
   {
      "name":"kubernetes",
      "serviceInstances":[
         {
            "instanceId":"1234",
            "serviceId":"kubernetes",
            "host":"172.18.0.3",
            "port":6443,
            "uri":"http://172.18.0.3:6443",
            "secure":false,
            "metadata":{
               "provider":"kubernetes",
               "component":"apiserver",
               "https":"6443"
            },
            "namespace":"default",
            "scheme":"http"
         }
      ]
   }
]

15.2.2./app/{name}

一个GET请求/app/{name}可用于获取给定实例的所有实例的实例数据 服务。下面是当GET请求向/app/kubernetes.spring-doc.cadn.net.cn

[
     {
        "instanceId":"1234",
        "serviceId":"kubernetes",
        "host":"172.18.0.3",
        "port":6443,
        "uri":"http://172.18.0.3:6443",
        "secure":false,
        "metadata":{
           "provider":"kubernetes",
           "component":"apiserver",
           "https":"6443"
        },
        "namespace":"default",
        "scheme":"http"
     }
]

15.2.3./app/{name}/{instanceid}

一个GET向/app/{name}/{instanceid}将返回特定 给定服务的实例。下面是当GET请求向/app/kubernetes/1234.spring-doc.cadn.net.cn

 {
    "instanceId":"1234",
    "serviceId":"kubernetes",
    "host":"172.18.0.3",
    "port":6443,
    "uri":"http://172.18.0.3:6443",
    "secure":false,
    "metadata":{
       "provider":"kubernetes",
       "component":"apiserver",
       "https":"6443"
    },
    "namespace":"default",
    "scheme":"http"
 }

15.3. 部署 YAML

Spring Cloud Discovery Server 的映像托管在 Docker Hub 上。 但是，如果您需要自定义发现服务器行为或更喜欢自己构建映像，您可以轻松构建自己的映像 图像来自 GitHub 上的源代码并使用它。spring-doc.cadn.net.cn

下面是一个示例部署 YAML，可用于将 Kubernetes 配置观察程序部署到 Kubernetes。spring-doc.cadn.net.cn

---
apiVersion: v1
kind: List
items:
  - apiVersion: v1
    kind: Service
    metadata:
      labels:
        app: spring-cloud-kubernetes-discoveryserver
      name: spring-cloud-kubernetes-discoveryserver
    spec:
      ports:
        - name: http
          port: 80
          targetPort: 8761
      selector:
        app: spring-cloud-kubernetes-discoveryserver
      type: ClusterIP
  - apiVersion: v1
    kind: ServiceAccount
    metadata:
      labels:
        app: spring-cloud-kubernetes-discoveryserver
      name: spring-cloud-kubernetes-discoveryserver
  - apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      labels:
        app: spring-cloud-kubernetes-discoveryserver
      name: spring-cloud-kubernetes-discoveryserver:view
    roleRef:
      kind: Role
      apiGroup: rbac.authorization.k8s.io
      name: namespace-reader
    subjects:
      - kind: ServiceAccount
        name: spring-cloud-kubernetes-discoveryserver
  - apiVersion: rbac.authorization.k8s.io/v1
    kind: Role
    metadata:
      namespace: default
      name: namespace-reader
    rules:
      - apiGroups: ["", "extensions", "apps"]
        resources: ["services", "endpoints"]
        verbs: ["get", "list", "watch"]
  - apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: spring-cloud-kubernetes-discoveryserver-deployment
    spec:
      selector:
        matchLabels:
          app: spring-cloud-kubernetes-discoveryserver
      template:
        metadata:
          labels:
            app: spring-cloud-kubernetes-discoveryserver
        spec:
          serviceAccount: spring-cloud-kubernetes-discoveryserver
          containers:
          - name: spring-cloud-kubernetes-discoveryserver
            image: springcloud/spring-cloud-kubernetes-discoveryserver:2.1.0-SNAPSHOT
            imagePullPolicy: IfNotPresent
            readinessProbe:
              httpGet:
                port: 8761
                path: /actuator/health/readiness
            livenessProbe:
              httpGet:
                port: 8761
                path: /actuator/health/liveness
            ports:
            - containerPort: 8761