Spring Cloud Kubernetes 發現伺服器

Spring Cloud Kubernetes 發現伺服器提供 HTTP 端點，應用程式可以使用這些端點來收集 Kubernetes 叢集中可用服務的資訊。使用 spring-cloud-starter-kubernetes-discoveryclient 的應用程式可以使用 Spring Cloud Kubernetes 發現伺服器來向該啟動器提供的 DiscoveryClient 實現提供資料。

許可權

Spring Cloud 發現伺服器使用 Kubernetes API 伺服器來獲取 Pod、Service 和 Endpoint 資源的資料，因此它需要這些端點的列表、監視和獲取許可權。請參閱下面的 Kubernetes 部署 YAML 示例，瞭解如何在 Kubernetes 上配置服務帳戶。

端點

伺服器暴露了三個端點。

`/apps`

傳送到 /apps 的 GET 請求將返回一個可用服務的 JSON 陣列。每個專案都包含 Kubernetes 服務的名稱和服務例項資訊。以下是一個示例響應。

[
   {
      "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"
         }
      ]
   }
]

`/apps/{name}`

對 /apps/{name} 的 GET 請求可用於獲取給定服務所有例項的例項資料。以下是對 /apps/kubernetes 傳送 GET 請求時的示例響應。

[
     {
        "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"
     }
]

`/app/{name}/{instanceid}`

對 /app/{name}/{instanceid} 傳送的 GET 請求將返回給定服務特定例項的例項資料。以下是對 /app/kubernetes/1234 傳送 GET 請求時的示例響應。

 {
    "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"
 }

部署 YAML

您可以從 GitHub 上的原始碼構建 Docker 映象，並使用它部署到 Kubernetes。

以下是一個示例部署 YAML，您可以用來將 Kubernetes 發現伺服器部署到 Kubernetes。

---
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: ["pods", "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:
          serviceAccountName: spring-cloud-kubernetes-discoveryserver
          containers:
          - name: spring-cloud-kubernetes-discoveryserver
            image: springcloud/spring-cloud-kubernetes-discoveryserver:3.1.0
            imagePullPolicy: IfNotPresent
            readinessProbe:
              httpGet:
                port: 8761
                path: /actuator/health/readiness
            livenessProbe:
              httpGet:
                port: 8761
                path: /actuator/health/liveness
            ports:
            - containerPort: 8761