Spring Cloud Kubernetes Discovery Server
Spring Cloud Kubernetes Discovery Server 提供了 HTTP 端点,应用程序可以使用这些端点来收集有关 Kubernetes 集群中可用服务的详细信息。使用 spring-cloud-starter-kubernetes-discoveryclient
的应用程序可以使用 Spring Cloud Kubernetes Discovery Server 向该 starter 提供的 DiscoveryClient
实现提供数据。
Permissions
Spring Cloud Discovery 服务器使用 Kubernetes API 服务器获取有关 Pod、服务和端点资源的数据,因此它需要列示、监视和获取权限才能使用这些端点。有关如何配置 Kubernetes 上的服务帐户的示例,请参见以下示例 Kubernetes 部署 YAML。
Endpoints
服务器公开了三个端点。
/apps
发送到 /apps
的 GET
请求将返回一个 JSON 数组,其中包含可用服务。每项都包含 Kubernetes 服务名称和服务实例信息。以下是示例响应。
[
{
"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}
通过向 /apps/{name}
发出 GET
请求,可以获取给定服务的所有实例的实例数据。下面展示了向 /apps/kubernetes
发出 GET
请求时的示例响应。
[
{
"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}
通过向 /app/{name}/{instanceid}
发出 GET
请求,将会返回给定服务的特定实例的实例数据。下面展示了向 /app/kubernetes/1234
发出 GET
请求时的示例响应。
{
"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"
}
Deployment YAML
Spring Cloud Discovery Server 的镜像托管在 Docker Hub 上。但是,如果您需要自定义发现服务器行为或希望自己构建该映像,那么您可以轻松地从 source code on GitHub 构建自己的映像并使用该映像。
下面是一个示例部署 YAML,您可以使用它将 Kubernetes Discovery Server 部署到 Kubernetes 中。
---
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