Kubernetes-没有选择器的服务

微生嘉祥

2023-03-14

问题内容：

我在没有选择器的情况下在Kubernetes的服务中苦苦挣扎。群集通过kops安装在AWS上。我有一个带有3个Nginx Pod的部署，暴露了端口80：

apiVersion: apps/v1
kind: Deployment
metadata:
 name: ngix-dpl                 # Name of the deployment object
 labels:
   app: nginx                     
spec:
 replicas: 3                    # Number of instances in the deployment
 selector:                      # Selector identifies pods to be
     matchLabels:               #     part of the deployment 
        app: nginx              #     by matching of the label "app" 
 template:                      # Templates describes pods of the deployment
   metadata:
     labels:                    # Defines key-value map
       app: nginx               # Label to be recognized by other objects
   spec:                        #     as deployment or service
     containers:                # Lists all containers in the pod
     - name: nginx-pod          # container name
       image: nginx:1.17.4      # container docker image
       ports:
       - containerPort: 80      # port exposed by container

创建部署后，我记下了IP地址：

$ kubectl get pods -o wide | awk {'print $1" " $3" " $6'} | column -t
                                                                           NAME                       STATUS   IP
curl                       Running  100.96.6.40
ngix-dpl-7d6b8c8944-8zsgk  Running  100.96.8.53
ngix-dpl-7d6b8c8944-l4gwk  Running  100.96.6.43
ngix-dpl-7d6b8c8944-pffsg  Running  100.96.8.54

并创建了一个服务于IP地址的服务：

apiVersion: v1
kind: Service
metadata:
  name: dummy-svc
  labels:
    app: nginx
spec:
 ports:
    - protocol: TCP
      port: 80
      targetPort: 80
---
apiVersion: v1
kind: Endpoints
metadata:
  name: dummy-svc 
subsets: 
  - addresses:
    - ip: 100.96.8.53
    - ip: 100.96.6.43
    - ip: 100.96.8.54
    ports:
    - port: 80
      name: http

服务已成功创建：

$ kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
dummy-svc    ClusterIP   100.64.222.220   <none>        80/TCP    32m
kubernetes   ClusterIP   100.64.0.1       <none>        443/TCP   5d14h

不幸的是，我尝试通过服务从相同名称空间的另一个Pod连接到Nginx失败：

$ curl 100.64.222.220
curl: (7) Failed to connect to 100.64.222.220 port 80: Connection refused

我可以直接成功地连接到Nginx Pod：

$ curl 100.96.8.53
<!DOCTYPE html>
<html>
<head>
....

我注意到我的服务没有任何端点。但是我不确定应该在此处显示手动端点：

$ kubectl get svc/dummy-svc -o yaml
apiVersion: v1
kind: Service
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |      
       {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app":"nginx"},"name":"dummy-svc","namespace":"default"},"spec":{"ports":[{"port":80,"protocol":"TCP","targetPort":80}]}}
  creationTimestamp: "2019-11-22T08:41:29Z"
  labels:
    app: nginx
  name: dummy-svc
  namespace: default
  resourceVersion: "4406151"
  selfLink: /api/v1/namespaces/default/services/dummy-svc
  uid: e0aa9d01-0d03-11ea-a19c-0a7942f17bf8
spec:
  clusterIP: 100.64.222.220
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

我知道这不是服务的正确用例，使用pod选择器会使它工作。但我想强调一下为什么此配置不起作用。我不知道在哪里寻找解决方案。任何提示将不胜感激。

问题答案：

如果您从端点配置中删除“名称”字段，则它起作用。它应该看起来像这样：

apiVersion: v1
kind: Endpoints
metadata:
  name: dummy-svc 
subsets: 
  - addresses:
    - ip: 172.17.0.4
    - ip: 172.17.0.5
    - ip: 172.17.0.6
    ports:
    - port: 80

Kubernetes-没有选择器的服务

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