🌵Endpoints
默认 Endpoints
通常情况下，在创建 Service 的时候，会默认创建 Endpoints，例如：
yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.17.2
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx
spec:
type: ClusterIP
selector:
app: nginx
ports:
- port: 80
protocol: TCP
targetPort: 80查看 Service：
bash
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
nginx ClusterIP 10.107.227.24 <none> 80/TCP 2m查看 Pod：
bash
$ kubectl get po -owide
NAME READY STATUS RESTARTS AGE IP NODE
nginx-56b7d6bcf7-8pf6f 1/1 Running 0 1m 10.1.0.43 docker-for-desktop
nginx-56b7d6bcf7-bl9vh 1/1 Running 0 1m 10.1.0.45 docker-for-desktop
nginx-56b7d6bcf7-wl4qb 1/1 Running 0 1m 10.1.0.44 docker-for-desktop查看 Service：
bash
$ kubectl get endpoints
NAME ENDPOINTS AGE
nginx 10.1.0.43:80,10.1.0.44:80,10.1.0.45:80 3m
$ kubectl get endpoints nginx -oyaml
apiVersion: v1
kind: Endpoints
metadata:
creationTimestamp: 2019-08-14T15:09:13Z
name: nginx
namespace: default
resourceVersion: "670768"
selfLink: /api/v1/namespaces/default/endpoints/nginx
uid: 7a0d276e-bea5-11e9-98fc-025000000001
subsets:
- addresses:
- ip: 10.1.0.43
nodeName: docker-for-desktop
targetRef:
kind: Pod
name: nginx-56b7d6bcf7-8pf6f
namespace: default
resourceVersion: "670758"
uid: 7a11eab2-bea5-11e9-98fc-025000000001
- ip: 10.1.0.44
nodeName: docker-for-desktop
targetRef:
kind: Pod
name: nginx-56b7d6bcf7-wl4qb
namespace: default
resourceVersion: "670761"
uid: 7a10580e-bea5-11e9-98fc-025000000001
- ip: 10.1.0.45
nodeName: docker-for-desktop
targetRef:
kind: Pod
name: nginx-56b7d6bcf7-bl9vh
namespace: default
resourceVersion: "670766"
uid: 7a124e66-bea5-11e9-98fc-025000000001
ports:
- port: 80
protocol: TCP可以看到，默认的 Endpoints 即为所选中的 Pod 的集合。
自定义 Endpoints
如果 Service 没有定义 Selector，那么它默认不会选中任何 Pod，也就不会自动创建 Endpoints。可以自定义 Endpoints 来使得 Service 使用集群外部的服务。例如：
yaml
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
ports:
- protocol: TCP
port: 80
---
apiVersion: v1
kind: Endpoints
metadata:
name: my-service
subsets:
- addresses:
- ip: 192.168.1.3
ports:
- port: 9000
protocol: TCP甚至可以指定多组 subsets：
yaml
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
ports:
- protocol: TCP
port: 80
---
apiVersion: v1
kind: Endpoints
metadata:
name: my-service
subsets:
- addresses:
- ip: 192.168.1.3
ports:
- port: 9000
protocol: TCP
- addresses:
- ip: 192.168.1.3
ports:
- port: 9001
protocol: TCP需要特别注意的是，Endpoints 的 name 和 Service 的 name 必须保持一致。