ClusterIP
ClusterIP
我们将使用以下命令从一个 Pod 模板创建一个 Pod。
$ kubectl run nginx --image nginx --dry-run=client -o yaml > pod-template.yaml
$ kubectl create -f pod-template.yaml
pod/nginx created
$ kubectl expose pod nginx --port=80
service/nginx exposed
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 25m
nginx ClusterIP 10.104.209.243 <none> 80/TCP 7m15s
运行以下命令查看 Nginx 服务的详细信息。
$ kubectl describe service nginx
Name: nginx
Namespace: default
Labels: run=nginx
Annotations: <none>
Selector: run=nginx
Type: ClusterIP
IP: 10.104.209.243
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.46.0.0:80
Session Affinity: None
Events: <none>
访问 Ningx。根据自己的环境，用下面的命令更改集群 IP。
$ curl 10.104.209.243
...
<title>Welcome to nginx!</title>
...
$ kubectl logs -f nginx
10.40.0.0 - - [10/May/2020:17:31:56 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.58.0" "-"
$ kubectl delete svc nginx
service "nginx" deleted
然后使用 vim primeiro-service-clusterip.yaml：
apiVersion : v1
kind : Service
metadata :
labels :
run : nginx
name : nginx-clusterip
namespace : default
spec :
ports :
- port : 80
protocol : TCP
targetPort : 80
selector :
run : nginx
type : ClusterIP
创建服务：
$ kubectl create -f primeiro-service-clusterip.yaml
service/nginx-clusterip created
$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 28m
nginx-clusterip ClusterIP 10.109.70.243 <none> 80/TCP 71s
$ kubectl describe service nginx-clusterip
Name: nginx-clusterip
Namespace: default
Labels: run=nginx
Annotations: <none>
Selector: run=nginx
Type: ClusterIP
IP: 10.109.70.243
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.46.0.1:80
Session Affinity: None
Events: <none>
$ kubectl delete -f primeiro-service-clusterip.yaml
service "nginx-clusterip" deleted
然后我们修改下 sessionAffinity 属性：
apiVersion : v1
kind : Service
metadata :
labels :
run : nginx
name : nginx-clusterip
namespace : default
spec :
ports :
- port : 80
protocol : TCP
targetPort : 80
selector :
run : nginx
sessionAffinity : ClientIP
type : ClusterIP
再次创建服务：
$ kubectl create -f primeiro-service-clusterip.yaml
service/nginx-clusterip created
$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 29m
nginx-clusterip ClusterIP 10.96.44.114 <none> 80/TCP 7s
$ kubectl describe service nginx
Name: nginx-clusterip
Namespace: default
Labels: run=nginx
Annotations: <none>
Selector: run=nginx
Type: ClusterIP
IP: 10.96.44.114
Port: <unset> 80/TCP
TargetPort: 80/TCP
Endpoints: 10.46.0.1:80
Session Affinity: ClientIP
Events: <none>
有了这些，现在我们就可以维护会话了，也就是说，它将与同一个 pod 保持连接，尊重客户端的原 IP。如果有必要，可以将超时值改为 sessionAffinity(默认值为 10800 秒，即 3 小时)，只需添加以下配置即可。
sessionAffinityConfig:
clientIP:
timeoutSeconds: 10
现在我们可以删除服务。
$ kubectl delete -f primeiro-service-clusterip.yaml
service "nginx-clusterip" deleted
EndPoint
每当我们创建一个服务，就会自动创建一个端点。端点无非就是服务要使用的 IP pod，比如我们创建服务类型 ClusterIP 的时候就有你的 IP，对吧？现在，当我们打到这个 IP 的时候，它就会通过这个 IP，即 EndPoint 重定向连接到 Pod。要列出已创建的 EndPoints，请运行命令。
$ kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 10.142.0.5:6443 4d
$ kubectl describe endpoints kubernetes
Name: kubernetes
Namespace: default
Labels: <none>
Annotations: <none>
Subsets:
Addresses: 172.31.17.67
NotReadyAddresses: <none>
Ports:
Name Port Protocol
---- ---- --------
https 6443 TCP
Events: <none>
让我们做一个例子，对于这个，我们将执行一个部署的创建，将副本的数量增加到 3 个，然后是一个服务，这样我们就可以更详细地看到将创建的端点。
$ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
$ kubectl get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 1/1 1 1 5s
将 nginx 部署扩展到 3 个副本。
$ kubectl scale deployment nginx --replicas=3
deployment.apps/nginx scaled
$ kubectl get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
nginx 3/3 3 3 1m5s
$ kubectl expose deployment nginx --port=80
service/nginx exposed
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 40m
nginx ClusterIP 10.98.153.22 <none> 80/TCP 6s
访问 nginx：
curl 10.98.153.22
...
<h1>Welcome to nginx!</h1>
...
查看端点：
kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 172.31.17.67:6443 44m
nginx 10.32.0.2:80,10.32.0.3:80,10.46.0.2:80 3m31s
查看 nginx 端点的详细信息：
$ kubectl describe endpoints nginx
Name: nginx
Namespace: default
Labels: app=nginx
Annotations: endpoints.kubernetes.io/last-change-trigger-time: 2020-05-10T17:47:05Z
Subsets:
Addresses: 10.32.0.2,10.32.0.3,10.46.0.2
NotReadyAddresses: <none>
Ports:
Name Port Protocol
---- ---- --------
<unset> 80 TCP
Events: <none>
以 YAML 格式查看端点。
$ kubectl get endpoints -o yaml
apiVersion: v1
items:
- apiVersion: v1
kind: Endpoints
metadata:
creationTimestamp: "2020-05-10T17:06:12Z"
managedFields:
- apiVersion: v1
fieldsType: FieldsV1
fieldsV1:
f:subsets: {}
manager: kube-apiserver
operation: Update
time: "2020-05-10T17:06:12Z"
name: kubernetes
namespace: default
resourceVersion: "163"
selfLink: /api/v1/namespaces/default/endpoints/kubernetes
uid: 39f1e237-f9cc-4553-a32d-95402ff52f6c
...
- ip: 10.46.0.2
nodeName: elliot-03
targetRef:
kind: Pod
name: nginx-f89759699-dmt4t
namespace: default
resourceVersion: "6805"
uid: 6a9c4639-78ee-44c6-8eb1-4fd90d308189
ports:
- port: 80
protocol: TCP
kind: List
metadata:
resourceVersion: ""
selfLink: ""
移除相关的资源：
$ kubectl delete deployment nginx
deployment.apps "nginx" deleted
$ kubectl delete service nginx
service "nginx" deleted