从零开始：使用 Kubernetes 部署 Nginx 应用
[root@icv-k8s-node-1 ~]# kubectl create deployment javaedge-nginx --image=nginx:1.24.0
deployment.apps/javaedge-nginx created
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/javaedge-nginx-6996b98cc4-f28r2 1/1 Running 0 29s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 17h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/javaedge-nginx 1/1 1 1 29s
NAME DESIRED CURRENT READY AGE
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 29s
[root@icv-k8s-node-1 ~]# kubectl get all -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/javaedge-nginx-6996b98cc4-f28r2 1/1 Running 0 15m 10.244.26.65 icv-k8s-node-2 <none> <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 17h <none>
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/javaedge-nginx 1/1 1 1 15m nginx nginx:1.24.0 app=javaedge-nginx
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 15m nginx nginx:1.24.0 app=javaedge-nginx,pod-template-hash=6996b98cc4
[root@icv-k8s-node-1 ~]#
可见，这个 nginx 并没有创建在 master 节点， 而是 slave 节点去了。
1 端口暴露
pod的8088端口作为容器的8080端口进行映射，pod要对外提供访问，需要实现service服务，有了 service才能被访问。可以认为service是管理一组pod的。 NodePort：把服务对外暴露公开
[root@icv-k8s-node-1 ~]# kubectl expose deployment javaedge-nginx --port=90 --target-port=80 --type=NodePort
service/javaedge-nginx exposed
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/javaedge-nginx-6996b98cc4-f28r2 1/1 Running 0 29m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/javaedge-nginx NodePort 10.99.205.238 <none> 90:32708/TCP 3m48s
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 18h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/javaedge-nginx 1/1 1 1 29m
NAME DESIRED CURRENT READY AGE
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 29m
[root@icv-k8s-node-1 ~]#
90:32708/TCP中的90是 Service 的端口32708是 NodePort 的端口，表示该 Service 被映射到了 Node 上的32708端口
因此，对外暴露的端口是 32708，而不是 90。在 k8s 集群中，可通过 <NodeIP>:<NodePort> 访问该 Service。
添加了一个新的 Node 组件，表示 Kubernetes 集群中的一个 Node。该 Node 上运行着 Service 的 NodePort 端口（即 NodePort: 32708）。Service 的 NodePort 端口将被映射到 Node 上的该端口。因此，外部客户端可以通过 <NodeIP>:<NodePort> 的方式访问该 Service，并且 <NodeIP> 是该 Node 的 IP 地址，<NodePort> 是 NodePort: 32708。
浏览器访问：
把其中一个node关机。 查看node状态，刚才关机的node已经是 not ready 了。但再次查看pod还有 nginx pod，这就实现中间件的容灾问题，一旦出现宕机，则可以恢复重启。
删除 service：
kubectl delete service/javaedge-nginx
删除 deployment：
kubectl delete deployment/deployment_name
2 动态扩缩容（弹性伸缩）
扩容
[root@icv-k8s-node-1 ~]# kubectl get allNAME READY STATUS RESTARTS AGE
pod/javaedge-nginx-6996b98cc4-gncwc 1/1 Running 0 13m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/javaedge-nginx 1/1 1 1 3h37m
NAME DESIRED CURRENT READY AGE
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 3h37m
[root@icv-k8s-node-1 ~]# kubectl scale --replicas=2 deployment javaedge-nginx
deployment.apps/javaedge-nginx scaled
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/javaedge-nginx-6996b98cc4-gncwc 1/1 Running 0 13m
pod/javaedge-nginx-6996b98cc4-n4qkk 1/1 Running 0 8s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/javaedge-nginx 2/2 2 2 3h37m
NAME DESIRED CURRENT READY AGE
replicaset.apps/javaedge-nginx-6996b98cc4 2 2 2 3h37m
[root@icv-k8s-node-1 ~]#
当突然高并发时，就能临时扩容。
现在流量平稳了，咱们
缩容
[root@icv-k8s-node-1 ~]# kubectl scale --replicas=1 deployment javaedge-nginx
deployment.apps/javaedge-nginx scaled
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/javaedge-nginx-6996b98cc4-gncwc 1/1 Running 0 16m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/javaedge-nginx 1/1 1 1 3h40m
NAME DESIRED CURRENT READY AGE
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 3h40m
[root@icv-k8s-node-1 ~]#
可见 pod/javaedge-nginx-6996b98cc4-n4qkk被干掉了
删除容器
kubectl get all
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/javaedge-nginx-6996b98cc4-gncwc 1/1 Running 0 21m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/javaedge-nginx 1/1 1 1 3h45m
NAME DESIRED CURRENT READY AGE
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 3h45m
## 删除部署信息，pod也会随之删除
[root@icv-k8s-node-1 ~]# kubectl delete deployment.apps/javaedge-nginx
deployment.apps "javaedge-nginx" deleted
[root@icv-k8s-node-1 ~]# kubectl get all
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
[root@icv-k8s-node-1 ~]#
## 删除service信息
kubectl delete service/javaedge-nginx
3 负载均衡
之前设置那个是节点类型，现在使用集群类型，可以实现负载均衡 port: 集群端口 target-port: 内部nginx 默认端口 ClusterIP: 集群方式，k8s会自动分配一个集群ip。
新建deployment
[root@icv-k8s-node-1 ~]# kubectl create deployment edge-nginx --image=nginx:1.24.0
deployment.apps/edge-nginx created
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/edge-nginx-6d57745bc8-pgmdk 1/1 Running 0 37s
pod/javaedge-nginx-6996b98cc4-m84s5 1/1 Running 0 7m49s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/javaedge-nginx NodePort 10.109.194.31 <none> 90:31104/TCP 6m50s
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/edge-nginx 1/1 1 1 37s
deployment.apps/javaedge-nginx 1/1 1 1 7m49s
NAME DESIRED CURRENT READY AGE
replicaset.apps/edge-nginx-6d57745bc8 1 1 1 37s
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 7m49s
[root@icv-k8s-node-1 ~]#
端口暴露
[root@icv-k8s-node-1 ~]# kubectl expose deployment edge-nginx --port=88 --target-port=80 --type=ClusterIP
service/edge-nginx exposed
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/edge-nginx-6d57745bc8-pgmdk 1/1 Running 0 77s
pod/javaedge-nginx-6996b98cc4-m84s5 1/1 Running 0 8m29s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/edge-nginx ClusterIP 10.106.187.202 <none> 88/TCP 13s
service/javaedge-nginx NodePort 10.109.194.31 <none> 90:31104/TCP 7m30s
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/edge-nginx 1/1 1 1 77s
deployment.apps/javaedge-nginx 1/1 1 1 8m29s
NAME DESIRED CURRENT READY AGE
replicaset.apps/edge-nginx-6d57745bc8 1 1 1 77s
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 8m29s
[root@icv-k8s-node-1 ~]#
所以啊，不能随便命名。
扩容
[root@icv-k8s-node-1 ~]# kubectl scale --replicas=3 deployment edge-nginx
deployment.apps/edge-nginx scaled
[root@icv-k8s-node-1 ~]# kubectl get all
NAME READY STATUS RESTARTS AGE
pod/edge-nginx-6d57745bc8-dm998 1/1 Running 0 9s
pod/edge-nginx-6d57745bc8-pgmdk 1/1 Running 0 3m57s
pod/edge-nginx-6d57745bc8-zsw9v 1/1 Running 0 9s
pod/javaedge-nginx-6996b98cc4-m84s5 1/1 Running 0 11m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/edge-nginx ClusterIP 10.106.187.202 <none> 88/TCP 2m53s
service/javaedge-nginx NodePort 10.109.194.31 <none> 90:31104/TCP 10m
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 21h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/edge-nginx 3/3 3 3 3m57s
deployment.apps/javaedge-nginx 1/1 1 1 11m
NAME DESIRED CURRENT READY AGE
replicaset.apps/edge-nginx-6d57745bc8 3 3 3 3m57s
replicaset.apps/javaedge-nginx-6996b98cc4 1 1 1 11m
[root@icv-k8s-node-1 ~]# curl http://10.106.187.202:88/
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
[root@icv-k8s-node-1 ~]#
nginx返回都一样的，如何测试实现了负载均衡呢？我们来通过 k8s（而不是 docker 的docker exec -it了）进入容器内部，而 pod 才是 k8s 最小单位，所以进入 pod 的 name 即可：
[root@icv-k8s-node-1 ~]# kubectl exec -it edge-nginx-6d57745bc8-dm998 -- /bin/bash
root@edge-nginx-6d57745bc8-pgmdk:/# cd /usr/share/nginx/html
root@edge-nginx-6d57745bc8-dm998:/usr/share/nginx/html# apt-get update
root@edge-nginx-6d57745bc8-dm998:/usr/share/nginx/html# apt-get install
root@edge-nginx-6d57745bc8-zsw9v:/usr/share/nginx/html# vim index.html
ctrl+d退出当前 pod，再对其他两个副本同样操作即可。
重新访问集群 ip：
curl http://10.106.187.202:88/
你就会发现打印了不同的 JavaEdge 00x。
注：如果动态扩容，新的nginx节点会自动加入pod，进入负载均衡的效果
4 yml描述文件
前面我们部署操作nginx容器的时候，都是通过敲命令的方式进行的，其实很繁琐，一不小心就会失败。
我们可以通过yaml配置文件来实现容器的部署，不需要再写命令行了。yaml其实就是对象描述文件，我 们把要实现的容器作为一个对象去声明，指定他的相关属性即可。
比如可将：
- 部署deployment作为yaml
- 构建pod作为yaml
- 实现负载均衡作为yaml
- 构建service作为yaml
- ……都可以
通过运行： kubectl apply -f xxx.yaml 可以实现文件中的内容。
apiVersion: apps/v1 ## 同k8s集群版本⼀致，通过kubectl api-versions查看
kind: Deployment ## 本配置⽂件的类型
metadata: ## 元数据，配置的⼀些基本属性和信息
name: nginx-deployment ## 当前 Deployment 的命名
labels: ## 标签，定义⼀个或多个资源，类似于 docker t
app: nginx ## 设置key为app，value为nginx的标签
spec: ## 当前 Deployment 的具体描述，在k8s中的配置
replicas: 2 ## 指定将要部署的应⽤副本数
selector: ## 标签选择器，同上labels
matchLabels: ## 匹配并选择包含标签app:nginx的相关资源
app: nginx
template: ## 使⽤Pod模板
metadata: ## Pod元数据
labels: ## Pod标签选择，选择包含[app:nginx]标签的Po
app: nginx
spec: ## 定义Pod中的容器详细描述
containers: ## 同docker中的容器
- name: my-nginx ## 容器名称
image: nginx:1.24.0 ## 容器所使用的镜像名称及版本号
[root@icv-k8s-node-1 home]# vim ngx-k8s_deployment.yaml
[root@icv-k8s-node-1 home]# kubectl apply -f ngx-k8s_deployment.yaml
deployment.apps/nginx-deployment created
[root@icv-k8s-node-1 home]#
现在想
4.1 缩容到一个咋办？
修改 yaml
副本数改成 1 即可：
apply
[root@icv-k8s-node-1 home]# kubectl apply -f ngx-k8s_deployment.yaml
deployment.apps/nginx-deployment configured
[root@icv-k8s-node-1 home]#
现在 pod 数和副本数都变成 1 了：
[root@icv-k8s-node-1 home]# kubectl expose deployment nginx-deployment --port=88 --target-port=80 --type=NodePort --dry-run -o yaml
W0630 15:27:30.699552 3888 helpers.go:692] --dry-run is deprecated and can be replaced with --dry-run=client.
apiVersion: v1
kind: Service
metadata:
creationTimestamp: null
labels:
app: nginx
name: nginx-deployment
spec:
ports:
- port: 88
protocol: TCP
targetPort: 80
selector:
app: nginx
type: NodePort
status:
loadBalancer: {}
[root@icv-k8s-node-1 home]#
对此，新建一个 yaml：
apiVersion: v1
kind: Service
metadata:
creationTimestamp: null
labels:
app: nginx
name: nginx-deployment
spec:
ports:
- port: 89
protocol: TCP
targetPort: 80
selector:
app: nginx
type: NodePort
status:
loadBalancer: {}
[root@icv-k8s-node-1 home]# kubectl apply -f k8s_ngx_expose.yaml
service/nginx-deployment created
[root@icv-k8s-node-1 home]#
根据该端口访问也没问题：
根据已有 pod 生成对应 yaml
[root@icv-k8s-node-1 home]# kubectl get pod edge-nginx-6d57745bc8-dm998 -o yaml > k8s_ngx_pod.yaml
[root@icv-k8s-node-1 home]# vim k8s_ngx_pod.yaml
[root@icv-k8s-node-1 home]#
如果想先创建 deployment，再创建 service，也可写在一个 yaml 文件里，只要两部分中间用“---”分割即可：
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