从零开始：使用 Kubernetes 部署 Nginx 应用

业界资讯 2023-07-01 14:13:35 阅读次数: 0 
[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。

PlantUML Diagram

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：

在这里插入图片描述

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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