从零开始：使用 Kubernetes 部署 Nginx 应用

梦里梦外; 2024-03-17 13:08 12阅读 0赞

[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：

![af109812cd79416ca16d02e104e26a55.png][]

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

![004c62d36c7b4026b1fab211b527cd99.png][]

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]#

![cd27da2d2bf240138f9e801827bb3dae.png][]

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][775c6a3b317b4e908af7794f0fb74a42.png]

##### 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：

![5ac7ffbe6307440092be12fff8612b19.png][]

[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]#

![50ed503c8c8f4b07af28fc895f7bb97c.png][]

根据该端口访问也没问题：

![68028769fb964f06a2504dbccd4a8627.png][]

#### 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：

![cf7e97ebc1cf4ba09e0de65a38df9c88.png][]

[PlantUML Diagram]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/ca20c278ed6046d1aec370f6ebb079ed.png
[af109812cd79416ca16d02e104e26a55.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/ff70d900828e4fd696963e1427012923.png
[004c62d36c7b4026b1fab211b527cd99.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/d52001eba37641c39c94aa774b5751f3.png
[cd27da2d2bf240138f9e801827bb3dae.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/738479e9b9fa404bb4baacd6e2b2a247.png
[775c6a3b317b4e908af7794f0fb74a42.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/8385ab5ea632425490ded7010f735af8.png
[5ac7ffbe6307440092be12fff8612b19.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/fab6241f69804b439d1582c0e89ec2fe.png
[50ed503c8c8f4b07af28fc895f7bb97c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/bb8ed8bb49d84d5f80a48d9576af2908.png
[68028769fb964f06a2504dbccd4a8627.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/cab2d02a2f634eb8961ee7a7b31c768e.png
[cf7e97ebc1cf4ba09e0de65a38df9c88.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/cfac43ece1194e8aae67635adf4d3e81.png