在Kubernetes集群中使用Redis部署PHP留言簿应用程序

悠悠 2022-05-31 04:07 171阅读 0赞

# 在Kubernetes集群中使用Redis部署PHP留言簿应用 #

> 本教程介绍如何构建和部署使用Kubernetes和一个简单的，多层次的Web应用程序Guestbook  
> 参考教程：[https://kubernetes.io/docs/tutorials/stateless-application/guestbook/][https_kubernetes.io_docs_tutorials_stateless-application_guestbook]

![这里写图片描述][SouthEast]

## 实验目标 ##

*  启动一个Redis Master
 *  启动一个Redis Slave
 *  启动guestbook程序
 *  展示和查看前端服务
 *  清理

## 实验环境 ##

> 需要有一个Kubernetes集群，以及kubectl命令行工具必须配置与集群通信

*  参考：[http://mp.blog.csdn.net/mdeditor/index/79209551][http_mp.blog.csdn.net_mdeditor_index_79209551]

> 在此可以检查k8s及相关工具版本：**`kubectl version`**

[root@aniu-k8s ~]# kubectl version
    Client Version: version.Info{ Major:"1", Minor:"9", GitVersion:"v1.9.2", GitCommit:"5fa2db2bd46ac79e5e00a4e6ed24191080aa463b", GitTreeState:"clean", BuildDate:"2018-01-18T10:09:24Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}
    Server Version: version.Info{ Major:"1", Minor:"9", GitVersion:"v1.9.2", GitCommit:"5fa2db2bd46ac79e5e00a4e6ed24191080aa463b", GitTreeState:"clean", BuildDate:"2018-01-18T09:42:01Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}

> 下载实验用到的配置文件：

*  [redis-master-deployment.yaml][]
 *  [redis-master-service.yaml][]
 *  [redis-slave-deployment.yaml][]
 *  [redis-slave-service.yaml][]
 *  [frontend-deployment.yaml][]
 *  [frontend-service.yaml][]

> 笔者在k8s集群master服务器上创建了/opt/k8s/guestbook目录，下载上面的文件到目录如下：

[root@aniu-k8s ~]# cd /opt/k8s/guestbook/
    [root@aniu-k8s guestbook]# ll
    total 24
    -rw-r--r-- 1 root root 1086 Feb  6 16:28 frontend-deployment.yaml
    -rw-r--r-- 1 root root  438 Feb  6 16:29 frontend-service.yaml
    -rw-r--r-- 1 root root  561 Feb  6 17:01 redis-master-deployment.yaml
    -rw-r--r-- 1 root root  233 Feb  6 17:14 redis-master-service.yaml
    -rw-r--r-- 1 root root 1117 Feb  6 16:28 redis-slave-deployment.yaml
    -rw-r--r-- 1 root root  209 Feb  6 16:28 redis-slave-service.yaml

## 启动Redis Master ##

> 留言簿应用程序使用Redis来存储其数据。它将其数据写入Redis主实例，并从多个Redis从实例中读取数据

### 创建Redis Master部署配置文件 ###

> 清单文件（如下所示）指定运行单个副本Redis master Pod的Deployment Controller。

*  在下载清单文件的目录中启动一个终端窗口
 *  从`redis-master-deployment.yaml`文件应用Redis Master部署：

[root@aniu-k8s guestbook]# kubectl apply -f redis-master-deployment.yaml
    Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
    deployment "redis-master" configured

*  redis-master-deployment.yaml

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
    kind: Deployment
    metadata:
      name: redis-master
    spec:
      selector:
        matchLabels:
          app: redis
          role: master
          tier: backend
      replicas: 1
      template:
        metadata:
          labels:
            app: redis
            role: master
            tier: backend
        spec:
          containers:
          - name: master
            image: k8s.gcr.io/redis:e2e  # or just image: redis
            resources:
              requests:
                cpu: 100m
                memory: 100Mi
            ports:
            - containerPort: 6379

*  查询Pod的列表以验证Redis Master Pod正在运行

[root@aniu-k8s guestbook]# kubectl get pods
    NAME                            READY     STATUS    RESTARTS   AGE
    redis-master-585798d8ff-g69wc   1/1       Running   0          28m

*  运行以下命令查看Redis Master Pod中的日志:

[root@aniu-k8s guestbook]# kubectl logs -f redis-master-585798d8ff-g69wc
                    _._                                                  
               _.-``__ ''-._                                             
          _.-``    `. `_.  ''-._           Redis 2.8.19 (00000000/0) 64 bit
      .-`` .-```. ```\/    _.,_ ''-._                                   
     (    ' , .-` | `, ) Running in stand alone mode |`-._`-...-` __...-.``-._|'` _.-'| Port: 6379 | `-._   `._ / _.-' | PID: 1 `-._    `-._ `-./  _.-' _.-'                                   
     |`-._`-._    `-.__.-' _.-'_.-'| | `-._`-._ _.-'_.-' | http://redis.io `-._    `-._`-.__.-'_.-'    _.-' |`-._`-._ `-.__.-'    _.-'_.-'|                                  
     |    `-._`-._        _.-'_.-'    |                                  
      `-._ `-._`-.__.-'_.-' _.-' `-._    `-.__.-' _.-' `-._        _.-' `-.__.-'                                               
    [1] 06 Feb 09:14:33.096 # Server started, Redis version 2.8.19
    [1] 06 Feb 09:14:33.097 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
    [1] 06 Feb 09:14:33.097 * The server is now ready to accept connections on port 6379

### 创建Redis Master服务 ###

> 留言簿应用程序需要与Redis主站通信以写入其数据。您需要应用服务将流量代理到Redis主Pod。服务定义访问Pod的策略

*  应用以下`redis-master-service.yaml`文件中的Redis Master服务：

[root@aniu-k8s guestbook]# kubectl apply -f redis-master-service.yaml
    service "redis-master" created

*  redis-master-service.yaml

*  查询服务列表以验证Redis主服务正在运行：

[root@aniu-k8s guestbook]# kubectl get service
    NAME           TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
    kubernetes     ClusterIP   10.96.0.1       <none>        443/TCP    6d
    redis-master   ClusterIP   10.109.193.22   <none>        6379/TCP   6s

## 启动Redis Slaves服务 ##

> 虽然Redis master是一个单独的pod，但是可以通过添加副本Redis Slaves来使其高度可用以满足流量需求

### 创建Redis Slaves部署 ###

> 部署根据清单文件中设置的配置进行缩放。在这种情况下，Deployment对象指定两个副本
> 
> 如果没有任何副本正在运行，则此部署将在您的容器群集上启动两个副本。相反，如果有两个以上的副本正在运行，则会缩小直到两个副本正在运行

*  从`redis-slave-deployment.yaml`文件应用Redis Slave部署：

[root@aniu-k8s guestbook]# kubectl apply -f redis-slave-deployment.yaml
    deployment "redis-slave" created

*  redis-slave-deployment.yaml

apiVersion: v1
    kind: Service
    metadata:
      name: redis-master
      labels:
        app: redis
        role: master
        tier: backend
    spec:
      ports:
      - port: 6379
        targetPort: 6379
      selector:
        app: redis
        role: master
        tier: backend
    [root@aniu-k8s guestbook]# cat redis-slave-deployment.yaml 
    apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
    kind: Deployment
    metadata:
      name: redis-slave
    spec:
      selector:
        matchLabels:
          app: redis
          role: slave
          tier: backend
      replicas: 2
      template:
        metadata:
          labels:
            app: redis
            role: slave
            tier: backend
        spec:
          containers:
          - name: slave
            image: gcr.io/google_samples/gb-redisslave:v1
            resources:
              requests:
                cpu: 100m
                memory: 100Mi
            env:
            - name: GET_HOSTS_FROM
              value: dns
              # Using `GET_HOSTS_FROM=dns` requires your cluster to
              # provide a dns service. As of Kubernetes 1.3, DNS is a built-in
              # service launched automatically. However, if the cluster you are using
              # does not have a built-in DNS service, you can instead
              # instead access an environment variable to find the master
              # service's host. To do so, comment out the 'value: dns' line above, and
              # uncomment the line below:
              # value: env
            ports:
            - containerPort: 6379

*  查询Pod的列表以验证Redis Slave Pod是否正在运行：

[root@aniu-k8s guestbook]# kubectl get pods
    NAME                            READY     STATUS              RESTARTS   AGE
    redis-master-585798d8ff-g69wc   1/1       Running             0          3m
    redis-slave-865486c9df-tjvfn    0/1       ContainerCreating   0          27s
    redis-slave-865486c9df-x76gb    1/1       Running

### 创建Redis Slave服务 ###

> 留言簿应用程序需要与Redis Slave进行通信以读取数据。为了使Redis Slave可以被发现，需要建立一个服务。服务为一组Pod提供透明的负载平衡。

*  应用以下`redis-slave-service.yaml`文件中的Redis从服务

[root@aniu-k8s guestbook]# kubectl apply -f redis-slave-service.yaml
    service "redis-slave" created

*  redis-slave-service.yaml

apiVersion: v1
    kind: Service
    metadata:
      name: redis-slave
      labels:
        app: redis
        role: slave
        tier: backend
    spec:
      ports:
      - port: 6379
      selector:
        app: redis
        role: slave
        tier: backend

*  查询服务列表以验证Redis Slave服务是否正在运行

[root@aniu-k8s guestbook]# kubectl get services
    NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
    kubernetes     ClusterIP   10.96.0.1        <none>        443/TCP    6d
    redis-master   ClusterIP   10.109.193.22    <none>        6379/TCP   2m
    redis-slave    ClusterIP   10.101.252.227   <none>        6379/TCP   21s

## 设置和公开留言簿前端 ##

> 留言簿应用程序有一个Web前端，用于使用PHP编写的HTTP请求。它被配置为连接到redis-master服务的写请求和redis-slave服务的读请求

### 创建留言簿前端部署 ###

*  从以下`frontend-deployment.yaml`文件应用前端部署：

[root@aniu-k8s guestbook]# kubectl apply -f frontend-deployment.yaml
    deployment "frontend" created

*  frontend-deployment.yaml

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
    kind: Deployment
    metadata:
      name: frontend
    spec:
      selector:
        matchLabels:
          app: guestbook
          tier: frontend
      replicas: 3
      template:
        metadata:
          labels:
            app: guestbook
            tier: frontend
        spec:
          containers:
          - name: php-redis
            image: gcr.io/google-samples/gb-frontend:v4
            resources:
              requests:
                cpu: 100m
                memory: 100Mi
            env:
            - name: GET_HOSTS_FROM
              value: dns
              # Using `GET_HOSTS_FROM=dns` requires your cluster to
              # provide a dns service. As of Kubernetes 1.3, DNS is a built-in
              # service launched automatically. However, if the cluster you are using
              # does not have a built-in DNS service, you can instead
              # instead access an environment variable to find the master
              # service's host. To do so, comment out the 'value: dns' line above, and
              # uncomment the line below:
              # value: env
            ports:
            - containerPort: 80

*  查询Pod的列表以验证三个前端副本正在运行：

[root@aniu-k8s guestbook]# kubectl get pods -l app=guestbook -l tier=frontend
    NAME                       READY     STATUS    RESTARTS   AGE
    frontend-67f65745c-lr25s   1/1       Running   0          1m
    frontend-67f65745c-n798g   1/1       Running   0          1m
    frontend-67f65745c-n92r4   1/1       Running   0          1m

### 创建前端服务 ###

> 应用的redis-slave和redis-master服务只能在容器群集内访问，因为服务的默认类型是ClusterIP。 ClusterIP为服务指向的一组Pod提供一个IP地址。 该IP地址只能在群集内访问。
> 
> 如果希望guest虚拟机能够访问您的留言簿，则必须将前端服务配置为外部可见，以便客户端可以从容器群集外部请求该服务。 `Minikube`只能通过`NodePort`公开服务

*  应用以下`frontend-service.yaml`文件中的前端服务

[root@aniu-k8s guestbook]# kubectl apply -f frontend-service.yaml
    service "frontend" created

*  frontend-service.yaml

apiVersion: v1
    kind: Service
    metadata:
      name: frontend
      labels:
        app: guestbook
        tier: frontend
    spec:
      # comment or delete the following line if you want to use a LoadBalancer
      type: NodePort 
      # if your cluster supports it, uncomment the following to automatically create
      # an external load-balanced IP for the frontend service.
      # type: LoadBalancer
      ports:
      - port: 80
      selector:
        app: guestbook
        tier: frontend

*  查询服务列表以验证前端服务正在运行

[root@aniu-k8s guestbook]# kubectl get services 
    NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
    frontend       NodePort    10.103.1.159     <none>        80:31546/TCP   7s
    kubernetes     ClusterIP   10.96.0.1        <none>        443/TCP        6d
    redis-master   ClusterIP   10.109.193.22    <none>        6379/TCP       5m
    redis-slave    ClusterIP   10.101.252.227   <none>        6379/TCP       4m

### 通过NodePort查看前端服务 ###

> 如果您将此应用程序部署到Minikube或本地群集，则需要查找IP地址才能查看您的留言簿。

*  行以下命令获取前端服务的IP地址

minikube service frontend --url

> 复制IP地址，然后在浏览器中加载页面以查看您的留言簿。

### 通过LoadBalancer查看前端服务 ###

*  运行以下命令获取前端服务的IP地址

[root@aniu-k8s guestbook]# kubectl get service frontend

> 复制外部IP地址，并在浏览器中加载页面以查看您的留言簿

## 扩展Web前端 ##

> 放大或缩小很容易，因为我们的服务器被定义为使用部署控制器的服务

*  运行以下命令以放大前端Pod的数量

[root@aniu-k8s guestbook]# kubectl scale deployment frontend --replicas=5
    deployment "frontend" scaled

*  查询Pod的列表以验证正在运行的前端Pod的数量：

[root@aniu-k8s guestbook]# kubectl get pods
    NAME                            READY     STATUS    RESTARTS   AGE
    frontend-67f65745c-lr25s        1/1       Running   0          5m
    frontend-67f65745c-n798g        1/1       Running   0          5m
    frontend-67f65745c-n92r4        1/1       Running   0          5m
    frontend-67f65745c-nsnfs        1/1       Running   0          7s
    frontend-67f65745c-spjnm        1/1       Running   0          7s
    redis-master-585798d8ff-g69wc   1/1       Running   0          10m
    redis-slave-865486c9df-tjvfn    1/1       Running   0          8m
    redis-slave-865486c9df-x76gb    1/1       Running   0          8m

*  运行以下命令以缩小前端Pod的数量：

[root@aniu-k8s guestbook]# kubectl scale deployment frontend --replicas=2
    deployment "frontend" scaled
    [root@aniu-k8s guestbook]# kubectl get pods
    NAME                            READY     STATUS        RESTARTS   AGE
    frontend-67f65745c-lr25s        1/1       Running       0          50m
    frontend-67f65745c-n798g        1/1       Running       0          50m
    frontend-67f65745c-n92r4        0/1       Terminating   0          50m
    frontend-67f65745c-spjnm        0/1       Terminating   0          45m
    redis-master-585798d8ff-g69wc   1/1       Running       0          56m
    redis-slave-865486c9df-tjvfn    1/1       Running       0          53m
    redis-slave-865486c9df-x76gb    1/1       Running       0          53m

## 清理pods及services ##

> 删除部署和服务也会删除任何正在运行的Pod。使用标签可以用一个命令删除多个资源。

*  运行以下命令删除所有Pod，Deployments和Services。

kubectl delete deployment -l app=redis
    kubectl delete service -l app=redis
    kubectl delete deployment -l app=guestbook
    kubectl delete service -l app=guestbook

*  回显如下：

deployment "redis-master" deleted
    deployment "redis-slave" deleted
    service "redis-master" deleted
    service "redis-slave" deleted
    deployment "frontend" deleted    
    service "frontend" deleted

*  查询Pod的列表以验证没有Pod正在运行：

kubectl get pods
    # 
    No resources found.

[https_kubernetes.io_docs_tutorials_stateless-application_guestbook]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/
[SouthEast]: /images/20220531/751140281135464a864db249be5ed7db.png
[http_mp.blog.csdn.net_mdeditor_index_79209551]: http://mp.blog.csdn.net/mdeditor/index/79209551
[redis-master-deployment.yaml]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-master-deployment.yaml
[redis-master-service.yaml]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-master-service.yaml
[redis-slave-deployment.yaml]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-slave-deployment.yaml
[redis-slave-service.yaml]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-slave-service.yaml
[frontend-deployment.yaml]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/frontend-deployment.yaml
[frontend-service.yaml]: https://kubernetes.io/docs/tutorials/stateless-application/guestbook/frontend-service.yaml