使用Kubernetes建立PHP留言板系统

本文将演示使用kubernetes系统基于 kubeguide相关的镜像文件建立基于php和redis的留言板系统，由于系统资源有限，kubernetes集群只有一个master节点和slave节点。
Docker本地仓库与kubernetes集群配置请查看前文。

1、环境介绍
操做系统版本：centos linux 7.2 64bit
Master节点：192.168.115.5/24 vm1
Slave节点1：192.168.115.6/24 vm2

访问流程图以下：

2、在线下载相关的镜像文件，并归入本地仓库统一管理

# docker pull kubeguide/redis-master # docker pull kubeguide/guestbook-php-frontend # docker pull kubeguide/guestbook-redis-slave # docker tag kubeguide/redis-master registry.fjhb.cn/redis-master # docker tag kubeguide/guestbook-php-frontend registry.fjhb.cn/guestbook-php-frontend # docker tag kubeguide/guestbook-redis-slave registry.fjhb.cn/guestbook-redis-slave # docker push registry.fjhb.cn/redis-master # docker push registry.fjhb.cn/guestbook-php-frontend # docker push registry.fjhb.cn/guestbook-redis-slave # curl -u yang:123 -XGET https://registry.fjhb.cn/v2/_catalog # docker images |grep fjhb

3、配置文件准备
一、建立redis-master rc和service配置文件

# cat redis-master-controller.yaml apiVersion: v1 kind: ReplicationController metadata: name: redis-master spec: replicas: 1 selector: name: redis-master template: metadata: name: redis-master labels: name: redis-master spec: containers: - name: redis-master image: registry.fjhb.cn/redis-master ports: - containerPort: 6379

# cat redis-master-service.yaml apiVersion: v1 kind: Service metadata: name: redis-master labels: name: redis-master spec: ports: - port: 6379 targetPort: 6379 selector: name: redis-master

二、建立redis-slave的rc和service配置文件

# cat redis-slave-controller.yaml apiVersion: v1 kind: ReplicationController metadata: name: redis-slave spec: replicas: 2 selector: name: redis-slave template: metadata: name: redis-slave labels: name: redis-slave spec: containers: - name: redis-slave image: registry.fjhb.cn/guestbook-redis-slave env: - name: GET_HOSTS_FROM value: env ports: - containerPort: 6379

# cat redis-slave-service.yaml apiVersion: v1 kind: Service metadata: name: redis-slave labels: name: redis-slave spec: ports: - port: 6379 selector: name: redis-slave

三、建立frontend的rc和service配置文件

# cat frontend-controller.yaml apiVersion: v1 kind: ReplicationController metadata: name: frontend labels: name: frontend spec: replicas: 3 selector: name: frontend template: metadata: labels: name: frontend spec: containers: - name: frontend image: registry.fjhb.cn/guestbook-php-frontend env: - name: GET_HOSTS_FROM value: env ports: - containerPort: 80

# cat frontend-service.yaml apiVersion: v1 kind: Service metadata: name: frontend labels: name: frontend spec: type: NodePort ports: - port: 80 nodePort: 30001 selector: name: frontend

4、在master节点上建立rc 和 sevices

# kubectl create -f redis-master-controller.yaml # kubectl create -f redis-slave-controller.yaml # kubectl create -f frontend-controller.yaml # kubectl create -f redis-master-service.yaml # kubectl create -f redis-slave-service.yaml # kubectl create -f frontend-service.yaml # kubectl get rc # kubectl get svc # kubectl get pod

# kubectl describe pod redis-slave-gsk1p

没法建立pod的缘由主要是没法从本地仓库中拉取镜像，即便本地已经存在了这个镜像，也是报这个错误。由于kubernetes的imagePullPolicy获取镜像策略默认值为Always

咱们本地仓库的nginx配置了basic验证，故而报错以下
Error syncing pod, skipping: failed to "StartContainer" for "redis-slave" with ErrImagePull: "unauthorized: authentication required"
关闭nginx basic认证以后，再尝试一次，果真没有问题。

在Kubernetes中使用私有仓库并支持basic认证的最终解决方案是去配置kubernetes的serviceaccount，关于详细的配置将在后续的文章中进行介绍。

6、测试
一、查看redis master节点的redis集群信息

# kubectl exec redis-master-9993n redis-cli info |grep -A 5 "Replication" # kubectl exec redis-slave-gnq41 redis-cli info |grep -A 5 "Replication" # kubectl exec redis-slave-nvscp redis-cli info |grep -A 5 "Replication" 

二、web测试

经过firebug插件能够看到是php+apache在提供web服务

7、 rc和service的删除

来自：http://blog.51cto.com/ylw6006/2067250# kubectl delete -f frontend-controller.yaml # kubectl delete -f redis-master-controller.yaml # kubectl delete -f redis-slave-controller.yaml # kubectl delete -f redis-slave-service.yaml # kubectl delete -f redis-master-service.yaml # kubectl delete -f frontend-service.yaml