基于Kubernetess集群部署完整示例——Guestbook
目录贴：Kubernetes学习系列
本文依赖环境：Centos7部署Kubernetes集群、基于Kubernetes集群部署skyDNS服务
该示例中，我们将创建一个redis-master、两个redis-slave、三个frontend。其中，slave会实时备份master中数据，frontend会向master中写数据，之后会从slave中读取数据。所有系统间的调用（例如slave找master同步数据；frontend找master写数据；frontend找slave读数据等），采用的是dns方式实现。
1、准备工作
1.1镜像准备
本示例中依赖以下几个镜像，请提前准备好：
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docker.io/redis:latest 1a8a9ee54eb7 registry.access.redhat.com/rhel7/pod-infrastructure:latest 34d3450d733b gcr.io/google_samples/gb-frontend:v3 c038466384ab gcr.io/google_samples/gb-redisslave:v1 5f026ddffa27 |
1.2环境准备
需要一套kubernetes运行环境，及Cluster DNS，如下：
[root@k8s-master ~]# kubectl cluster-info Kubernetes master is running at http://localhost:8080 KubeDNS is running at http://localhost:8080/api/v1/proxy/namespaces/kube-system/services/kube-dns kubernetes-dashboard is running at http://localhost:8080/api/v1/proxy/namespaces/kube-system/services/kubernetes-dashboard To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'. [root@k8s-master ~]# kubectl get componentstatus NAME STATUS MESSAGE ERROR scheduler Healthy ok controller-manager Healthy ok etcd-0 Healthy {"health": "true"} [root@k8s-master ~]# kubectl get nodes NAME STATUS AGE k8s-node-1 Ready 7d k8s-node-2 Ready 7d [root@k8s-master ~]# kubectl get deployment --all-namespaces NAMESPACE NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE kube-system kube-dns 1 1 1 1 5d kube-system kubernetes-dashboard-latest 1 1 1 1 6d [root@k8s-master ~]#
2、运行redis-master
2.1yaml文件
1）redis-master-controller.yaml
apiVersion: v1 kind: ReplicationController metadata: name: redis-master labels: name: redis-master spec: replicas: 1 selector: name: redis-master template: metadata: labels: name: redis-master spec: containers: - name: master image: redis ports: - containerPort: 6379
2）redis-master-service.yaml
apiVersion: v1 kind: Service metadata: name: redis-master labels: name: redis-master spec: ports: # the port that this service should serve on - port: 6379 targetPort: 6379 selector: name: redis-master
2.2创建rc及service
Master上执行：
[root@k8s-master yaml]# kubectl create -f redis-master-controller.yaml replicationcontroller " redis-master" created [root@k8s-master yaml]# kubectl create -f redis-master-service.yaml service " redis-master" created [root@k8s-master yaml]# kubectl get rc NAME DESIRED CURRENT READY AGE redis-master 1 1 1 1d [root@k8s-master yaml]# kubectl get pod NAME READY STATUS RESTARTS AGE redis-master-5wyku 1/1 Running 0 1d
3、运行redis-slave
3.1yaml文件
1）redis-slave-controller.yaml
apiVersion: v1 kind: ReplicationController metadata: name: redis-slave labels: name: redis-slave spec: replicas: 2 selector: name: redis-slave template: metadata: labels: name: redis-slave spec: containers: - name: worker image: gcr.io/google_samples/gb-redisslave:v1 env: - name: GET_HOSTS_FROM value: dns ports: - containerPort: 6379
2）redis-slave-service.yaml
apiVersion: v1 kind: Service metadata: name: redis-slave labels: name: redis-slave spec: ports: - port: 6379 selector: name: redis-slave
3.2创建rc及service
Master上执行：
[root@k8s-master yaml]# kubectl create -f redis-slave-controller.yaml replicationcontroller "redis-slave" created [root@k8s-master yaml]# kubectl create -f redis-slave-service.yaml service "redis-slave" created [root@k8s-master yaml]# kubectl get rc NAME DESIRED CURRENT READY AGE redis-master 1 1 1 1d redis-slave 2 2 2 44m [root@k8s-master yaml]# kubectl get pod NAME READY STATUS RESTARTS AGE redis-master-5wyku 1/1 Running 0 1d redis-slave-7h295 1/1 Running 0 44m redis-slave-r355y 1/1 Running 0 44m
4、运行frontend
4.1yaml文件
1）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: gcr.io/google_samples/gb-frontend:v3 env: - name: GET_HOSTS_FROM value: dns ports: - containerPort: 80
2）frontend-service.yaml
apiVersion: v1 kind: Service metadata: name: frontend labels: name: fronted spec: type: NodePort ports: - port: 80 nodePort: 30001 selector: name: frontend
4.2创建rc及service
Master上执行：
[root@k8s-master yaml]# kubectl create -f frontend-controller.yaml replicationcontroller "frontend" created [root@k8s-master yaml]# kubectl create -f frontend-service.yaml service "frontend" created [root@k8s-master yaml]# kubectl get rc NAME DESIRED CURRENT READY AGE frontend 3 3 3 28m redis-master 1 1 1 1d redis-slave 2 2 2 44m [root@k8s-master yaml]# kubectl get pod NAME READY STATUS RESTARTS AGE frontend-ax654 1/1 Running 0 29m frontend-k8caj 1/1 Running 0 29m frontend-x6bhl 1/1 Running 0 29m redis-master-5wyku 1/1 Running 0 1d redis-slave-7h295 1/1 Running 0 44m redis-slave-r355y 1/1 Running 0 44m [root@k8s-master yaml]# kubectl get service NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE frontend 10.254.93.91 <nodes> 80/TCP 47m kubernetes 10.254.0.1 <none> 443/TCP 7d redis-master 10.254.132.210 <none> 6379/TCP 1d redis-slave 10.254.104.23 <none> 6379/TCP 1h
4.3页面验证
至此，Guestbook已经运行在了kubernetes中了，但是外部是无法通过通过frontend-service的IP10.0.93.91这个IP来进行访问的。Service的虚拟IP是kubernetes虚拟出来的内部网络，在外部网络中是无法寻址到的，这时候就需要增加一层外网到内网的网络转发。我们的示例中采用的是NodePort的方式实现的，之前在创建frontend-service时设置了nodePort: 30001，即kubernetes将会在每个Node上设置端口，成为NodePort，通过NodePort端口可以访问到真正的服务。
