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kubernetes 1.3.1 guestbook(php frontend with redis cluster)

16 Jan 2018

0. Objectives

启动redis master
启动redis slave
启动guestbook前端
公开并查看前端service
清除工作

参考链接：kubenetes 官方文档

执行以下操作之前，可以参照文档先创建一个kubenetes cluster

1. Start up the Redis Master

1) Creating the Redis Master Deployment

redis-master-deployment.yaml

apiVersion: apps/v1beta2 # for versions before 1.8.0 use apps/v1beta1
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

通过selector中的mathLabels和pod的labels匹配联系在一起

kubectl apply -f redis-master-deployment.yaml

kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
redis-master-585798d8ff-lqw5t   1/1       Running   0          19m

kubectl logs -f redis-master-585798d8ff-lqw5t

2) Creating the Redis Master Service

redis-master-service.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

通过selector和pod的labels匹配联系在一起

kubectl apply -f redis-master-service.yaml

kubectl get service
NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
kubernetes     ClusterIP   10.254.0.1       <none>        443/TCP    1d
redis-master   ClusterIP   10.254.184.211   <none>        6379/TCP   6s

2. Start up the Redis Slaves

创建Redis slave来组成redis集群

1) Creating the Redis Slave Deployment

redis-slave-deployment.yaml

apiVersion: 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: env
        ports:
        - containerPort: 6379

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

redis slave 是通过下面的命令来和redis-master这个service建立的连接
if [[ ${GET_HOSTS_FROM:-dns} == "env" ]]; then
  redis-server --slaveof ${REDIS_MASTER_SERVICE_HOST} 6379
else
  redis-server --slaveof redis-master 6379
fi

kubectl apply -f redis-slave-deployment.yaml

kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
redis-master-585798d8ff-lqw5t   1/1       Running   0          35m
redis-slave-865486c9df-254jt    1/1       Running   0          6m
redis-slave-865486c9df-qczr9    1/1       Running   0          6m

2) Creating the Redis Slave Service

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

kubectl apply -f redis-slave-service.yaml

kubectl get services
NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
kubernetes     ClusterIP   10.254.0.1       <none>        443/TCP    1d
redis-master   ClusterIP   10.254.184.211   <none>        6379/TCP   18m
redis-slave    ClusterIP   10.254.251.186   <none>        6379/TCP   5s

3. Set up and Expose the Guestbook Frontend

guestbook应用是用php编写的一个处理http请求的web前端程序，调用redis-master（写）和redis-slave（读）。

1) Creating the Guestbook Frontend Deployment

frontend-deployment.yaml

apiVersion: 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: env
        ports:
        - containerPort: 80

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

kubectl apply -f frontend-deployment.yaml

kubectl get pods -l app=guestbook -l tier=frontend
NAME                        READY     STATUS    RESTARTS   AGE
frontend-656ff8f48f-4zt9q   1/1       Running   0          18m
frontend-656ff8f48f-gfz5w   1/1       Running   0          18m
frontend-656ff8f48f-qvhwk   1/1       Running   0          18m

2) Creating the Frontend Service

frontend-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: frontend
  labels:
    app: guestbook
    tier: frontend
spec:
  type: NodePort
  ports:
  - port: 80
  selector:
    app: guestbook
    tier: frontend

comment or delete type: NodePort if you want to use a LoadBalancer
if your cluster supports it, uncomment the following to automatically create
an external load-balanced IP for the frontend service.
type: LoadBalancer

frontend是通过guestbook.php中的$host = 'redis-slave'和$host = 'redis-master'来和redis建立的联系

kubectl apply -f frontend-service.yaml

kubectl get services
NAME           TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
frontend       NodePort    10.254.217.166   <none>        80:40751/TCP   5s
kubernetes     ClusterIP   10.254.0.1       <none>        443/TCP        1d
redis-master   ClusterIP   10.254.184.211   <none>        6379/TCP       46m
redis-slave    ClusterIP   10.254.251.186   <none>        6379/TCP       28m

3) Viewing the Frontend Service via NodePort

kubectl get services frontend
NAME       TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
frontend   NodePort   10.254.217.166   <none>        80:40751/TCP   4m

因为我们是使用的NodePort方式转发的service，所以我们只需要在浏览器中访问cluster中的任意一个node ip:40751就可以了

4. Cleaning up

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

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