Start up the Redis Master 啟動Redis Master

Creating the Redis Master Deployment

The manifest file, included below, specifies a Deployment controller that runs a single replica Redis master Pod.

cat EOF << redis-master-deployment.yaml 
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: redis-master
  labels:
    app: redis
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: redis
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
        ports:
        - containerPort: 6379

Query the list of Pods to verify that the Redis Master Pod is running:
查詢Pod列表央串，以驗證Redis主Pod正在運行

kubectl get pods

The response should be similar to this:
答復應類似于

NAME                            READY     STATUS    RESTARTS   AGE
  redis-master-1068406935-3lswp   1/1       Running   0          28s

Run the following command to view the logs from the Redis Master Pod:
運行以下命令從Redis主Pod查看日志:

kubectl logs -f POD-NAME

Creating the Redis Master Service

cat EOF <<< 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

Apply the Redis Master Service from the following redis-master-service.yaml file:

kubectl apply -f redis-master-service.yaml

Query the list of Services to verify that the Redis Master Service is running:

kubectl get service

The response should be similar to this:

  NAME           TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)    AGE
  kubernetes     ClusterIP   10.0.0.1     <none>        443/TCP    1m
  redis-master   ClusterIP   10.0.0.151   <none>        6379/TCP   8s

Note: This manifest file creates a Service named redis-master with a set of labels that match the labels previously defined, so the Service routes network traffic to the Redis master Pod.
此清單文件創(chuàng)建一個名為Redis -master的服務蹄咖，其中包含一組與前面定義的標簽相匹配的標簽颊亮，因此服務將網絡流量路由到Redis主Pod铆农。

Start up the Redis Slaves

Creating the Redis Slave Deployment

Deployments scale based off of the configurations set in the manifest file. In this case, the Deployment object specifies two replicas.

部署規(guī)模基于清單文件中設置的配置撬码。在本例中膘壶，部署對象指定兩個副本。

cat EOF <<<>application/guestbook/redis-slave-deployment.yaml
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: redis-slave
  labels:
    app: redis
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: redis
        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
          # 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

Apply the Redis Slave Deployment from the redis-slave-deployment.yaml file:

kubectl apply -f https://k8s.io/examples/application/guestbook/redis-slave-deployment.yaml

Query the list of Pods to verify that the Redis Slave Pods are running:

kubectl get pods

The response should be similar to this:

  NAME                            READY     STATUS              RESTARTS   AGE
  redis-master-1068406935-3lswp   1/1       Running             0          1m
  redis-slave-2005841000-fpvqc    0/1       ContainerCreating   0          6s
  redis-slave-2005841000-phfv9    0/1       ContainerCreating   0          6s

Creating the Redis Slave Service
The guestbook application needs to communicate to Redis slaves to read data. To make the Redis slaves discoverable, you need to set up a Service. A Service provides transparent load balancing to a set of Pods.

application/guestbook/redis-slave-service.yaml Copy application/guestbook/redis-slave-service.yaml to clipboard
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
```Apply the Redis Slave Service from the following redis-slave-service.yaml file:

kubectl apply -f redis-slave-service.yaml

Query the list of Services to verify that the Redis slave service is running:

kubectl get services

The response should be similar to this:
響應內容大致如下

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 2m
redis-master ClusterIP 10.0.0.151 <none> 6379/TCP 1m
redis-slave ClusterIP 10.0.0.223 <none> 6379/TCP 6s

## Set up and Expose the Guestbook Frontend

### Creating the Guestbook Frontend Deployment

cat EOF <<< application/guestbook/frontend-deployment.yaml
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
name: frontend
labels:
app: guestbook
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
# 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
EOF

Apply the frontend Deployment from the frontend-deployment.yaml file:

kubectl apply -f frontend-deployment.yaml

Query the list of Pods to verify that the three frontend replicas are running:

kubectl get pods -l app=guestbook -l tier=frontend

The response should be similar to this:

NAME READY STATUS RESTARTS AGE
frontend-3823415956-dsvc5 1/1 Running 0 54s
frontend-3823415956-k22zn 1/1 Running 0 54s
frontend-3823415956-w9gbt 1/1 Running 0 54s

### Creating the Frontend Service

The redis-slave and redis-master Services you applied are only accessible within the container cluster because the default type for a Service is ClusterIP.

 ClusterIP provides a single IP address for the set of Pods the Service is pointing to. This IP address is accessible only within the cluster.

您應用的redis-slave和redis-master服務只能在容器集群中訪問剂邮，因為服務的默認類型是ClusterIP摇幻。

ClusterIP為服務指向的一組pod提供一個IP地址，這個IP地址只能在集群中訪問挥萌。


If you want guests to be able to access your guestbook, you must configure the frontend Service to be externally visible, so a client can request the Service from outside the container cluster. 

Minikube can only expose Services through NodePort.

如果您希望客人能夠訪問您的來賓簿绰姻，您必須將前端服務配置為外部可見的，以便客戶端可以從容器集群外部請求服務引瀑。

Minikube只能通過NodePort公開服務狂芋。

本例使用LoadBalancer公開服務

Note: Some cloud providers, like Google Compute Engine or Google Kubernetes Engine, support external load balancers. If your cloud provider supports load balancers and you want to use it, simply delete or comment out type: NodePort, and uncomment type: LoadBalancer.

application/guestbook/frontend-service.yaml Copy application/guestbook/frontend-service.yaml to clipboard
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

Apply the frontend Service from the frontend-service.yaml file:

  kubectl apply -f https://k8s.io/examples/application/guestbook/frontend-service.yaml
Query the list of Services to verify that the frontend Service is running:

kubectl get services

The response should be similar to this:

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend NodePort 10.0.0.112 <none> 80:31323/TCP 6s
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 4m
redis-master ClusterIP 10.0.0.151 <none> 6379/TCP 2m
redis-slave ClusterIP 10.0.0.223 <none> 6379/TCP 1m

Viewing the Frontend Service via NodePort
If you deployed this application to Minikube or a local cluster, you need to find the IP address to view your Guestbook.

Run the following command to get the IP address for the frontend Service.

minikube service frontend --url

The response should be similar to this:

http://192.168.99.100:31323

Copy the IP address, and load the page in your browser to view your guestbook.

Viewing the Frontend Service via LoadBalancer
If you deployed the frontend-service.yaml manifest with type: LoadBalancer you need to find the IP address to view your Guestbook.

Run the following command to get the IP address for the frontend Service.

kubectl get service frontend

The response should be similar to this:

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend ClusterIP 10.51.242.136 109.197.92.229 80:32372/TCP 1m

Copy the external IP address, and load the page in your browser to view your guestbook.

### Scale the Web Frontend
Scaling up or down is easy because your servers are defined as a Service that uses a Deployment controller.

Run the following command to scale up the number of frontend Pods:

kubectl scale deployment frontend --replicas=5

Query the list of Pods to verify the number of frontend Pods running:

kubectl get pods

The response should look similar to this:

NAME READY STATUS RESTARTS AGE
frontend-3823415956-70qj5 1/1 Running 0 5s
frontend-3823415956-dsvc5 1/1 Running 0 54m
frontend-3823415956-k22zn 1/1 Running 0 54m
frontend-3823415956-w9gbt 1/1 Running 0 54m
frontend-3823415956-x2pld 1/1 Running 0 5s
redis-master-1068406935-3lswp 1/1 Running 0 56m
redis-slave-2005841000-fpvqc 1/1 Running 0 55m
redis-slave-2005841000-phfv9 1/1 Running 0 55m

Run the following command to scale down the number of frontend Pods:

  kubectl scale deployment frontend --replicas=2
Query the list of Pods to verify the number of frontend Pods running:

kubectl get pods

The response should look similar to this:

NAME READY STATUS RESTARTS AGE
frontend-3823415956-k22zn 1/1 Running 0 1h
frontend-3823415956-w9gbt 1/1 Running 0 1h
redis-master-1068406935-3lswp 1/1 Running 0 1h
redis-slave-2005841000-fpvqc 1/1 Running 0 1h
redis-slave-2005841000-phfv9 1/1 Running 0 1h

### Cleaning up

Deleting the Deployments and Services also deletes any running Pods. Use labels to delete multiple resources with one command.

刪除部署和服務也會刪除任何正在運行的pod。使用標簽用一個命令刪除多個資源憨栽。

Run the following commands to delete all Pods, Deployments, and Services.

運行以下命令刪除所有pod帜矾、部署和服務辆影。

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

The responses should be:
響應應該是:

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

Query the list of Pods to verify that no Pods are running:
查詢Pods列表，確認吊Pods沒有運行:

kubectl get pods

The response should be this:

No resources found.