本頁展示如何使用Kubernetes部署物件（Kubernetes Deployment object）執行一個應用程式。

目標

• 建立一個nginx部署。
• 使用kubectl列出關於部署的資訊。
• 更新部署。

準備工作

您需要有一個Kubernetes叢集，並且必須配置kubectl命令列工具來與您的叢集通訊。如果您還沒有叢集，您可以使用Minikube建立一個叢集，或者您可以使用這些Kubernetes平臺:

您的Kubernetes伺服器版本必須是v1.9。檢視版本，請輸入kubectl version。

建立和體驗nginx部署

您可以通過建立Kubernetes部署物件來執行應用程式，還可以在YAML檔案中描述部署。例如，通過YAML檔案描述了一個執行nginx:1.7.9 Docker映象的部署:

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2 # tells deployment to run 2 pods matching the template
  template: # create pods using pod definition in this template
 

    metadata:
      # unlike pod-nginx.yaml, the name is not included in the meta data as a unique name is
      # generated from the deployment name
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort
 
: 80

1. 基於YAML檔案建立部署:

   kubectl apply -f https://k8s.io/docs/tasks/run-application/deployment.yaml
   

2. 顯示部署的相關資訊:

   kubectl describe deployment nginx-deployment
   

   輸出類似下面資訊:

    [email protected]:~/website$ kubectl describe deployment nginx-deployment
    Name:     nginx-deployment
    Namespace:    default
    CreationTimestamp:  Tue, 30 Aug 2016 18:11:37 -0700
    Labels:     app=nginx
    Annotations:    deployment.kubernetes.io/revision=1
    Selector:   app=nginx
    Replicas:   2 desired | 2 updated | 2 total | 2 available | 0 unavailable
    StrategyType:   RollingUpdate
    MinReadySeconds:  0
    RollingUpdateStrategy:  1 max unavailable, 1 max surge
    Pod Template:
      Labels:       app=nginx
      Containers:
       nginx:
        Image:              nginx:1.7.9
        Port:               80/TCP
        Environment:        <none>
        Mounts:             <none>
      Volumes:              <none>
    Conditions:
      Type          Status  Reason
      ----          ------  ------
      Available     True    MinimumReplicasAvailable
      Progressing   True    NewReplicaSetAvailable
    OldReplicaSets:   <none>
    NewReplicaSet:    nginx-deployment-1771418926 (2/2 replicas created)
    No events.
   

3. 列出部署所建立的pods :

   kubectl get pods -l app=nginx
   

   輸出類似下面資訊:

    NAME                                READY     STATUS    RESTARTS   AGE
    nginx-deployment-1771418926-7o5ns   1/1       Running   0          16h
    nginx-deployment-1771418926-r18az   1/1       Running   0          16h
   

4. 顯示關於一個pod的資訊:

   kubectl describe pod <pod-name>
   

   <pod-name> 是一個pod的名稱.

更新部署

您可以通過使用一個新的YAML檔案來更新部署。這個YAML檔案指定應該更新部署以使用nginx 1.8。

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.8 # Update the version of nginx from 1.7.9 to 1.8
        ports:
        - containerPort: 80

1. 應用新的YAML檔案:

   kubectl apply -f https://k8s.io/docs/tasks/run-application/deployment-update.yaml
   

2. 觀察部署建立的新pod，並刪除舊的pods:

   kubectl get pods -l app=nginx
   

通過增加副本數來擴充套件應用程式

您可以通過應用一個新的YAML檔案來增加部署的數量。這個YAML檔案將副本replicas設定為4，該檔案指定部署應該有4個pods：

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 4 # Update the replicas from 2 to 4
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.8
        ports:
        - containerPort: 80

1. 應用新的YAML檔案:

   kubectl apply -f https://k8s.io/docs/tasks/run-application/deployment-scale.yaml
   

2. 校驗部署有4個pods:

   kubectl get pods -l app=nginx
   

   輸出類似下面資訊:

    NAME                               READY     STATUS    RESTARTS   AGE
    nginx-deployment-148880595-4zdqq   1/1       Running   0          25s
    nginx-deployment-148880595-6zgi1   1/1       Running   0          25s
    nginx-deployment-148880595-fxcez   1/1       Running   0          2m
    nginx-deployment-148880595-rwovn   1/1       Running   0          2m
   

刪除部署

按名稱刪除部署:

kubectl delete deployment nginx-deployment

副本控制器——老方法

建立副本應用程式的首選方法是使用部署（Deployment），而部署（Deployment）反過來又使用了ReplicaSet。在將部署和副本新增到Kubernetes之前，副本的應用程式是通過使用副本控制器 ReplicationController來配置的。

下一節