在 kubernetes中，Pod 是最小的控制单元，但是 kubernetes 很少直接控制 Pod，一般都是通过 Pod 控制器来完成的。Pod 控制器用于 pod 的管理，确保 pod 资源符合预期的状态，当 pod 的资源出现故障时，会尝试进行重启或重建 pod。所以有的时候删除 pod，发现还会存在就是因为 pod 控制器的存在。在 kubernetes 中 Pod 控制器的种类有很多，Deployment 就是其中的一种。
    命令操作

    1. # 命令格式: kubectl run deployment名称  [参数] 
    2. # --image  指定pod的镜像
    3. # --port   指定端口
    4. # --replicas  指定创建pod数量，不指定默认就是一个
    5. # --namespace  指定namespace
    6. [root@master ~]# kubectl run nginx --image=nginx:1.17.1 --port=80 --replicas=3 -n dev
    7. deployment.apps/nginx created
    9. # 查看创建的Pod
    10. [root@master ~]# kubectl get pods -n dev
    11. NAME                     READY   STATUS    RESTARTS   AGE
    12. nginx-5ff7956ff6-6k8cb   1/1     Running   0          19s
    13. nginx-5ff7956ff6-jxfjt   1/1     Running   0          19s
    14. nginx-5ff7956ff6-v6jqw   1/1     Running   0          19s
    16. # 查看deployment的信息
    17. [root@master ~]# kubectl get deploy -n dev
    18. NAME    READY   UP-TO-DATE   AVAILABLE   AGE
    19. nginx   3/3     3            3           2m42s
    21. # UP-TO-DATE：成功升级的副本数量
    22. # AVAILABLE：可用副本的数量
    23. [root@master ~]# kubectl get deploy -n dev -o wide
    24. NAME    READY UP-TO-DATE  AVAILABLE   AGE     CONTAINERS   IMAGES              SELECTOR
    25. nginx   3/3     3         3           2m51s   nginx        nginx:1.17.1        run=nginx
    27. # 查看deployment的详细信息
    28. [root@master ~]# kubectl describe deploy nginx -n dev
    29. Name:                   nginx
    30. Namespace:              dev
    31. CreationTimestamp:      Wed, 08 Apr 2020 11:14:14 +0800
    32. Labels:                 run=nginx
    33. Annotations:            deployment.kubernetes.io/revision: 1
    34. Selector:               run=nginx
    35. Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
    36. StrategyType:           RollingUpdate
    37. MinReadySeconds:        0
    38. RollingUpdateStrategy:  25% max unavailable, 25% max surge
    39. Pod Template:
    40.   Labels:  run=nginx
    41.   Containers:
    42.    nginx:
    43.     Image:        nginx:1.17.1
    44.     Port:         80/TCP
    45.     Host Port:    0/TCP
    46.     Environment:  <none>
    47.     Mounts:       <none>
    48.   Volumes:        <none>
    49. Conditions:
    50.   Type           Status  Reason
    51.   ----           ------  ------
    52.   Available      True    MinimumReplicasAvailable
    53.   Progressing    True    NewReplicaSetAvailable
    54. OldReplicaSets:  <none>
    55. NewReplicaSet:   nginx-5ff7956ff6 (3/3 replicas created)
    56. Events:
    57.   Type    Reason             Age    From                   Message
    58.   ----    ------             ----   ----                   -------
    59.   Normal  ScalingReplicaSet  5m43s  deployment-controller  Scaled up replicaset nginx-5ff7956ff6 to 3
    61. # 删除 
    62. [root@master ~]# kubectl delete deploy nginx -n dev
    63. deployment.apps "nginx" deleted

    image.png
    配置操作
    创建一个deploy-nginx.yaml，内容如下：

    1. apiVersion: apps/v1
    2. kind: Deployment
    3. metadata:
    4.   name: nginx
    5.   namespace: dev
    6. spec:
    7.   replicas: 3
    8.   selector:
    9.     matchLabels:
    10.       run: nginx
    11.   template:
    12.     metadata:
    13.       labels:
    14.         run: nginx
    15.     spec:
    16.       containers:
    17.       - image: nginx:1.17.1
    18.         name: nginx
    19.         ports:
    20.         - containerPort: 80
    21.           protocol: TCP

    然后就可以执行对应的创建和删除命令了：
    创建：kubectl create -f deploy-nginx.yaml
    删除：kubectl delete -f deploy-nginx.yaml