Deployment简述

Deployment 为 Pod 和 ReplicaSet 提供了一个声明式定义(declarative)方法，用来替代以前的ReplicationController 来方便的管理应用。典型的应用场景包括：
- 定义Deployment来创建Pod和ReplicaSet
- 滚动升级和回滚应用
- 扩容和缩容
- 暂停和继续Deployment

您只需要在 Deployment 中描述您想要的目标状态是什么，Deployment controller 就会帮您将 Pod 和ReplicaSet 的实际状态改变到您的目标状态。您可以定义一个全新的 Deployment 来创建 ReplicaSet 或者删除已有的 Deployment 并创建一个新的来替换。

Deployment用例:
- 使用Deployment来创建ReplicaSet。ReplicaSet在后台创建pod。
- 检查启动状态，看它是成功还是失败。
- 通过更新Deployment的PodTemplateSpec字段来声明Pod的新状态
- 创建一个新的ReplicaSet，Deployment会按照控制的速率将pod从旧的ReplicaSet移动到新的ReplicaSet中。
- 如果当前状态不稳定，回滚到之前的Deployment revision。每次回滚都会更新Deployment的revision。
- 扩容Deployment以满足更高的负载。
- 暂停Deployment来应用PodTemplateSpec的多个修复，然后恢复上线。
- 根据Deployment 的状态判断上线是否hang住了。
- 清除旧的不必要的 ReplicaSet。
  
  image.png

总结
- 用户通过 kubectl 创建 Deployment。
- Deployment 创建 ReplicaSet。
- ReplicaSet 创建 Pod。

对象的命名方式是：子对象的名字 = 父对象名字 + 随机字符串或数字。

image.jpg

Deployment资源清单

Deployment 也需要apiVersion，kind和metadata这些配置项

[root@k8s-master01 learning]# kubectl explain deployment
KIND:     Deployment
VERSION:  extensions/v1beta1

DESCRIPTION:
     DEPRECATED - This group version of Deployment is deprecated by
     apps/v1beta2/Deployment. See the release notes for more information.
     Deployment enables declarative updates for Pods and ReplicaSets.

FIELDS:
   apiVersion   <string>
     APIVersion defines the versioned schema of this representation of an
     object. Servers should convert recognized schemas to the latest internal
     value, and may reject unrecognized values. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#resources

   kind <string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds

   metadata     <Object>
     Standard object metadata.

   spec <Object>
     Specification of the desired behavior of the Deployment.

   status       <Object>
     Most recently observed status of the Deployment.

spec字段参数

Replicas: 可选字段，指定期望的pod数量，默认是1
Selector: 可选字段, 用来指定 label selector ，圈定Deployment管理的pod范围
- 如果被指定: 必须匹配 .spec.template.metadata.labels，否则它将被API拒绝
- 如果未指定: .spec.selector.matchLabels 默认是.spec.template.metadata.labels
- 在Pod的template跟.spec.template不同或者数量超过了.spec.replicas规定的数量的情况下，Deployment会杀掉label跟selector不同的Pod
Template: 必须字段, 划分Pod的范围，Deployment中的pod template必须指定适当的label
strategy: 可选字段, 指定新的Pod替换旧的Pod的策略,可以是"Recreate"或者是 "RollingUpdate"。默认值是"RollingUpdate"
- Recreate: 重建式更新，就是删一个建一个
- rollingUpdate：滚动更新，简单定义更新期间pod最多有几个等
  - maxSurge: 可选字段，用来指定可以超过期望的Pod数量的最大个数,默认是25%,之前是1
  - maxUnavailable: 可选字段，用来指定不可用Pod数量的最大个数,默认是25%,之前是1
revisionHistoryLimit: 可选字段，指定保留的旧的ReplicaSet数量,默认是10
rollbackTo: 可选字段，设置该参数将触发回退操作，每次回退完成后，该值就会被清除
- revision: 可选字段，用来指定回退到的revision。默认是0,意味着回退到上一个revision。
progressDeadlineSeconds: 可选字段，用来指定在系统报告Deployment的failed progressing——表现为resource的状态中type=Progressing、Status=False、 Reason=ProgressDeadlineExceeded前可以等待的Deployment进行的秒数
minReadySeconds: 可选字段，指定没有任何容器crash的Pod并被认为是可用状态的最小秒数。默认是0（Pod在ready后就会被认为是可用状态）
paused: 可选字段，用来指定暂停和恢复Deployment。Paused和没有paused的Deployment之间的唯一区别就是，所有对paused deployment中的PodTemplateSpec的修改都不会触发新的rollout。Deployment被创建之后默认是非paused。

定义资源清单

[root@k8s-master01 learning]# vim deployment-demo.yaml 
apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: deploy-demo
  namespace: learning
spec:
  replicas: 2
  selector:
    matchLabels:
      app: deploy-demo
      tag: learn-deploy
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: deploy-demo
        tag: learn-deploy
    spec:
      containers:
      - name: deploy-demo
        image: nginx:1.10
        imagePullPolicy: IfNotPresent
        ports: 
        - name: http
          containerPort: 80
        livenessProbe:
          failureThreshold: 3
          httpGet:
            path: /index.html
            port: 80
            scheme: HTTP
          initialDelaySeconds: 20
          periodSeconds: 2
          successThreshold: 1
          timeoutSeconds: 1
        readinessProbe:
          failureThreshold: 3
          httpGet:
            path: /index.html
            port: 80
            scheme: HTTP
          initialDelaySeconds: 20
          periodSeconds: 2
          successThreshold: 2
          timeoutSeconds: 1

常用命令

查看资源

[root@k8s-master01 learning]# kubectl apply -f deployment-demo.yaml 
deployment.apps/deploy-demo created

# 查看创建的deployments
[root@k8s-master01 learning]# kubectl get deployments. -n learning     
NAME          READY   UP-TO-DATE   AVAILABLE   AGE
deploy-demo   2/2     2            2           2m4s

# 查看deployment管理的replicaset
[root@k8s-master01 learning]# kubectl get replicasets. -n learning               
NAME                     DESIRED   CURRENT   READY   AGE
deploy-demo-5c64bd4959   2         2         2       2m11s

# 查看replicaset管理的pod
[root@k8s-master01 learning]# kubectl get pods -n learning              
NAME                           READY   STATUS    RESTARTS   AGE
deploy-demo-5c64bd4959-5ltxf   1/1     Running   0          2m18s
deploy-demo-5c64bd4959-b6pth   1/1     Running   0          2m18s

# 查看详细信息 
[root@k8s-master01 learning]# kubectl describe deployments. -n learning deploy-demo 
Name:                   deploy-demo
Namespace:              learning
CreationTimestamp:      Mon, 28 Jan 2019 20:01:31 +0800
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
                        kubectl.kubernetes.io/last-applied-configuration:
                          {"apiVersion":"apps/v1beta2","kind":"Deployment","metadata":{"annotations":{},"name":"deploy-demo","namespace":"learning"},"spec":{"replic...
Selector:               app=deploy-demo,tag=learn-deploy
Replicas:               2 desired | 2 updated | 2 total | 2 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  0 max unavailable, 1 max surge
Pod Template:
  Labels:  app=deploy-demo
           tag=learn-deploy
  Containers:
   deploy-demo:
    Image:        nginx:1.10
    Port:         80/TCP
    Host Port:    0/TCP
    Liveness:     http-get http://:80/index.html delay=20s timeout=1s period=2s #success=1 #failure=3
    Readiness:    http-get http://:80/index.html delay=20s timeout=1s period=2s #success=2 #failure=3
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   deploy-demo-5c64bd4959 (2/2 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  6m46s  deployment-controller  Scaled up replica set deploy-demo-5c64bd4959 to 2

修改Pod数量

1. 修改配置文件,然后apply -f
2. edit在线编辑
3. 打补丁的方式
[root@k8s-master01 learning]# kubectl patch deployments. -n learning  deploy-demo -p '{"spec":{"replicas":5}}'
deployment.extensions/deploy-demo patched

[root@k8s-master01 learning]# kubectl get pods -n learning 
NAME                           READY   STATUS    RESTARTS   AGE
deploy-demo-5c64bd4959-89spz   1/1     Running   0          3m33s
deploy-demo-5c64bd4959-hxg6b   1/1     Running   0          33s
deploy-demo-5c64bd4959-k7dnr   1/1     Running   0          3m9s
deploy-demo-5c64bd4959-pz2wb   1/1     Running   0          33s
deploy-demo-5c64bd4959-vl55c   1/1     Running   0          33s

升级版本

1. 修改配置文件,然后apply -f
2. edit在线编辑
3. sed image修改
[root@k8s-master01 ~]# kubectl set image deployment deploy-demo deploy-demo=nginx:1.13 -n learning   
deployment.extensions/deploy-demo image updated
[root@k8s-master01 ~]# kubectl get deployments. -n learning  -o wide
NAME          READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS    IMAGES       SELECTOR
deploy-demo   5/5     3            5           41m   deploy-demo   nginx:1.13   app=deploy-demo,tag=learn-deploy

# 升级版本 查看升级过程
# 修改配置文件升级,观察升级过程,可以看出是先增加一个,当新增加的状态为running后才进行删除一个,删除后在增加,直到升级完成
[root@k8s-master01 learning]# sed -i 's/        image: nginx:1.10/        image: nginx:1.11/g'  deployment-demo.yaml 
[root@k8s-master01 learning]# kubectl apply -f deployment-demo.yaml & kubectl get pods -n learning  -w -o wide -l app=deploy-demo
NAME                           READY   STATUS    RESTARTS   AGE 
deploy-demo-5c64bd4959-48frt   1/1     Running   0          45s
deploy-demo-5c64bd4959-rprrl   1/1     Running   0          45s
deployment.apps/deploy-demo configured

deploy-demo-5d56cdb4cd-llf4m   0/1   Pending   0     0s
deploy-demo-5d56cdb4cd-llf4m   0/1   Pending   0     0s
deploy-demo-5d56cdb4cd-llf4m   0/1   ContainerCreating   0     0s
deploy-demo-5d56cdb4cd-llf4m   0/1   Running   0     2s
deploy-demo-5d56cdb4cd-llf4m   1/1   Running   0     23s
deploy-demo-5c64bd4959-48frt   1/1   Terminating   0
deploy-demo-5d56cdb4cd-trtfz   0/1   Pending   0     0s
deploy-demo-5d56cdb4cd-trtfz   0/1   Pending   0     0s
deploy-demo-5d56cdb4cd-trtfz   0/1   ContainerCreating   0     0s
deploy-demo-5c64bd4959-48frt   0/1   Terminating   0     68s
deploy-demo-5d56cdb4cd-trtfz   0/1   Running   0     1s
deploy-demo-5c64bd4959-48frt   0/1   Terminating   0     69s
deploy-demo-5c64bd4959-48frt   0/1   Terminating   0     69s
deploy-demo-5c64bd4959-48frt   0/1   Terminating   0     73s
deploy-demo-5c64bd4959-48frt   0/1   Terminating   0     73s
deploy-demo-5d56cdb4cd-trtfz   1/1   Running   0     24s
deploy-demo-5c64bd4959-rprrl   1/1   Terminating   0     92s
deploy-demo-5c64bd4959-rprrl   0/1   Terminating   0     93s
deploy-demo-5c64bd4959-rprrl   0/1   Terminating   0     101s
deploy-demo-5c64bd4959-rprrl   0/1   Terminating   0     101s

# 查看升级后的rs
[root@k8s-master01 learning]# kubectl get rs -n learning  -o wide
NAME                     DESIRED   CURRENT   READY   AGE     CONTAINERS    IMAGES       SELECTOR
deploy-demo-5c64bd4959   0         0         0       5m7s    deploy-demo   nginx:1.10   app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy
deploy-demo-5d56cdb4cd   2         2         2       4m22s   deploy-demo   nginx:1.11   app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy

回滚到上个版本

只要 Deployment 的 rollout 被触发就会创建一个 revision。也就是说当且仅当 Deployment 的 Pod template（如.spec.template）被更改，例如更新template 中的 label 和容器镜像时，就会创建出一个新的 revision

# 查看最近的历史版本
[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo                                                                 
deployment.extensions/deploy-demo 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

# 查看历史版本信息
[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo --revision=2
deployment.extensions/deploy-demo with revision #2
Pod Template:
  Labels:       app=deploy-demo
        pod-template-hash=5d56cdb4cd
        tag=learn-deploy
  Containers:
   deploy-demo:
    Image:      nginx:1.11
    Port:       80/TCP
    Host Port:  0/TCP
    Liveness:   http-get http://:80/index.html delay=20s timeout=1s period=2s #success=1 #failure=3
    Readiness:  http-get http://:80/index.html delay=20s timeout=1s period=2s #success=2 #failure=3
    Environment:        <none>
    Mounts:     <none>
  Volumes:      <none>

# 回退历史版本，默认是回退到上一个版本
[root@k8s-master01 learning]# kubectl rollout undo deployment -n learning deploy-demo          
deployment.extensions/deploy-demo rolled back
# 第二个版本已经不存在了,已经成了最新的第四个版本
[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo 
deployment.extensions/deploy-demo 
REVISION  CHANGE-CAUSE
1         <none>
3         <none>
4         <none>
# 通过这里可以看到已经回退到了1.11版本
[root@k8s-master01 learning]# kubectl get rs -n learning -o wide 
NAME                     DESIRED   CURRENT   READY   AGE     CONTAINERS    IMAGES       SELECTOR
deploy-demo-57cdd6d965   0         0         0       2m19s   deploy-demo   nginx:1.12   app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy
deploy-demo-5c64bd4959   0         0         0       10m     deploy-demo   nginx:1.10   app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy
deploy-demo-5d56cdb4cd   2         2         2       9m44s   deploy-demo   nginx:1.11   app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy

回滚到指定版本

# 查看现存的版本
[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo                                                
deployment.extensions/deploy-demo 
REVISION  CHANGE-CAUSE
1         <none>
3         <none>
4         <none>

# 回滚到第一个版本
[root@k8s-master01 learning]# kubectl rollout undo deployment -n learning deploy-demo  --to-revision=1
deployment.extensions/deploy-demo rolled back
# 可以看到第一个版本已经变成了现在的第五个版本
[root@k8s-master01 learning]# kubectl rollout history deployment -n learning deploy-demo              
deployment.extensions/deploy-demo 
REVISION  CHANGE-CAUSE
3         <none>
4         <none>
5         <none>

[root@k8s-master01 learning]# kubectl get rs -n learning -o wide
NAME                     DESIRED   CURRENT   READY   AGE     CONTAINERS    IMAGES       SELECTOR
deploy-demo-57cdd6d965   0         0         0       5m31s   deploy-demo   nginx:1.12   app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy
deploy-demo-5c64bd4959   2         2         2       13m     deploy-demo   nginx:1.10   app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy
deploy-demo-5d56cdb4cd   0         0         0       12m     deploy-demo   nginx:1.11   app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy

暂停和恢复

你可以在出发一次或多次更新前暂停一个Deployment，然后再恢复它。这样你就能多次暂停和恢复Deployment，在此期间进行一些修复工作，而不会出发不必要的rollout

1. 更新nginx到1.13版本，并配置暂停deployment
[root@k8s-master01 learning]# kubectl set image deployment deploy-demo deploy-demo=nginx:1.13 -n learning && kubectl rollout pause deployment  deploy-demo -n learning 
deployment.extensions/deploy-demo image updated
deployment.extensions/deploy-demo paused

2. 监控更新的过程，因为pause命令,只是新增了一个资源，并没有去删除旧资源
[root@k8s-master01 learning]# kubectl get pods -n learning                    
NAME                           READY   STATUS    RESTARTS   AGE
deploy-demo-5c64bd4959-rm99c   1/1     Running   0          2m46s
deploy-demo-5c64bd4959-x7ctm   1/1     Running   0          2m23s
deploy-demo-6b876f975b-6kq4d   1/1     Running   0          83s  #新加的
# 在rs里面可以清楚的看到
[root@k8s-master01 learning]# kubectl get rs -l app=deploy-demo -n learning -o wide -n learning     
NAME                     DESIRED   CURRENT   READY   AGE   CONTAINERS    IMAGES       SELECTOR
deploy-demo-57cdd6d965   0         0         0       44m   deploy-demo   nginx:1.12   app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy
deploy-demo-5c64bd4959   2         2         2       52m   deploy-demo   nginx:1.10   app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy
deploy-demo-5d56cdb4cd   0         0         0       51m   deploy-demo   nginx:1.11   app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy
deploy-demo-6b876f975b   1         1         1       11m   deploy-demo   nginx:1.13   app=deploy-demo,pod-template-hash=6b876f975b,tag=learn-deploy

3. 确保更新的pod没问题了，继续更新
[root@k8s-master01 learning]# kubectl rollout resume deployment deploy-demo -n learning 
deployment.extensions/deploy-demo resumed

4. 更新后结果
[root@k8s-master01 learning]# kubectl get pods -n learning  
NAME                           READY   STATUS    RESTARTS   AGE
deploy-demo-6b876f975b-6kq4d   1/1     Running   0          4m17s
deploy-demo-6b876f975b-szw4s   1/1     Running   0          53s
# 可以看到 都已经到了1.13版本了
[root@k8s-master01 learning]# kubectl get rs -l app=deploy-demo -n learning -o wide -n learning 
NAME                     DESIRED   CURRENT   READY   AGE   CONTAINERS    IMAGES       SELECTOR
deploy-demo-57cdd6d965   0         0         0       46m   deploy-demo   nginx:1.12   app=deploy-demo,pod-template-hash=57cdd6d965,tag=learn-deploy
deploy-demo-5c64bd4959   0         0         0       54m   deploy-demo   nginx:1.10   app=deploy-demo,pod-template-hash=5c64bd4959,tag=learn-deploy
deploy-demo-5d56cdb4cd   0         0         0       53m   deploy-demo   nginx:1.11   app=deploy-demo,pod-template-hash=5d56cdb4cd,tag=learn-deploy
deploy-demo-6b876f975b   2         2         2       13m   deploy-demo   nginx:1.13   app=deploy-demo,pod-template-hash=6b876f975b,tag=learn-deploy

kubernetes Pod控制器 Deployment

Deployment简述

Deployment资源清单

spec字段参数

定义资源清单

常用命令

查看资源

修改Pod数量

升级版本

回滚到上个版本

回滚到指定版本

暂停和恢复

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