Deployment介紹

為了更好地解決服務編排的問題甸陌，k8s在V1.2版本開始湘捎，引入了deployment控制器钟沛，值得一提的是，這種控制器并不直接管理pod伏穆，

而是通過管理replicaset來間接管理pod拘泞，即：deployment管理replicaset，replicaset管理pod枕扫。所以deployment比replicaset的功能更強大陪腌。

deployment的主要功能有下面幾個：

• 支持replicaset的所有功能
• 支持發(fā)布的停止、繼續(xù)
• 支持版本的滾動更新和版本回退

deployment的資源清單文件

apiVersion: apps/v1  #版本號
kind: Deployment  #類型
metadata:    #元數(shù)據(jù)
  name:    #rs名稱
  namespace:   #所屬命名空間
  labels:   #標簽
    controller: deploy
spec:   #詳情描述
  replicas:  #副本數(shù)量
  revisionHistoryLimit: #保留歷史版本烟瞧，默認是10
  paused: #暫停部署诗鸭，默認是false
  progressDeadlineSeconds: #部署超時時間(s)，默認是600
  strategy: #策略
    type: RollingUpdates  #滾動更新策略
    rollingUpdate:  #滾動更新
      maxSurge: #最大額外可以存在的副本數(shù)燕刻，可以為百分比只泼，也可以為整數(shù)
      maxUnavaliable: #最大不可用狀態(tài)的pod的最大值剖笙，可以為百分比卵洗，也可以為整數(shù)
  selector:  #選擇器，通過它指定該控制器管理哪些pod
    matchLabels:   #Labels匹配規(guī)則
       app: nginx-pod
    matchExpressions:   #Expression匹配規(guī)則
      - {key: app, operator: In, values: [nginx-pod]}
  template:  #模板弥咪，當副本數(shù)量不足時过蹂，會根據(jù)下面的模板創(chuàng)建pod副本
    metadata:
        labels:
          app: nginx-pod
    spec:
      containers:
      - name: nginx
        image: nginx:1.17.1
        ports:
        - containerPort: 80

創(chuàng)建deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pc-deployment
  namespace: dev
spec:
  replicas: 3
  selector:
    matchLabels:
     app: nginx-pod
  template:
    metadata:
      labels:
        app: nginx-pod
    spec:
      containers:
      - name: nginx
        image: nginx:1.17.1

使用配置文件

[root@master ~]# kubectl create -f pc-deployment.yaml 
deployment.apps/pc-deployment created
[root@master ~]# kubectl get deploy -n dev -o wide
NAME            READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES         SELECTOR
pc-deployment   3/3     3            3           16s   nginx        nginx:1.17.1   app=nginx-pod

查看deployment控制的rs和pod，發(fā)現(xiàn)rs是在deployment之后加了一段字符串聚至，而pod是在rs之后加了一段字符串

[root@master ~]# kubectl get rs -n dev
NAME                       DESIRED   CURRENT   READY   AGE
pc-deployment-5d89bdfbf9   3         3         3       2m13s
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-5d89bdfbf9-k8j9n   1/1     Running   0          2m42s
pc-deployment-5d89bdfbf9-vw87k   1/1     Running   0          2m42s
pc-deployment-5d89bdfbf9-x7nsm   1/1     Running   0          2m42s

deployment功能

擴縮容

方式一：命令行

kubectl scale deploy deploy名稱 --replicas=pod數(shù)量 -n 命名空間

通過命令行變更pod數(shù)量為5個

[root@master ~]# kubectl scale deploy pc-deployment --replicas=5 -n dev
deployment.apps/pc-deployment scaled
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-5d89bdfbf9-bhcns   1/1     Running   0          83s
pc-deployment-5d89bdfbf9-cfls7   1/1     Running   0          83s
pc-deployment-5d89bdfbf9-k8j9n   1/1     Running   0          8m54s
pc-deployment-5d89bdfbf9-vw87k   1/1     Running   0          8m54s
pc-deployment-5d89bdfbf9-x7nsm   1/1     Running   0          8m54s

方式二：編輯deploy文件

kubectl edit deploy deploy名字 -n 命名空間
通過編輯deploy文件編輯pod數(shù)量為3個

[root@master ~]# kubectl edit deploy pc-deployment -n dev
找到replicas酷勺，將其數(shù)量改為3
spec:
  progressDeadlineSeconds: 600
  replicas: 3
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-5d89bdfbf9-k8j9n   1/1     Running   0          15m
pc-deployment-5d89bdfbf9-vw87k   1/1     Running   0          15m
pc-deployment-5d89bdfbf9-x7nsm   1/1     Running   0          15m

鏡像更新

deployment支持兩種鏡像更新策略：重建更新和滾動更新（默認），可以通過strategy選項進行配置

strategy：指定新的pod替換舊的pod的策略扳躬，支持兩個屬性：
  type：指定策略類型脆诉，支持兩種策略
    Recreate：在創(chuàng)建出新的pod之前會先殺掉所有已存在的pod
    RollingUpdate：滾動更新，就是殺死一部分贷币，就啟動一部分击胜，在更新過程中，存在兩個版本pod
  rollingUpdate：當type為RollingUpdate時生效役纹，用于為RollingUpdate設置參數(shù)偶摔，支持兩個屬性
    maxUnavailable：用來指定在升級過程中不可用pod的最大數(shù)量，默認為25%
    maxSurge：用來指定在升級過程中可以超過期望的pod的最大數(shù)量促脉，默認為25%

重建更新

編輯pc-deployment.yaml辰斋，在spec節(jié)點下添加更新策略

spec:
  strategy:  #策略
    type: Recreate  #重建更新策略

[root@master ~]# vim pc-deployment.yaml 
[root@master ~]# kubectl apply -f pc-deployment.yaml 
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
deployment.apps/pc-deployment configured

創(chuàng)建deploy進行驗證

#首先記錄原本的pod名
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-5d89bdfbf9-bqf86   1/1     Running   0          8s
pc-deployment-5d89bdfbf9-kz6jt   1/1     Running   0          8s
pc-deployment-5d89bdfbf9-z7d9z   1/1     Running   0          8s
#更改pod鏡像
[root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev
deployment.apps/pc-deployment image updated
#再次查看鏡像
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-675d469f8b-b9rwd   1/1     Running   0          27s
pc-deployment-675d469f8b-kc7rr   1/1     Running   0          27s
pc-deployment-675d469f8b-kxgkq   1/1     Running   0          27s

發(fā)現(xiàn)pod鏡像已經(jīng)改變了

滾動更新

編輯pc-deployment.yaml策州，在spec節(jié)點下添加滾動更新策略（也可以把strategy去掉，因為默認滾動更新策略）

strategy:
  type: RollingUpdate #滾動更新策略
  rollingUpdate:
    maxUnavailable: 25%
    maxSurge: 25%

[root@master ~]# vim pc-deployment.yaml 
[root@master ~]# kubectl apply -f pc-deployment.yaml 
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
deployment.apps/pc-deployment configured

創(chuàng)建deploy進行驗證

#記錄以前的pod
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-5d89bdfbf9-526wf   1/1     Running   0          61s
pc-deployment-5d89bdfbf9-b5x5v   1/1     Running   0          64s
pc-deployment-5d89bdfbf9-kc7hb   1/1     Running   0          59s
#更新鏡像
[root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev
deployment.apps/pc-deployment image updated
#查看pod狀態(tài)
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS              RESTARTS   AGE
pc-deployment-5d89bdfbf9-526wf   0/1     Terminating         0          2m2s
pc-deployment-5d89bdfbf9-b5x5v   1/1     Running             0          2m5s
pc-deployment-5d89bdfbf9-kc7hb   0/1     Terminating         0          2m
pc-deployment-675d469f8b-7vw6x   1/1     Running             0          3s
pc-deployment-675d469f8b-rzq82   0/1     ContainerCreating   0          2s
pc-deployment-675d469f8b-zk4fs   1/1     Running             0          5s
[root@master ~]# kubectl get pod -n dev
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-675d469f8b-7vw6x   1/1     Running   0          38s
pc-deployment-675d469f8b-rzq82   1/1     Running   0          37s
pc-deployment-675d469f8b-zk4fs   1/1     Running   0          40s

發(fā)現(xiàn)pod是舊的一遍停止新的一邊創(chuàng)建宫仗，最后全變成了新的

滾動更新的過程

滾動更新

鏡像更新中rs的變化

前期準備：

#重建deployment
[root@master ~]# kubectl delete -f pc-deployment.yaml 
deployment.apps "pc-deployment" deleted
#添加record參數(shù)够挂，表明創(chuàng)建時記錄
[root@master ~]# kubectl create -f pc-deployment.yaml --record
deployment.apps/pc-deployment created
[root@master ~]# kubectl get deploy,rs,pod -n dev
NAME                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/pc-deployment   3/3     3            3           81s

NAME                                       DESIRED   CURRENT   READY   AGE
replicaset.apps/pc-deployment-5d89bdfbf9   3         3         3       81s

NAME                                 READY   STATUS    RESTARTS   AGE
pod/pc-deployment-5d89bdfbf9-4bg2j   1/1     Running   0          81s
pod/pc-deployment-5d89bdfbf9-gbt95   1/1     Running   0          81s
pod/pc-deployment-5d89bdfbf9-tstlh   1/1     Running   0          81s

新建兩個xshell窗口，用于監(jiān)聽rs和pod藕夫，在2窗口中監(jiān)聽rs下硕，3窗口中監(jiān)聽pod

#在2窗口中輸入
[root@master ~]# kubectl get rs -n dev -w
NAME                       DESIRED   CURRENT   READY   AGE
pc-deployment-5d89bdfbf9   3         3         3       6m18s
#在3窗口中輸入
[root@master ~]# kubectl get pod -n dev -w
NAME                             READY   STATUS    RESTARTS   AGE
pc-deployment-5d89bdfbf9-4bg2j   1/1     Running   0          6m56s
pc-deployment-5d89bdfbf9-gbt95   1/1     Running   0          6m56s
pc-deployment-5d89bdfbf9-tstlh   1/1     Running   0          6m56s

在1窗口中改變pod鏡像

[root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev
deployment.apps/pc-deployment image updated

查看3窗口中pod的變化，發(fā)現(xiàn)序號5開頭的pod在逐漸暫停汁胆，序號6開頭的pod在逐漸創(chuàng)建

查看2窗口中rs的變化梭姓，可以看見序號5開頭的rs的pod數(shù)在減少嫩码，序號6開頭的rs的pod數(shù)在增加

[root@master ~]# kubectl get rs -n dev
NAME                       DESIRED   CURRENT   READY   AGE
pc-deployment-5d89bdfbf9   0         0         0       11m
pc-deployment-675d469f8b   3         3         3       3m12s

版本回退

deployment支持版本升級過程中的暫停，繼續(xù)功能以及版本回退等諸多功能橡卤，下面具體來看

kubectl rollout：版本升級相關功能柜与，支持下面的選項：

• status：顯示當前升級狀態(tài)
• history：顯示升級歷史記錄
• pause：暫停版本升級過程
• resume：繼續(xù)已經(jīng)暫停的版本升級過程
• restart：重啟版本升級過程
• undo：回滾到上一級版本（可以使用--to-revision回滾到指定版本）

#查看升級狀態(tài)
[root@master ~]# kubectl rollout status deploy pc-deployment -n dev
deployment "pc-deployment" successfully rolled out

#查看升級歷史（注意：如果只顯示版本號說明一開始使用yaml創(chuàng)建文件的時候沒有加上--record命令）
[root@master ~]# kubectl rollout history deploy pc-deployment -n dev
deployment.apps/pc-deployment 
REVISION  CHANGE-CAUSE
1         kubectl create --filename=pc-deployment.yaml --record=true
2         kubectl create --filename=pc-deployment.yaml --record=true

#版本回滾
#這里使用--to-revision=1回滾到1版本，如果省略這個選項驹溃，則會回退到上個版本
[root@master ~]# kubectl rollout undo deploy pc-deployment --to-revision=1 -n dev
deployment.apps/pc-deployment rolled back

#查看是否回滾成功蚊惯，發(fā)現(xiàn)5序號開頭的rs被啟動了
[root@master ~]# kubectl get rs -n dev
NAME                       DESIRED   CURRENT   READY   AGE
pc-deployment-5d89bdfbf9   3         3         3       31m
pc-deployment-675d469f8b   0         0         0       22m

金絲雀發(fā)布

deployment支持更新過程中的控制俱诸，如"暫停（pause）"或"繼續(xù)（resume）"更新操作

比如有一批新的pod資源創(chuàng)建完成后立即暫停更新過程寓调，此時，僅存在一部分新版本的應用余黎，主體部分還是舊的版本重窟。然后，再篩選一小部分的用戶請求路由到新的pod應用惧财，繼續(xù)觀察能否穩(wěn)定地按期望的方式運行巡扇。確定沒問題之后再繼續(xù)完成余下的pod資源滾動更新，否則立即回滾更新操作垮衷。這就是所謂的金絲雀發(fā)布厅翔。

#更新deployment版本，并配置暫停deployment
[root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev && kubectl rollout pause deploy pc-deployment -n dev
deployment.apps/pc-deployment image updated
deployment.apps/pc-deployment paused

#查看rs搀突，發(fā)現(xiàn)老版本rs沒有減少知给，新版本rs增加一個
[root@master ~]# kubectl get rs -n dev
NAME                       DESIRED   CURRENT   READY   AGE
pc-deployment-5d89bdfbf9   3         3         3       44m
pc-deployment-675d469f8b   1         1         1       35m

#在窗口2中查看deploy狀態(tài)，發(fā)現(xiàn)deploy正在等待更新且已經(jīng)有1個更新好了
[root@master ~]# kubectl rollout status deploy pc-deployment -n dev
Waiting for deployment "pc-deployment" rollout to finish: 1 out of 3 new replicas have been updated...


#在窗口1中繼續(xù)deploy的更新
[root@master ~]# kubectl rollout resume deploy pc-deployment -n dev
deployment.apps/pc-deployment resumed

#查看窗口2的狀態(tài)
Waiting for deployment spec update to be observed...
Waiting for deployment spec update to be observed...
Waiting for deployment "pc-deployment" rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for deployment "pc-deployment" rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for deployment "pc-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "pc-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "pc-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "pc-deployment" rollout to finish: 1 old replicas are pending termination...
Waiting for deployment "pc-deployment" rollout to finish: 1 old replicas are pending termination...
deployment "pc-deployment" successfully rolled out

#在窗口1查看rs更新結(jié)果描姚，發(fā)現(xiàn)老版本均停止涩赢，新版本已經(jīng)創(chuàng)建好
[root@master ~]# kubectl get rs -n dev
NAME                       DESIRED   CURRENT   READY   AGE
pc-deployment-5d89bdfbf9   0         0         0       49m
pc-deployment-675d469f8b   3         3         3       40m

原文地址