Deployment介紹
為了更好地解決服務編排的問題，k8s在V1.2版本開始，引入了deployment控制器，值得一提的是，這種控制器並不直接管理pod，
而是通過管理replicaset來間接管理pod，即：deployment管理replicaset，replicaset管理pod。所以deployment比replicaset的功能更強大。
deployment的主要功能有下面幾個：
- 支援replicaset的所有功能
- 支援釋出的停止、繼續
- 支援版本的滾動更新和版本回退
deployment的資源清單檔案
apiVersion: apps/v1 #版本號 kind: Deployment #型別 metadata: #後設資料 name: #rs名稱 namespace: #所屬名稱空間 labels: #標籤 controller: deploy spec: #詳情描述 replicas: #副本數量 revisionHistoryLimit: #保留歷史版本，預設是10 paused: #暫停部署，預設是false progressDeadlineSeconds: #部署超時時間(s)，預設是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，可以為百分比，也可以為整數 maxUnavaliable: #最大不可用狀態的pod的最大值，可以為百分比，也可以為整數 selector: #選擇器，通過它指定該控制器管理哪些pod matchLabels: #Labels匹配規則 app: nginx-pod matchExpressions: #Expression匹配規則 - {key: app, operator: In, values: [nginx-pod]} template: #模板，當副本數量不足時，會根據下面的模板建立pod副本 metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1 ports: - containerPort: 80
建立deployment
建立pc-deployment.yaml，內容如下：
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
使用配置檔案
[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
檢視deployment控制的rs和pod，發現rs是在deployment之後加了一段字串，而pod是在rs之後加了一段字串
[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：命令列
格式
kubectl scale deploy deploy名稱 --replicas=pod數量 -n 名稱空間
通過命令列變更pod數量為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檔案
格式
kubectl edit deploy deploy名字 -n 名稱空間
通過編輯deploy檔案編輯pod數量為3個
[root@master ~]# kubectl edit deploy pc-deployment -n dev 找到replicas，將其數量改為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
映象更新
deployment支援兩種映象更新策略：重建更新和滾動更新（預設），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，支援兩個屬性： type：指定策略型別，支援兩種策略 Recreate：在建立出新的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，就啟動一部分，在更新過程中，存在兩個版本pod rollingUpdate：當type為RollingUpdate時生效，用於為RollingUpdate設定引數，支援兩個屬性 maxUnavailable：用來指定在升級過程中不可用pod的最大數量，預設為25% maxSurge：用來指定在升級過程中可以超過期望的pod的最大數量，預設為25%
重建更新
編輯pc-deployment.yaml，在spec節點下新增更新策略
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
建立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映象 [root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev deployment.apps/pc-deployment image updated
#再次檢視映象 [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
發現pod映象已經改變了
滾動更新
編輯pc-deployment.yaml，在spec節點下新增滾動更新策略（也可以把strategy去掉，因為預設滾動更新策略）
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
建立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 #更新映象 [root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev deployment.apps/pc-deployment image updated #檢視pod狀態 [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
發現pod是舊的一遍停止新的一邊建立，最後全變成了新的
滾動更新的過程
映象更新中rs的變化
前期準備：
#重建deployment [root@master ~]# kubectl delete -f pc-deployment.yaml deployment.apps "pc-deployment" deleted #新增record引數，表明建立時記錄 [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視窗，用於監聽rs和pod
在2視窗中監聽rs，3視窗中監聽pod
#在2視窗中輸入 [root@master ~]# kubectl get rs -n dev -w NAME DESIRED CURRENT READY AGE pc-deployment-5d89bdfbf9 3 3 3 6m18s #在3視窗中輸入 [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視窗中改變pod映象
[root@master ~]# kubectl set image deploy pc-deployment nginx=nginx:1.17.2 -n dev deployment.apps/pc-deployment image updated
檢視3視窗中pod的變化，發現序號5開頭的pod在逐漸暫停，序號6開頭的pod在逐漸建立
檢視2視窗中rs的變化，可以看見序號5開頭的rs的pod數在減少，序號6開頭的rs的pod數在增加
在1視窗中檢視最終rs變化，發現原來的rs依舊存在，只是pod數量變為了0，而後又新產生了一個rs，pod數量為3，其實這就是deployment能夠進行版本回退的奧妙所在，後面會詳細解釋
[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支援版本升級過程中的暫停，繼續功能以及版本回退等諸多功能，下面具體來看
kubectl rollout：版本升級相關功能，支援下面的選項：
- status：顯示當前升級狀態
- history：顯示升級歷史記錄
- pause：暫停版本升級過程
- resume：繼續已經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）
#檢視升級狀態 [root@master ~]# kubectl rollout status deploy pc-deployment -n dev deployment "pc-deployment" successfully rolled out #檢視升級歷史（注意：如果只顯示版本號說明一開始使用yaml建立檔案的時候沒有加上--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 #這裡使用--to-revision=1回滾到1版本，如果省略這個選項，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 #檢視是否回滾成功，發現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
金絲雀釋出
deployment支援更新過程中的控制，如"暫停（pause）"或"繼續（resume）"更新操作
比如有一批新的pod資源建立完成後立即暫停更新過程，此時，僅存在一部分新版本的應用，主體部分還是舊的版本。然後，再篩選一小部分的使用者請求路由到新的pod應用，繼續觀察能否穩定地按期望的方式執行。確定沒問題之後再繼續完成餘下的pod資源滾動更新，否則立即回滾更新操作。這就是所謂的金絲雀釋出。
#更新deployment版本，並配置暫停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 #檢視rs，發現老版本rs沒有減少，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 #在視窗2中檢視deploy狀態，發現deploy正在等待更新且已經有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... #在視窗1中繼續deploy的更新 [root@master ~]# kubectl rollout resume deploy pc-deployment -n dev deployment.apps/pc-deployment resumed #檢視視窗2的狀態 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 #在視窗1檢視rs更新結果，發現老版本均停止，新版本已經建立好 [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