Deployment管理Pods和ReplicaSets，提供聲明式更新。和老的ReplicationController（命令式管理）對應，發展趨勢是取代老的，所以後面也不會起文章單獨討論ReplicationController了。
但由Deployment-controller管理的Pods和ReplicaSets最好自始至終都由Deployment-controller管理，最好不要手動去管理，以免發生衝突。
創建Deployment
如下一個Deployment的配置（nginx-deployment.yaml），創建一個ReplicaSet包含3個nginx Pods
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80- apiVersion這裏爲apps/v1，如果是1.9之前的版本爲extensions/v1beta1
- replicas:3 起3個replicated Pods
- selector指明哪個pod被管理，這裏我們指定了label（app:nginx）
- template: spec 指明瞭運行一個容器nginx（以nginx:1.7.9爲鏡像）
- 開放80端口給container，以使container之間能發送和接收流量
注意這裏定義name 或 label 時不要和其他的重複，k8s不會檢查這個，需要人工自己確認
要創建此部署，執行下面的命令（在這之前我們提前下好nginx相關的鏡像，docker pull nginx:1.7.9）
[root@master yaml]# kubectl create -f nginx-deployment.yaml --record
deployment "nginx-deployment" created- --record會記錄操作歷史，以便於後面回滾操作
查看deployments
[root@master yaml]# kubectl get deployments
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx-deployment 3 0 0 0 1s- NAME：在集羣中的部署名稱
- DESIRED：顯示配置裏定義的副本數量，這是應該達到的副本數量
- CURRENT：當前正在運行的副本數量
- UP-TO-DATE：更新到當前所需狀態的副本數量
- AVAILABLE：可供使用的副本數量
- AEG：顯示app存活的時間
通過下面語句可查追蹤部署情況
[root@master ~]# kubectl rollout status deployment/nginx-deployment
deployment "nginx-deployment" successfully rolled out
# 這是部署完成的狀態
# 未完成的會顯示當前部署哪一步了
[root@master ~]# kubectl rollout status deployment/nginx-deployment
Waiting for rollout to finish: 2 out of 3 new replicas have been updated...
deployment "nginx-deployment" successfully rolled out過一會我們再查看，就全
[root@master ~]# kubectl get deployments
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx-deployment 3 3 3 3 51s這裏注意如果定義了.spec.minReadySeconds，那麼必須經過定義的時間纔會達到AVAILABLE 狀態
通過下面的命令查看Deployment創建的ReplicaSet（rs）
[root@master ~]# kubectl get rs
NAME DESIRED CURRENT READY AGE
nginx-deployment-6c54bd5869 3 3 3 56m注意ReplicaSet的名稱格式爲[DEPLOYMENT-NAME]-[POD-TEMPLATE-HASH-VALUE]，後面的hash值是由Deployment自動創建的
查看Pods
[root@master ~]# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
nginx-deployment-6c54bd5869-9brqp 1/1 Running 0 58m app=nginx,pod-template-hash=2710681425
nginx-deployment-6c54bd5869-dkmgh 1/1 Running 0 58m app=nginx,pod-template-hash=2710681425
nginx-deployment-6c54bd5869-vzsht 1/1 Running 0 58m app=nginx,pod-template-hash=2710681425創建的ReplicaSet 會確保時刻有3個nginx Pods的副本在運行
更新Deployment
假設我們想把nginx從1.7.9更新到1.9.1，有以下3種方式
1. 直接set命令設置變更的部分
$ kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1
deployment "nginx-deployment" image updated以上命令會自動回滾更改Pods，即停止一定量的老的，新建新的，直到來的終止完，新的啓動完
通過describe即可查看所有的細節
[root@master yaml]# kubectl describe deployment/nginx-deployment
Name: nginx-deployment
Namespace: default
CreationTimestamp: Thu, 15 Mar 2018 02:51:06 -0400
Labels: app=nginx
Annotations: deployment.kubernetes.io/revision=2
kubernetes.io/change-cause=kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1
Selector: app=nginx
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=nginx
Containers:
nginx:
Image: nginx:1.9.1
Port: 80/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: nginx-deployment-5964dfd755 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 2m deployment-controller Scaled up replica set nginx-deployment-5964dfd755 to 1
Normal ScalingReplicaSet 2m deployment-controller Scaled down replica set nginx-deployment-6c54bd5869 to 2
Normal ScalingReplicaSet 2m deployment-controller Scaled up replica set nginx-deployment-5964dfd755 to 2
Normal ScalingReplicaSet 2m deployment-controller Scaled down replica set nginx-deployment-6c54bd5869 to 1
Normal ScalingReplicaSet 2m deployment-controller Scaled up replica set nginx-deployment-5964dfd755 to 3
Normal ScalingReplicaSet 2m deployment-controller Scaled down replica set nginx-deployment-6c54bd5869 to 0- 可見image已經變了
- 另外Events可查看滾動更新的過程
- 另外上面的說的停止和新建的比例在這裏體現RollingUpdateStrategy: 25% max unavailable, 25% max surge，25% max unavailable確保在更新時只有部分會關閉（這裏是pod數的25%會關閉）。25% max surge確保創建新的pod也在一定比例上（這裏默認也是25%）
2. 通過直接修改線上的配置也可直接修改
kubectl edit deployment/nginx-deployment會打開一個編輯器，修改指定的部分即可，這裏是.spec.template.spec.containers[0].image
3. 修改yaml文件，通過apply重新部署
[root@master yaml]# kubectl apply -f nginx-deployment.yaml
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
deployment "nginx-deployment" configured但這裏有個警告: 也就是apply方式更新的資源應該是由kubectl create 加--save-config參數創建的 或 由apply創建的 （apply當資源不存在時會創建）
這時我們查看rs，會顯示新起了一個rs並將副本擴到3個，舊的rs都縮減爲0
[root@master yaml]# kubectl get rs
NAME DESIRED CURRENT READY AGE
nginx-deployment-5964dfd755 3 3 3 21m
nginx-deployment-6c54bd5869 0 0 0 1h
回滾Deployment
有時需要回滾的操作，比如更新錯誤，手誤等一系列問題
比如上面的操作更新到1.9.1時，寫錯了，寫成1.91了
[root@master yaml]# kubectl set image deployment/nginx-deployment nginx=nginx:1.91
deployment "nginx-deployment" image updated追蹤狀態
[root@master yaml]# kubectl rollout status deployments nginx-deployment
Waiting for rollout to finish: 1 out of 3 new replicas have been updated...
可見卡住不動了， Ctrl+C終止，查看rs如下
[root@master yaml]# kubectl get rs
NAME DESIRED CURRENT READY AGE
nginx-deployment-5964dfd755 3 3 3 40m
nginx-deployment-5d5cfdbd5f 1 1 0 1m
nginx-deployment-6c54bd5869 0 0 0 2h新的rs只啓動了Pod但沒有處於READY狀態
查看Pods
[root@master yaml]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-deployment-5964dfd755-8z8b7 1/1 Running 0 27m
nginx-deployment-5964dfd755-bnznj 1/1 Running 0 27m
nginx-deployment-5964dfd755-pt54q 1/1 Running 0 27m
nginx-deployment-5d5cfdbd5f-srdcc 0/1 ImagePullBackOff 0 2m可發現ImagePullBackOff，實際就是鏡像不存在
要修復這個，我們就需要rollback到前一個ok的版本
查看操作歷史
[root@master yaml]# kubectl rollout history deployment/nginx-deployment
deployments "nginx-deployment"
REVISION CHANGE-CAUSE
1 kubectl create -f docs/user-guide/nginx-deployment.yaml --record
2 kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1
3 kubectl set image deployment/nginx-deployment nginx=nginx:1.91要查看每個版本的詳細情況，指定--revision
[root@master yaml]# kubectl rollout history deployment/nginx-deployment --revision=2
deployments "nginx-deployment" with revision #2
Pod Template:
Labels: app=nginx
pod-template-hash=2710681425
Annotations: kubernetes.io/change-cause=kubectl edit deployment/nginx-deployment
Containers:
nginx:
Image: nginx:1.9.1
Port: 80/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
接下來進行回滾的操作
不指定版本，默認回滾到上一個版本
[root@master yaml]# kubectl rollout undo deployment/nginx-deployment
deployment "nginx-deployment" rolled back指定版本，通過--to-revision指定
[root@master yaml]# kubectl rollout undo deployment/nginx-deployment --to-revision=2
deployment "nginx-deployment" rolled back查看
kubectl describe deployment/nginx-deployment
....略
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
30m 30m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-2035384211 to 3
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 1
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-2035384211 to 2
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 2
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-2035384211 to 0
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-3066724191 to 2
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-3066724191 to 1
29m 29m 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-1564180365 to 2
2m 2m 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-3066724191 to 0
2m 2m 1 {deployment-controller } Normal DeploymentRollback Rolled back deployment "nginx-deployment" to revision 2
29m 2m 2 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 3可看到有DeploymentRollback Reason的事件
擴展Deployment
可通過如下的命令進行擴展
[root@master yaml]# kubectl scale deployment nginx-deployment --replicas=5
deployment "nginx-deployment" scaled查看Pods
[root@master yaml]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-deployment-5964dfd755-8z8b7 1/1 Running 0 41m
nginx-deployment-5964dfd755-bhm2s 1/1 Running 0 1m
nginx-deployment-5964dfd755-bnznj 1/1 Running 0 41m
nginx-deployment-5964dfd755-cftfj 1/1 Running 0 6s
nginx-deployment-5964dfd755-pt54q 1/1 Running 0 41m可見已擴展到5個
使用autoscale還可設置自動水平擴展（hpa），可根據機器負載之類的信息自動擴展或縮減，這個後面細講
$ kubectl autoscale deployment nginx-deployment --min=10 --max=15 --cpu-percent=80
deployment "nginx-deployment" autoscaled
暫停和恢復Deployment
有時需要修改多個部分，而不是上面的只修改image，這樣的話每次改完都自動部署，顯然不好，通過pause即可暫停Deployment，更改完了，通過resume即可恢復部署
暫停
[root@master yaml]# kubectl rollout pause deployment/nginx-deployment
deployment "nginx-deployment" paused修改
[root@master yaml]# kubectl set image deploy/nginx-deployment nginx=nginx:1.7.9
deployment "nginx-deployment" image updated查看Pods
[root@master yaml]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-deployment-5964dfd755-8z8b7 1/1 Running 0 57m
nginx-deployment-5964dfd755-bhm2s 1/1 Running 0 17m
nginx-deployment-5964dfd755-bnznj 1/1 Running 0 57m
nginx-deployment-5964dfd755-cftfj 1/1 Running 0 16m
nginx-deployment-5964dfd755-pt54q 1/1 Running 0 57m注意後面的AGE還是之前的Pod，這裏就不會自動更新了
恢復
[root@master yaml]# kubectl rollout resume deploy/nginx-deployment
deployment "nginx-deployment" resumed這時再查看Pods
[root@master yaml]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-deployment-6c54bd5869-htjxz 1/1 Running 0 25s
nginx-deployment-6c54bd5869-lj288 1/1 Running 0 30s
nginx-deployment-6c54bd5869-nt8lt 1/1 Running 0 30s
nginx-deployment-6c54bd5869-svqz6 1/1 Running 0 29s
nginx-deployment-6c54bd5869-zq8tl 1/1 Running 0 25s可見已經更新部署了
內部Deployment部分大概就講完了，下面把nginx服務暴露到外面
刪除Deployment
[root@master yaml]# kubectl delete -f nginx-deployment.yaml
deployment "nginx-deployment" deleted部署service
服務的暴露需要Service，它是Pod的抽象代理（具體機制見這裏）。見nginx-service.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
type: NodePort
sessionAffinity: ClientIP
selector:
app: nginx
ports:
- port: 80
nodePort: 30080- kind：Service代表是一個服務
- type：NodePort k8s將會在每個Node上打開一個端口並且每個Node的端口都是一樣的，通過<NodeIP>:NodePort的方式Kubernetes集羣外部的程序可以訪問Service。
- selector：哪個服務需要暴露
- port：service暴露的端口
- TargetPort：pod的端口
- nodePort：對外暴露的端口，不設置會默認分配，範圍：30000－32767
- 轉發邏輯是：
<NodeIP>:<nodeport> => <ServiceVIP>:<port>=> <PodIP>:<targetport>
部署service服務：
[root@master yaml]# kubectl create -f nginx-service.yaml
service "nginx-service" created可看到啓動了一個svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
svc/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 1d
svc/nginx-service NodePort 10.101.86.235 <none> 80:30080/TCP 4m瀏覽器測試
over！