Deployment管理Pods和ReplicaSets，提供声明式更新。和老的ReplicationController（命令式管理）对应，发展趋势是取代老的，所以后面也不会起文章单独讨论ReplicationController了。

但由Deployment-controller管理的Pods和ReplicaSets最好自始至终都由Deployment-controller管理，最好不要手动去管理，以免发生冲突。

创建Deployment

如下一个Deployment的配置（nginx-deployment.yaml），创建一个ReplicaSet包含3个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这里为apps/v1，如果是1.9之前的版本为extensions/v1beta1
• replicas:3 起3个replicated Pods
• selector指明哪个pod被管理，这里我们指定了label（app:nginx）
• template: spec 指明了运行一个容器nginx（以nginx:1.7.9为镜像）
• 开放80端口给container，以使container之间能发送和接收流量

注意这里定义name 或 label 时不要和其他的重复，k8s不会检查这个，需要人工自己确认

要创建此部署，执行下面的命令（在这之前我们提前下好nginx相关的镜像，docker pull nginx:1.7.9）

[root@master yaml]# kubectl create -f nginx-deployment.yaml --record deployment "nginx-deployment" created

• --record会记录操作历史，以便于后面回滚操作

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：在集群中的部署名称
• DESIRED：显示配置里定义的副本数量，这是应该达到的副本数量
• CURRENT：当前正在运行的副本数量
• UP-TO-DATE：更新到当前所需状态的副本数量
• AVAILABLE：可供使用的副本数量
• AEG：显示app存活的时间

通过下面语句可查追踪部署情况

[root@master ~]# kubectl rollout status deployment/nginx-deployment deployment "nginx-deployment" successfully rolled out # 这是部署完成的状态  # 未完成的会显示当前部署哪一步了 [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

过一会我们再查看，就全

[root@master ~]# kubectl get deployments NAME               DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE nginx-deployment   3         3         3            3           51s

这里注意如果定义了.spec.minReadySeconds，那么必须经过定义的时间才会达到AVAILABLE 状态

通过下面的命令查看Deployment创建的ReplicaSet（rs）

[root@master ~]# kubectl get rs NAME                          DESIRED   CURRENT   READY     AGE nginx-deployment-6c54bd5869   3         3         3         56m

注意ReplicaSet的名称格式为[DEPLOYMENT-NAME]-[POD-TEMPLATE-HASH-VALUE]，后面的hash值是由Deployment自动创建的

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

创建的ReplicaSet 会确保时刻有3个nginx Pods的副本在运行

更新Deployment

假设我们想把nginx从1.7.9更新到1.9.1，有以下3种方式

1. 直接set命令设置变更的部分

$ kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1 deployment "nginx-deployment" image updated

以上命令会自动回滚更改Pods，即停止一定量的老的，新建新的，直到来的终止完，新的启动完

通过describe即可查看所有的细节

[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

• 可见image已经变了
• 另外Events可查看滚动更新的过程
• 另外上面的说的停止和新建的比例在这里体现RollingUpdateStrategy:  25% max unavailable, 25% max surge，25% max unavailable确保在更新时只有部分会关闭（这里是pod数的25%会关闭）。25% max surge确保创建新的pod也在一定比例上（这里默认也是25%）

2. 通过直接修改线上的配置也可直接修改

kubectl edit deployment/nginx-deployment

会打开一个编辑器，修改指定的部分即可，这里是.spec.template.spec.containers[0].image

3. 修改yaml文件，通过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

但这里有个警告: 也就是apply方式更新的资源应该是由kubectl create 加--save-config参数创建的 或 由apply创建的 （apply当资源不存在时会创建）

这时我们查看rs，会显示新起了一个rs并将副本扩到3个，旧的rs都缩减为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

回滚Deployment

有时需要回滚的操作，比如更新错误，手误等一系列问题

比如上面的操作更新到1.9.1时，写错了，写成1.91了

[root@master yaml]# kubectl set image deployment/nginx-deployment nginx=nginx:1.91 deployment "nginx-deployment" image updated

追踪状态

[root@master yaml]# kubectl rollout status deployments nginx-deployment Waiting for rollout to finish: 1 out of 3 new replicas have been updated...  

可见卡住不动了， Ctrl+C终止，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只启动了Pod但没有处于READY状态

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

可发现ImagePullBackOff，实际就是镜像不存在

要修复这个，我们就需要rollback到前一个ok的版本

查看操作历史

[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

要查看每个版本的详细情况，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> 

接下来进行回滚的操作

不指定版本，默认回滚到上一个版本

[root@master yaml]# kubectl rollout undo deployment/nginx-deployment deployment "nginx-deployment" rolled back

指定版本，通过--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

扩展Deployment

可通过如下的命令进行扩展

[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

可见已扩展到5个

使用autoscale还可设置自动水平扩展（hpa），可根据机器负载之类的信息自动扩展或缩减，这个后面细讲

$ kubectl autoscale deployment nginx-deployment --min=10 --max=15 --cpu-percent=80 deployment "nginx-deployment" autoscaled

暂停和恢复Deployment

有时需要修改多个部分，而不是上面的只修改image，这样的话每次改完都自动部署，显然不好，通过pause即可暂停Deployment，更改完了，通过resume即可恢复部署

暂停

[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

注意后面的AGE还是之前的Pod，这里就不会自动更新了

恢复

[root@master yaml]# kubectl rollout resume deploy/nginx-deployment deployment "nginx-deployment" resumed

这时再查看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

可见已经更新部署了

内部Deployment部分大概就讲完了，下面把nginx服务暴露到外面

删除Deployment

[root@master yaml]# kubectl delete -f nginx-deployment.yaml  deployment "nginx-deployment" deleted

部署service

服务的暴露需要Service，它是Pod的抽象代理（具体机制见这里）。见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代表是一个服务
• type：NodePort k8s将会在每个Node上打开一个端口并且每个Node的端口都是一样的，通过<NodeIP>:NodePort的方式Kubernetes集群外部的程序可以访问Service。
• selector：哪个服务需要暴露
• port：service暴露的端口
• TargetPort：pod的端口
• nodePort：对外暴露的端口，不设置会默认分配，范围：30000－32767
• 转发逻辑是：
  <NodeIP>:<nodeport> => <ServiceVIP>:<port>=> <PodIP>:<targetport>

部署service服务：

[root@master yaml]# kubectl create -f nginx-service.yaml  service "nginx-service" created

可看到启动了一个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

浏览器测试

over！