Kubernetes m6S之资源同步控制器RC、RS、Deployment精解

Z时代
2024-01-10
分类：技术分享

Kubernetes的资源控制器ReplicationController（RC）、ReplicaSet（RS）、Deployment（Deploy）详解与示例

主机配置规划

服务器名称(hostname)	系统版本	配置	内网IP	外网IP(模拟)
k8s-master	CentOS7.7	2C/4G/20G	172.16.1.110	10.0.0.110
k8s-node01	CentOS7.7	2C/4G/20G	172.16.1.111	10.0.0.111
k8s-node02	CentOS7.7	2C/4G/20G	172.16.1.112	10.0.0.112

什么是控制器

kubernetes中内建了很多controller（控制器），这些相当于一个状态机，用来控制pod的具体状态和行为。

部分控制器类型如下：

ReplicationController 和 ReplicaSet

Deployment

DaemonSet

StatefulSet

Job/CronJob

HorizontalPodAutoscaler

ReplicationController 和 ReplicaSet

ReplicationController (RC)用来确保容器应用的副本数始终保持在用户定义的副本数，即如果有容器异常退出，会自动创建新的pod来替代；而异常多出来的容器也会自动回收。

在新版的Kubernetes中建议使用ReplicaSet (RS)来取代ReplicationController。ReplicaSet跟ReplicationController没有本质的不同，只是名字不一样，但ReplicaSet支持集合式selector。

虽然 ReplicaSets 可以独立使用，但如今它主要被Deployments 用作协调 Pod 的创建、删除和更新的机制。当使用 Deployment 时，你不必担心还要管理它们创建的 ReplicaSet，Deployment 会拥有并管理它们的 ReplicaSet。

ReplicaSet 是下一代的 Replication Controller。 ReplicaSet 和 Replication Controller 的唯一区别是选择器的支持。ReplicaSet 支持新的基于集合的选择器需求，这在标签用户指南中有描述。而 Replication Controller 仅支持基于相等选择器的需求。

Deployments

Deployment 控制器为 Pods和 ReplicaSets提供描述性的更新方式。用来替代以前的ReplicationController以方便管理应用。

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

ReplicaSet示例

yaml文件

1 [root@k8s-master controller]# pwd

2 /root/k8s_practice/controller

3 [root@k8s-master controller]# cat ReplicaSet-01.yaml

4 apiVersion: apps/v1

5kind: ReplicaSet

6metadata:

7 name: frontend

8spec:

9 replicas: 3

10 selector:

11 matchLabels:

12 tier: frontend

13 template:

14 metadata:

15 labels:

16 tier: frontend

17 spec:

18 containers:

19 - name: nginx

20 image: registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17

21 imagePullPolicy: IfNotPresent

22 ports:

23 - name: httpd

24 containerPort: 80

创建ReplicaSet，并查看rs状态与详情

 1 [root@k8s-master controller]# kubectl apply -f ReplicaSet-01.yaml
 2 replicaset.apps/frontend created
 3 [root@k8s-master controller]# kubectl get rs -o wide    # 查看状态
 4NAME       DESIRED   CURRENT   READY   AGE     CONTAINERS   IMAGES                                                        SELECTOR
 5 frontend   333       2m12s   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17   tier=frontend
 6 [root@k8s-master controller]#
 7 [root@k8s-master controller]# kubectl describe rs frontend   # 查看详情
 8Name:         frontend
 9Namespace:    default
10 Selector:     tier=frontend
11 Labels:       <none>
12 Annotations:  kubectl.kubernetes.io/last-applied-configuration:
13                 {"apiVersion":"apps/v1","kind":"ReplicaSet","metadata":{"annotations":{},"name":"frontend","namespace":"default"},"spec":{"replicas":3,"se...
14 Replicas:     3 current / 3 desired
15 Pods Status:  3 Running / 0 Waiting / 0 Succeeded / 0 Failed
16Pod Template:
17   Labels:  tier=frontend
18  Containers:
19   nginx:
20     Image:        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17
21     Port:         80/TCP
22     Host Port:    0/TCP
23     Environment:  <none>
24     Mounts:       <none>
25   Volumes:        <none>
26Events:
27  Type    Reason            Age    From                   Message
28   ----    ------            ----   ----                   -------
29   Normal  SuccessfulCreate  10m    replicaset-controller  Created pod: frontend-kltwp
30   Normal  SuccessfulCreate  10m    replicaset-controller  Created pod: frontend-76dbn
31   Normal  SuccessfulCreate  10m    replicaset-controller  Created pod: frontend-jk8td

查看pod状态信息

1 [root@k8s-master controller]# kubectl get pod -o wide --show-labels
2NAME             READY   STATUS    RESTARTS   AGE     IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
3 frontend-76dbn   1/1     Running   0          5m15s   10.244.4.31   k8s-node01   <none>           <none>            tier=frontend
4 frontend-jk8td   1/1     Running   0          5m15s   10.244.2.35   k8s-node02   <none>           <none>            tier=frontend
5 frontend-kltwp   1/1     Running   0          5m15s   10.244.2.34   k8s-node02   <none>           <none>            tier=frontend

删除一个pod，然后再次查看

1 [root@k8s-master controller]# kubectl delete pod frontend-kltwp
2 pod "frontend-kltwp" deleted
3 [root@k8s-master controller]#
4 [root@k8s-master controller]# kubectl get pod -o wide --show-labels   # 可见重新创建了一个pod
5NAME             READY   STATUS    RESTARTS   AGE     IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
6 frontend-76dbn   1/1     Running   0          7m27s   10.244.4.31   k8s-node01   <none>           <none>            tier=frontend
7 frontend-jk8td   1/1     Running   0          7m27s   10.244.2.35   k8s-node02   <none>           <none>            tier=frontend
8 frontend-mf79k   1/1     Running   0          16s     10.244.4.32   k8s-node01   <none>           <none>            tier=frontend

由上可见，rs又新建了一个pod，保证了pod数总是为3.

Deployment示例

创建 Deployment

yaml文件

1 [root@k8s-master controller]# pwd

2 /root/k8s_practice/controller

3 [root@k8s-master controller]# cat nginx-deployment-1.17.1.yaml

4 apiVersion: apps/v1

5kind: Deployment

6metadata:

7 name: nginx-deployment

8 labels:

9 app: nginx

10spec:

11 replicas: 3

12 # 重点关注该字段

13 selector:

14 matchLabels:

15 app: nginx

16 template:

17 metadata:

18 labels:

19 app: nginx

20 spec:

21 containers:

22 - name: nginx

23 image: registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1

24 ports:

25 - containerPort: 80

26 [root@k8s-master controller]#

27 [root@k8s-master controller]# cat nginx-deployment-1.17.5.yaml

28 apiVersion: apps/v1

29kind: Deployment

30metadata:

31 name: nginx-deployment

32 labels:

33 app: nginx

34spec:

35 replicas: 3

36 # 重点关注该字段

37 selector:

38 matchLabels:

39 app: nginx

40 template:

41 metadata:

42 labels:

43 app: nginx

44 spec:

45 containers:

46 - name: nginx

47 image: registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5

48 ports:

49 - containerPort: 80

selector 字段定义 Deployment 如何查找要管理的 Pods。在这种情况下，会选择在 template（Pod）模板中定义的标签labels（app: nginx）。但更复杂的选择规则是可能的，只要 template （Pod）模板本身满足规则。

刚启动时状态说明

启动deployment，并查看状态

1 [root@k8s-master controller]# kubectl apply -f nginx-deployment-1.17.1.yaml --record
2 deployment.apps/nginx-deployment created
3 [root@k8s-master controller]#
4 [root@k8s-master controller]# kubectl get deployment -o wide
5 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR
6 nginx-deployment   2/332           10s   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx
7
8 # --record 参数可以记录命令，通过 kubectl rollout history deployment/nginx-deployment 可查询

参数说明：

NAME：列出集群中 Deployments 的名称

READY：已就绪副本数/期望副本数

UP-TO-DATE：显示已更新和正在更新中的副本数

AVAILABLE：显示应用程序可供用户使用的副本数

AGE：显示运行的时间

查看ReplicaSet状态

1 [root@k8s-master controller]# kubectl get rs -o wide
2NAME                          DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES                                                          SELECTOR
3 nginx-deployment-76b9d6bcf5   332       17s   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx,pod-template-hash=76b9d6bcf5

参数说明：

NAME：列出集群中 ReplicaSet的名称

DESIRED：期望副本数

CURRENT：当前副本数

READY：已就绪副本数

AGE：运行时间

查看pod状态

1 [root@k8s-master controller]# kubectl get pod -o wide
2NAME                                READY   STATUS              RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES
3 nginx-deployment-76b9d6bcf5-ngpg5   1/1     Running             0          26s   10.244.2.43   k8s-node02   <none>           <none>
4 nginx-deployment-76b9d6bcf5-rw827   1/1     Running             0          26s   10.244.2.44   k8s-node02   <none>           <none>
5 nginx-deployment-76b9d6bcf5-ttf4j   0/1     ContainerCreating   0          26s   <none>        k8s-node01   <none>           <none>

过一会儿状态说明

 1 [root@k8s-master controller]# kubectl get deployment -o wide --show-labels
 2 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR    LABELS
 3 nginx-deployment   3/333           23m   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx   app=nginx
 4 [root@k8s-master controller]#
 5 [root@k8s-master controller]# kubectl get rs -o wide --show-labels
 6NAME                          DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES                                                          SELECTOR                                 LABELS
 7 nginx-deployment-76b9d6bcf5   333       23m   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx,pod-template-hash=76b9d6bcf5   app=nginx,pod-template-hash=76b9d6bcf5
 8 [root@k8s-master controller]#
 9 [root@k8s-master controller]# kubectl get pod -o wide --show-labels
10NAME                                READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
11 nginx-deployment-76b9d6bcf5-ngpg5   1/1     Running   0          23m   10.244.2.43   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=76b9d6bcf5
12 nginx-deployment-76b9d6bcf5-rw827   1/1     Running   0          23m   10.244.2.44   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=76b9d6bcf5
13 nginx-deployment-76b9d6bcf5-ttf4j   1/1     Running   0          23m   10.244.4.37   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=76b9d6bcf5

重点说明

1、ReplicaSet 的名称始终被格式化为[DEPLOYMENT-NAME]-[RANDOM-STRING]。随机字符串是随机生成，并使用 pod-template-hash 作为选择器和标签。

2、Deployment 控制器将 pod-template-hash 标签添加到 Deployment 创建或使用的每个 ReplicaSet 。此标签可确保 Deployment 的子 ReplicaSets 不重叠。因此不可修改。

3、注意Deployment、ReplicaSet和Pod三者的名称关系

更新 Deployment

Deployment 可确保在更新时仅关闭一定数量的 Pods。默认情况下，它确保至少 75%所需 Pods 运行（25%最大不可用）。

Deployment 更新过程中还确保仅创建一定数量的 Pods 且高于期望的 Pods 数。默认情况下，它可确保最多增加 25% 期望 Pods 数（25%最大增量）。

备注：实际操作中如果更新Deployment，那么最好通过yaml文件更新，这样回滚到任何版本都非常便捷，而且更容易追述；而不是通过命令行。

如下Deployment示例，由于只有3个副本。因此更新时不会先删除旧的pod，而是先新建一个pod。新pod运行时，才会删除对应老的pod。一切的前提都是为了满足上述的条件。

需求：更新 nginx Pods，从当前的1.17.1版本改为1.17.5版本。

 1# 方式一
 2 kubectl edit deployment/nginx-deployment    # 然后修改 image 镜像信息 【不推荐】
 3 # 上述方法不会记录命令，通过kubectl rollout history deployment/nginx-deployment 无法查询
 4
 5# 方式二如下【可使用】：
 6 kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5 --record
 7
 8# 方式三如下【推荐★★★★★】
 9 kubectl apply -f nginx-deployment-1.17.5.yaml --record
10
11 # --record 参数可以记录命令，通过 kubectl rollout history deployment/nginx-deployment 可查询

要查看更新状态

 1 [root@k8s-master controller]# kubectl rollout status deployment/nginx-deployment
 2# 如没有更新完成，则显示更新过程直到更新成功
 3 Waiting for deployment "nginx-deployment" rollout to finish: 1 out of 3 new replicas have been updated...
 4 Waiting for deployment "nginx-deployment" rollout to finish: 1 out of 3 new replicas have been updated...
 5 Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
 6 Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
 7 Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
 8 Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
 9 Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
10 deployment "nginx-deployment" successfully rolled out
11# 如已更新完毕，直接显示更新成功
12 deployment "nginx-deployment" successfully rolled out

更新中的Deployment、ReplicaSet、Pod信息

 1 [root@k8s-master controller]# kubectl get deployment -o wide --show-labels
 2 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR    LABELS
 3 nginx-deployment   3/313           12m   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx   app=nginx
 4 [root@k8s-master controller]#
 5 [root@k8s-master controller]# kubectl get rs -o wide --show-labels
 6NAME                          DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES                                                          SELECTOR                                 LABELS
 7 nginx-deployment-56d78686f5   110       23s   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx,pod-template-hash=56d78686f5   app=nginx,pod-template-hash=56d78686f5
 8 nginx-deployment-76b9d6bcf5   333       12m   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx,pod-template-hash=76b9d6bcf5   app=nginx,pod-template-hash=76b9d6bcf5
 9 [root@k8s-master controller]#
10 [root@k8s-master controller]# kubectl get pod -o wide --show-labels
11NAME                                READY   STATUS              RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
12 nginx-deployment-56d78686f5-4kn4c   0/1     ContainerCreating   0          30s   <none>        k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
13 nginx-deployment-76b9d6bcf5-7lcr9   1/1     Running             0          12m   10.244.4.41   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=76b9d6bcf5
14 nginx-deployment-76b9d6bcf5-jbb5h   1/1     Running             0          12m   10.244.2.48   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=76b9d6bcf5
15 nginx-deployment-76b9d6bcf5-rt4m7   1/1     Running             0          12m   10.244.4.42   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=76b9d6bcf5

更新成功后的Deployment、ReplicaSet、Pod信息

 1 [root@k8s-master controller]# kubectl get deployment -o wide --show-labels
 2 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR    LABELS
 3 nginx-deployment   3/333           15m   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx   app=nginx
 4 [root@k8s-master controller]#
 5 [root@k8s-master controller]# kubectl get rs -o wide --show-labels
 6NAME                          DESIRED   CURRENT   READY   AGE     CONTAINERS   IMAGES                                                          SELECTOR                                 LABELS
 7 nginx-deployment-56d78686f5   333       3m23s   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx,pod-template-hash=56d78686f5   app=nginx,pod-template-hash=56d78686f5
 8 nginx-deployment-76b9d6bcf5   000       15m     nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx,pod-template-hash=76b9d6bcf5   app=nginx,pod-template-hash=76b9d6bcf5
 9 [root@k8s-master controller]#
10 [root@k8s-master controller]# kubectl get pod -o wide --show-labels
11NAME                                READY   STATUS    RESTARTS   AGE     IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
12 nginx-deployment-56d78686f5-4kn4c   1/1     Running   0          3m25s   10.244.2.49   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
13 nginx-deployment-56d78686f5-khsnm   1/1     Running   0          100s    10.244.2.50   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
14 nginx-deployment-56d78686f5-t24qw   1/1     Running   0          2m44s   10.244.4.43   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=56d78686f5

通过查询Deployment详情，知晓pod替换过程

 1 [root@k8s-master controller]# kubectl describe deploy nginx-deployment
 2 Name:                   nginx-deployment
 3Namespace:              default
 4 CreationTimestamp:      Thu, 28 May 202000:04:09 +0800
 5 Labels:                 app=nginx
 6 Annotations:            deployment.kubernetes.io/revision: 2
 7                         kubectl.kubernetes.io/last-applied-configuration:
 8                           {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{"kubernetes.io/change-cause":"kubectl apply --filename=nginx-deploy...
 9                         kubernetes.io/change-cause:
10                           kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5 --record=true
11 Selector:               app=nginx
12 Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
13StrategyType:           RollingUpdate
14 MinReadySeconds:        0
15 RollingUpdateStrategy:  25% max unavailable, 25% max surge
16Pod Template:
17   Labels:  app=nginx
18  Containers:
19   nginx:
20     Image:        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5
21     Port:         80/TCP
22     Host Port:    0/TCP
23     Environment:  <none>
24     Mounts:       <none>
25   Volumes:        <none>
26Conditions:
27  Type           Status  Reason
28   ----           ------  ------
29  Available      True    MinimumReplicasAvailable
30  Progressing    True    NewReplicaSetAvailable
31 OldReplicaSets:  <none>
32 NewReplicaSet:   nginx-deployment-56d78686f5 (3/3 replicas created)
33Events:
34  Type    Reason             Age   From                   Message
35   ----    ------             ----  ----                   -------
36   Normal  ScalingReplicaSet  93s   deployment-controller  Scaled up replica set nginx-deployment-76b9d6bcf5 to 3
37   Normal  ScalingReplicaSet  38s   deployment-controller  Scaled up replica set nginx-deployment-56d78686f5 to 1
38   Normal  ScalingReplicaSet  37s   deployment-controller  Scaled down replica set nginx-deployment-76b9d6bcf5 to 2
39   Normal  ScalingReplicaSet  37s   deployment-controller  Scaled up replica set nginx-deployment-56d78686f5 to 2
40   Normal  ScalingReplicaSet  35s   deployment-controller  Scaled down replica set nginx-deployment-76b9d6bcf5 to 1
41   Normal  ScalingReplicaSet  35s   deployment-controller  Scaled up replica set nginx-deployment-56d78686f5 to 3
42   Normal  ScalingReplicaSet  34s   deployment-controller  Scaled down replica set nginx-deployment-76b9d6bcf5 to 0

多 Deployment 动态更新

当 Deployment 正在展开进行更新时，Deployment 会为每个更新创建一个新的 ReplicaSet 并开始向上扩展，之前的 ReplicaSet 会被添加到旧 ReplicaSets 队列并开始向下扩展。

例如，假设创建一个 Deployment 以创建 nginx:1.7.9 的 5 个副本，然后更新 Deployment 以创建 5 个 nginx:1.9.1 的副本，而此时只有 3 个nginx:1.7.9 的副本已创建。在这种情况下， Deployment 会立即开始杀死3个 nginx:1.7.9 Pods，并开始创建 nginx:1.9.1 Pods。它不等待 nginx:1.7.9 的 5 个副本完成后再更新为nginx:1.9.1。

回滚 Deployment

yaml文件方式

针对应用的每个镜像版本，都有对应deploy的yaml文件。不管是升级还是回滚都已轻松应对。如下

1 nginx-deployment-1.15.6.yaml
2 nginx-deployment-1.17.yaml
3 nginx-deployment-1.17.1.yaml
4 nginx-deployment-1.17.5.yaml

yaml文件中的信息，参考上文即可。

命令行方式

问题产生

假设在更新 Deployment 时犯了一个拼写错误，将镜像名称命名为了 nginx:1.1710 而不是 nginx:1.17.10

1 [root@k8s-master controller]# kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.1710 --record
2 deployment.apps/nginx-deployment image updated

查看Deployment、ReplicaSet、Pod信息

 1 [root@k8s-master controller]# kubectl get deploy -o wide --show-labels
 2 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR    LABELS
 3 nginx-deployment   3/313           14m   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.1710   app=nginx   app=nginx
 4 [root@k8s-master controller]#
 5 [root@k8s-master controller]# kubectl get rs -o wide --show-labels
 6NAME                          DESIRED   CURRENT   READY   AGE     CONTAINERS   IMAGES                                                          SELECTOR                                 LABELS
 7 nginx-deployment-55c7bdfb86   333       9m19s   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17     app=nginx,pod-template-hash=55c7bdfb86   app=nginx,pod-template-hash=55c7bdfb86
 8 nginx-deployment-56d78686f5   000       12m     nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx,pod-template-hash=56d78686f5   app=nginx,pod-template-hash=56d78686f5
 9 nginx-deployment-76b9d6bcf5   000       13m     nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx,pod-template-hash=76b9d6bcf5   app=nginx,pod-template-hash=76b9d6bcf5
10 nginx-deployment-844d7bbb7f   110       64s     nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.1710   app=nginx,pod-template-hash=844d7bbb7f   app=nginx,pod-template-hash=844d7bbb7f
11 [root@k8s-master controller]#
12 [root@k8s-master controller]# kubectl get pod -o wide --show-labels
13NAME                                READY   STATUS             RESTARTS   AGE    IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
14 nginx-deployment-55c7bdfb86-bwzk9   1/1     Running            0          10m    10.244.4.49   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=55c7bdfb86
15 nginx-deployment-55c7bdfb86-cmvzg   1/1     Running            0          10m    10.244.2.55   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=55c7bdfb86
16 nginx-deployment-55c7bdfb86-kjrrw   1/1     Running            0          10m    10.244.2.56   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=55c7bdfb86
17 nginx-deployment-844d7bbb7f-pctwr   0/1     ImagePullBackOff   0          2m3s   10.244.4.51   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=844d7bbb7f

需求：回滚到以前稳定的 Deployment 版本。

操作步骤如下：

检查 Deployment 修改历史

1 [root@k8s-master controller]# kubectl rollout history deployment/nginx-deployment
2 deployment.apps/nginx-deployment
3 REVISION  CHANGE-CAUSE
41         kubectl apply --filename=nginx-deployment.yaml --record=true
52         kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5 --record=true
63         kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17 --record=true
74         kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.1710 --record=true

查看修改历史的详细信息，运行

1 [root@k8s-master controller]# kubectl rollout history deployment/nginx-deployment --revision=3

2 deployment.apps/nginx-deployment with revision #3

3Pod Template:

4 Labels: app=nginx

5 pod-template-hash=55c7bdfb86

6 Annotations: kubernetes.io/change-cause:

7 kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17 --record=true

8 Containers:

9 nginx:

10 Image: registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17

11 Port: 80/TCP

12 Host Port: 0/TCP

13 Environment: <none>

14 Mounts: <none>

15 Volumes: <none>

回滚到上一次修改（即版本 3）或指定版本

现在已决定撤消当前更新并回滚到以前的版本

1# 回滚到上一版本
2 [root@k8s-master controller]# kubectl rollout undo deployment/nginx-deployment
3 deployment.apps/nginx-deployment rolled back
4# 回滚到指定历史版本
5 [root@k8s-master controller]# kubectl rollout undo deployment/nginx-deployment --to-revision=2
6 deployment.apps/nginx-deployment rolled back

检查回滚是否成功、 Deployment 是否正在运行

1 [root@k8s-master controller]# kubectl get deploy -o wide --show-labels
2 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR    LABELS
3 nginx-deployment   3/333           17h   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx   app=nginx

获取 Deployment 描述信息

 1 [root@k8s-master controller]# kubectl describe deployment
 2 Name:                   nginx-deployment
 3Namespace:              default
 4 CreationTimestamp:      Thu, 28 May 202000:04:09 +0800
 5 Labels:                 app=nginx
 6 Annotations:            deployment.kubernetes.io/revision: 7
 7                         kubectl.kubernetes.io/last-applied-configuration:
 8                           {"apiVersion":"apps/v1","kind":"Deployment","metadata":{"annotations":{"kubernetes.io/change-cause":"kubectl apply --filename=nginx-deploy...
 9                         kubernetes.io/change-cause:
10                           kubectl set image deployment/nginx-deployment nginx=registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5 --record=true
11 Selector:               app=nginx
12 Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
13StrategyType:           RollingUpdate
14 MinReadySeconds:        0
15 RollingUpdateStrategy:  25% max unavailable, 25% max surge
16Pod Template:
17   Labels:  app=nginx
18  Containers:
19   nginx:
20     Image:        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5
21     Port:         80/TCP
22     Host Port:    0/TCP
23     Environment:  <none>
24     Mounts:       <none>
25   Volumes:        <none>
26Conditions:
27  Type           Status  Reason
28   ----           ------  ------
29  Available      True    MinimumReplicasAvailable
30  Progressing    True    NewReplicaSetAvailable
31 OldReplicaSets:  <none>
32 NewReplicaSet:   nginx-deployment-56d78686f5 (3/3 replicas created)
33Events:
34  Type    Reason             Age                 From                   Message
35   ----    ------             ----                ----                   -------
36………………
37   Normal  ScalingReplicaSet  107s                deployment-controller  Scaled up replica set nginx-deployment-56d78686f5 to 1
38   Normal  ScalingReplicaSet  104s                deployment-controller  Scaled down replica set nginx-deployment-55c7bdfb86 to 2
39   Normal  ScalingReplicaSet  104s                deployment-controller  Scaled up replica set nginx-deployment-56d78686f5 to 2
40   Normal  ScalingReplicaSet  103s                deployment-controller  Scaled down replica set nginx-deployment-55c7bdfb86 to 1
41   Normal  ScalingReplicaSet  103s                deployment-controller  Scaled up replica set nginx-deployment-56d78686f5 to 3
42   Normal  ScalingReplicaSet  102s                deployment-controller  Scaled down replica set nginx-deployment-55c7bdfb86 to 0

扩容/缩容Deployment

操作过程如下

 1 [root@k8s-master controller]# kubectl scale deployment/nginx-deployment --replicas=10
 2 deployment.apps/nginx-deployment scaled
 3 [root@k8s-master controller]# kubectl get deploy -o wide --show-labels
 4 NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES                                                          SELECTOR    LABELS
 5 nginx-deployment   10/101010          17h   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx   app=nginx
 6 [root@k8s-master controller]#
 7 [root@k8s-master controller]# kubectl get rs -o wide --show-labels
 8NAME                          DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES                                                          SELECTOR                                 LABELS
 9 nginx-deployment-55c7bdfb86   000       17h   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17     app=nginx,pod-template-hash=55c7bdfb86   app=nginx,pod-template-hash=55c7bdfb86
10 nginx-deployment-56d78686f5   101010      17h   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.5   app=nginx,pod-template-hash=56d78686f5   app=nginx,pod-template-hash=56d78686f5
11 nginx-deployment-76b9d6bcf5   000       17h   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.17.1   app=nginx,pod-template-hash=76b9d6bcf5   app=nginx,pod-template-hash=76b9d6bcf5
12 nginx-deployment-844d7bbb7f   000       17h   nginx        registry.cn-beijing.aliyuncs.com/google_registry/nginx:1.1710   app=nginx,pod-template-hash=844d7bbb7f   app=nginx,pod-template-hash=844d7bbb7f
13 [root@k8s-master controller]#
14 [root@k8s-master controller]# kubectl get pod -o wide --show-labels
15NAME                                READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES   LABELS
16 nginx-deployment-56d78686f5-4v5mj   1/1     Running   0          44s   10.244.2.64   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
17 nginx-deployment-56d78686f5-8m7mx   1/1     Running   0          44s   10.244.4.60   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
18 nginx-deployment-56d78686f5-c7wlb   1/1     Running   0          44s   10.244.4.59   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
19 nginx-deployment-56d78686f5-jg5lt   1/1     Running   0          44s   10.244.2.63   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
20 nginx-deployment-56d78686f5-jj58d   1/1     Running   0          11m   10.244.4.56   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
21 nginx-deployment-56d78686f5-k2kts   1/1     Running   0          11m   10.244.4.57   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
22 nginx-deployment-56d78686f5-qltkv   1/1     Running   0          44s   10.244.2.61   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
23 nginx-deployment-56d78686f5-r7vmm   1/1     Running   0          11m   10.244.2.60   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
24 nginx-deployment-56d78686f5-rxlpm   1/1     Running   0          44s   10.244.2.62   k8s-node02   <none>           <none>            app=nginx,pod-template-hash=56d78686f5
25 nginx-deployment-56d78686f5-vlzrf   1/1     Running   0          44s   10.244.4.58   k8s-node01   <none>           <none>            app=nginx,pod-template-hash=56d78686f5