查看当前有哪些版本，可以看到1和2 

[root@k8s-master-61 ~]# kubectl rollout history deployment/scm-admin -n java-test2
deployment.apps/scm-admin 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>

查看版本1  

[root@k8s-master-61 ~]# kubectl rollout history deployment/scm-admin -n java-test2  --revision=1
deployment.apps/scm-admin with revision #1
Pod Template:
  Labels:	app=scm-admin
	pod-template-hash=844d49f654
  Containers:
   scm-admin:
    Image:	10.1.1.247/datacenter/scm-admin:master-2021-07-08
    Port:	9015/TCP
    Host Port:	0/TCP
    Limits:
      cpu:	1
      memory:	1Gi
    Requests:
      cpu:	500m
      memory:	500Mi
    Environment:	<none>
    Mounts:
      /usr/share/zoneinfo/Asia/Shanghai from date (ro)
  Volumes:
   date:
    Type:	HostPath (bare host directory volume)
    Path:	/etc/localtime
    HostPathType:	

版本2 

[root@k8s-master-61 ~]# kubectl rollout history deployment/scm-admin -n java-test2  --revision=2
deployment.apps/scm-admin with revision #2
Pod Template:
  Labels:	app=scm-admin
	pod-template-hash=78769698bf
  Containers:
   scm-admin:
    Image:	10.1.1.247/datacenter/scm-admin:master-2021-07-12
    Port:	9015/TCP
    Host Port:	0/TCP
    Limits:
      cpu:	1
      memory:	1Gi
    Requests:
      cpu:	500m
      memory:	500Mi
    Environment:	<none>
    Mounts:
      /usr/share/zoneinfo/Asia/Shanghai from date (ro)
  Volumes:
   date:
    Type:	HostPath (bare host directory volume)
    Path:	/etc/localtime
    HostPathType:	

我们可以看到当前处于版本2，现在我们回滚到版本1 

[root@k8s-master-61 ~]# kubectl rollout undo deployment/scm-admin -n java-test2  --to-revision=1
deployment.apps/scm-admin rolled back

现在默认创建3 ，也就是之前的1

[root@k8s-master-61 ~]# kubectl get pods -n java-test2
NAME                            READY   STATUS             RESTARTS   AGE
busybox-548b94bcd4-5p796        1/1     Running            93         3d22h
scm-admin-844d49f654-7xg6z      1/1     Running            0          58s
scm-admin-844d49f654-g9khj      1/1     Running            0          60s
scm-finance-88fd7d86f-nxhkt     1/1     Running            0          4d3h
scm-log-665c8689bb-p5cvj        1/1     Running            0          3d23h
scm-open-6c99d97878-ttc4k       0/1     ImagePullBackOff   0          4d
scm-purchase-f6b577b86-cpmz4    1/1     Running            0          3d23h
scm-report-669b5bdd87-j652f     1/1     Running            0          3d23h
scm-stock-84846575c9-rww2g      1/1     Running            0          4d3h
scm-system-55f7dbbcff-fnjtk     1/1     Running            0          4d3h
scm-tenant-556865887-skt78      1/1     Running            0          4d3h
scm-warehouse-99d7dc885-6jpqb   1/1     Running            0          4d3h
supply-user-5c845b6846-69k24    1/1     Running            0          3d3h
[root@k8s-master-61 ~]# kubectl rollout history deployment/scm-admin -n java-test2
deployment.apps/scm-admin 
REVISION  CHANGE-CAUSE
2         <none>
3         <none>

 默认回滚到上一个版本，不指定--to-revision=？   则默认回滚到上一版本

[root@k8s-master-61 ~]# kubectl rollout undo deployment/scm-admin -n java-test2  
deployment.apps/scm-admin rolled back

revisionHistoryLimit：3  保留3个版本