Usage:  kubectl scale --replicas=COUNT TYPE NAME [options]
Man:    对资源进行扩缩容，即修改副本数

[root@hdss7-21 ~]# kubectl get deploy web-deploy
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
web-deploy   2/2     2            2           37m
[root@hdss7-21 ~]# kubectl scale --replicas=5 deployment web-deploy  # 扩容
[root@hdss7-21 ~]# kubectl get deploy web-deploy
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
web-deploy   3/5     5            3           38m
[root@hdss7-21 ~]# kubectl scale --replicas=1 deployment web-deploy  # 缩容
[root@hdss7-21 ~]# kubectl get deploy web-deploy
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
web-deploy   1/1     1            1           38m