yum更新出错-解决

Total download size: 14 M
Is this ok [y/d/N]:

命令里已经yum install -y了，但是还是需要选择Y,N没有自动执行，请问这个要怎么破。

PS：我是在Dockerfile里设置，然后进入镜像手动测试，Dockerfile报错如下：

Is this ok [y/d/N]: Exiting on user command
Your transaction was saved, rerun it with:
yum load-transaction /tmp/yum_save_tx.2018-02-01.02-10.O1ZlZ_.yumtx
The command '/bin/sh -c yum update && yum install telnet -y' returned a non-zero code: 1

需要执行：

yum update -y && yum install telnet -y

说明yum update过程中需要确认