docker在線安裝錯誤提示：Could not resolve host.....

1.問題描述

參考docker官方安裝手冊安裝時，執行此yum安裝工具命令
出現以下報錯：

Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
device-mapper-1.02.158-2.el7_7 FAILED                                          
http://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/device-mapper-1.02.158-2.el7_7.2.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: mirrors.aliyun.com; Unknown error"
正在嘗試其它鏡像。
device-mapper-event-1.02.158-2 FAILED                                          
http://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/device-mapper-event-1.02.158-2.el7_7.2.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: mirrors.aliyun.com; Unknown error"
正在嘗試其它鏡像。
device-mapper-event-libs-1.02. FAILED                                          
http://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/device-mapper-event-libs-1.02.158-2.el7_7.2.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: mirrors.aliyun.com; Unknown error"
正在嘗試其它鏡像。
device-mapper-libs-1.02.158-2. FAILED                                          
http://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/device-mapper-libs-1.02.158-2.el7_7.2.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: mirrors.aliyun.com; Unknown error"
正在嘗試其它鏡像。
lvm2-2.02.185-2.el7_7.2.x86_64 FAILED                                          
http://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/lvm2-2.02.185-2.el7_7.2.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: mirrors.aliyun.com; Unknown error"
正在嘗試其它鏡像。
lvm2-libs-2.02.185-2.el7_7.2.x FAILED                                          
http://mirrors.aliyun.com/centos/7/updates/x86_64/Packages/lvm2-libs-2.02.185-2.el7_7.2.x86_64.rpm: [Errno 14] curl#6 - "Could not resolve host: mirrors.aliyun.com; Unknown error"
正在嘗試其它鏡像。

Error downloading packages:
  7:lvm2-libs-2.02.185-2.el7_7.2.x86_64: [Errno 256] No more mirrors to try.
  7:device-mapper-libs-1.02.158-2.el7_7.2.x86_64: [Errno 256] No more mirrors to try.
  7:device-mapper-event-1.02.158-2.el7_7.2.x86_64: [Errno 256] No more mirrors to try.
  7:device-mapper-event-libs-1.02.158-2.el7_7.2.x86_64: [Errno 256] No more mirrors to try.
  7:device-mapper-1.02.158-2.el7_7.2.x86_64: [Errno 256] No more mirrors to try.
  7:lvm2-2.02.185-2.el7_7.2.x86_64: [Errno 256] No more mirrors to try.

2.解決辦法

經過自己各種查找、嘗試(離線安裝法)，此問題和虛擬機DNS設置有關：
（1）首先利用查看ip的方式查看當前應該修改哪個配置文件

如上，我用的是ens33(每臺電腦都不大相同)
（2）接着找到如下命令對應位置(我這裏是ens33)，設置DNS1=8.8.8.8，最後重啓網絡service network restart 即可。

vim /etc/sysconfig/network-scripts/ifcfg-ens33