https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to download.docker.com:443; 操作现在正在进行" 正在尝试其它镜像。

[root@adm ~]# sudo yum makecache
已加载插件：fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
base                                                                         | 3.6 kB  00:00:00    
https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to download.docker.com:443; 操作现在正在进行"
正在尝试其它镜像。
https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to download.docker.com:443; 操作现在正在进行"
正在尝试其它镜像。
https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to download.docker.com:443; 操作现在正在进行"
正在尝试其它镜像。
https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to download.docker.com:443; 操作现在正在进行"
正在尝试其它镜像。
https://download.docker.com/linux/centos/7/x86_64/stable/repodata/repomd.xml: [Errno 14] curl#7 - "Failed connect to download.docker.com:443; 操作现在正在进行"
正在尝试其它镜像。

切换源后出现后，执行下面的任意一个命令就行

# 阿里源
yum-config-manager \
    --add-repo \
    http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# or
# 清华源
yum-config-manager \
    --add-repo \
    https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/centos/docker-ce.repo