CentOS7 yum安装报错“Could not resolve host: mirrorlist.centos.org； Name or service not known“之解决办法（换源）

yum安装出现错误如下：

yum install -y wget && wget -O install.sh https://download.bt.cn/install/install_6.0.sh && sh install.sh 12f2c1d72

ImportError: /lib64/libcrypto.so.10: version `OPENSSL_1.0.2' not found (required by /www/server/panel/pyenv/lib/python3.7/lib-dynload/_ssl.cpython-37m-x86_64-linux-gnu.so)

Loaded plugins: fastestmirror, langpacks
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Name or service not known"

 One of the configured repositories failed (Unknown)

Loaded plugins: fastestmirror, langpacks
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Name or service not known"

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