1.百度中提供的安裝辦法

yum install epel-release -y
yum install dnf

2. No package dnf available解決辦法

運行一下幾個命令：

wget http://springdale.math.ias.edu/data/puias/unsupported/7/x86_64/dnf-conf-0.6.4-2.sdl7.noarch.rpm
wget http://springdale.math.ias.edu/data/puias/unsupported/7/x86_64//dnf-0.6.4-2.sdl7.noarch.rpm
wget http://springdale.math.ias.edu/data/puias/unsupported/7/x86_64/python-dnf-0.6.4-2.sdl7.noarch.rpm
yum install python-dnf-0.6.4-2.sdl7.noarch.rpm  dnf-0.6.4-2.sdl7.noarch.rpm dnf-conf-0.6.4-2.sdl7.noarch.rpm
 

安裝之後執行以下命令：

dnf --version 

輸出：

0.6.4                                                                                                                          
Repository epel is listed more than once in the configuration                                                                  
  Installed: dnf-0:0.6.4-2.sdl7.noarch at 2018-03-09 11:31                                                                     
  Built    :  at 2016-10-09 17:18                                                                                              
                                                                                                                               
  Installed: rpm-0:4.11.3-25.el7.x86_64 at 2018-01-09 10:21                                                                    
  Built    : CentOS BuildSystem <http://bugs.centos.org> at 2017-08-03 03:48
 

安裝成功。

CentOS7安裝dnf報錯：No package dnf available