一次重裝CentOS7系統后，掛載光驅並制作成本地yum源卻無法使用yum進行安裝，這TM着實有點鬧心。o(>﹏<)o
案發現場：
[root@crntos7-server ~]# yum -y install /mnt/Packages/vsftpd-3.0.2-22.el7.x86_64.rpm
You have enabled checking of packages via GPG keys. This is a good thing.
However, you do not have any GPG public keys installed. You need to download
the keys for packages you wish to install and install them.
You can do that by running the command:
rpm --import public.gpg.key
Alternatively you can specify the url to the key you would like to use
for a repository in the 'gpgkey' option in a repository section and yum
will install it for you.
For more information contact your distribution or package provider.
解決方法：
[root@crntos7-server ~]# rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
[root@crntos7-server ~]# yum -y install /mnt/Packages/httpd-2.4.6-67.el7.centos.x86_64.rpm
Examining /mnt/Packages/httpd-2.4.6-67.el7.centos.x86_64.rpm: httpd-2.4.6-67.el7.centos.x86_64
Marking /mnt/Packages/httpd-2.4.6-67.el7.centos.x86_64.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package httpd.x86_64 0:2.4.6-67.el7.centos will be installed
--> Processing Dependency: httpd-tools = 2.4.6-67.el7.centos for package: httpd-2.4.6-67.el7.centos.x86_64
--> Processing Dependency: /etc/mime.types for package: httpd-2.4.6-67.el7.centos.x86_64
--> Processing Dependency: libapr-1.so.0()(64bit) for package: httpd-2.4.6-67.el7.centos.x86_64
--> Processing Dependency: libaprutil-1.so.0()(64bit) for package: httpd-2.4.6-67.el7.centos.x86_64
--> Running transaction check
---> Package apr.x86_64 0:1.4.8-3.el7 will be installed
---> Package apr-util.x86_64 0:1.5.2-6.el7 will be installed
---> Package httpd-tools.x86_64 0:2.4.6-67.el7.centos will be installed
............
用 rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY 導入 一般情況下
GPG KEY,一般系統都會有的,在你的linux安裝光盤目錄下，或者在/etc/pki/rpm-gpg/目錄下有一個 PM-GPG-KEY-CentOS-7
如果導入失敗 那么 可已將GPG.KEY路徑直接加入到你編輯的/etc/yum.repos.d/下的CentOS7.repo 保存退出
然后 yum makecache 元數據緩存創建
參考鏈接：https://www.cnblogs.com/goon2016vv/p/5625240.html