＃yum install kernel-source
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.
解决方法是
执行 rpm --import /path/to/gpg.key
我这里是redhat，
rpm --import /usr/share/rhn/RPM-GPG-KEY