问题
具体报错信息如下：
repository are already installed but they are not correct for this package.
Check that the correct key URLs are configured for this repository.例如，在CentOS 6.8上安装 percona
yum install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm
yum list | grep percona
yum install percona-toolkit最后一步报错，报错信息如下所示：
warning: rpmts_HdrFromFdno: Header V4 RSA/SHA256 Signature, key ID 8507efa5: NOKEY
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-Percona
The GPG keys listed for the "Percona-Release YUM repository - x86_64" repository are already installed but they are not correct for this package.
Check that the correct key URLs are configured for this repository.解决方案
安装现有的 gpg 公钥，在 /etc/pki/rpm-gpg/ 下，可以执行如下命令直接把所有的都安装上
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*如果还是不行，就通过参数指定不检查数字签名，如下所示。
yum -y install * --nogpgcheck所以，解决安装 percona报错可以使用如下命令解决
yum install percona-toolkit --nogpgcheck