1.安装依赖包
yum -y install http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm
如果yum不能直接安装，可以先把rpm文件下载下来：
wget http://www.percona.com/downloads/percona-release/redhat/0.1-4/percona-release-0.1-4.noarch.rpm
yum -y install percona-release-0.1-4.noarch.rpm
2、测试依赖库是否安装成功(可能有点慢)：
yum list | grep percona
看到以下内容的输出即可确认安装成功：
3、安装percona，安装是如果有什么依赖，先安装即可；
上传：wget https://www.percona.com/downloads/XtraBackup/Percona-XtraBackup-2.4.9/binary/redhat/7/x86_64/percona-xtrabackup-24-2.4.9-1.el7.x86_64.rpm
安装：yum -y install percona-xtrabackup-24-2.4.9-1.el7.x86_64.rpm
4、查看：rpm -ql percona-xtrabackup-24或者xtrabackup --version
5、mysql5.7.20需安装最新版XtraBackup2.4.9
wget https://www.percona.com/downloads/XtraBackup/Percona-XtraBackup-2.4.9/binary/redhat/7/x86_64/Percona-XtraBackup-2.4.9-ra467167cdd4-el7-x86_64-bundle.tar
tar -xvf Percona-XtraBackup-2.4.9-ra467167cdd4-el7-x86_64-bundle.tar
yum -y install percona-xtrabackup-24-2.4.9-1.el7.x86_64.rpm
参考：https://www.cnblogs.com/linuxk/p/9372990.html