mount -t vboxsf tools /mnt/share

报错了：/sbin/mount.vboxsf: mounting failed with the error: No such device

解决办法：

yum clean all
yum update
yum install kernel
yum install kernel-devel
yum install kernel-headers
yum install gcc
yum install make  
reboot

 

cd /opt/VBoxGuestAdditions-*/init  
./vboxadd setup
reboot

也可以先尝试不更新，直接执行上面的安装命令