This is guide, howto install Oracle VirtualBox Guest Additions on Fedora, CentOS and Red Hat (RHEL).    
    This guide should work with Fedora 17/16/15/14/13/12, CentOS 6.3/6.2/6.1/6.0/5.8, Red Hat (RHEL) 6.3/6.2/6.1/6/5.8.
    VirtualBox Guest Additions is special software that can be installed inside Linux virtual machines to improve performance and make integration much more seamless. Among the features provided by these VirtualBox Guest Additions are mouse pointer integration and arbitrary screen solutions (e.g. by resizing the guest window).

Install VirtualBox Guest Additions on Fedora, CentOS and Red Hat (RHEL)

//在CentOS和RedHat上安装Virtualbox
增强功能

1. Change root user

//切换到超级用户 
 
      
 
     
 
     
 
    
 2. Mount VirtualBox Guest Additions 
    
      //挂在 Virtualbox 
     增强功能镜像 
    
 
    
      Click 
     Devices > Install Guest Additions… on VirtualBox 
    
 
    
3. Make sure that you are running latest kernel
 
    
      //确保你运行最新的内核 
     
 
    
 
    
      Update virtual machine kernel and reboot 
    
 
    
      //升级虚拟机内核并重启 
     
 
     
 
      
 
       yum update kernel* 
reboot 
      
 
     
 
     
 
    
 
    
4. Install following packages
 
    
      //安装下列包 
     
 
    
 
    
 
     
 
     
 
      
 
     
 
     
 
    
 
    
5. Add KERN_DIR environment variable
 
    
      //添加KERN_DIR环境变量 
     
 
    
 
    
 
     
 
     
 
      
 
     
 
     
 
    
 
    
6. Install Guest Additions
 
    
      //安装 Virtualbox 
     增强功能 
    
 
    
 
     //这是我自己做的和原文不同
 
    
 
    
      （1） 
     
 
      
    
 
    
      （2） 
     
 
      
    
 
    
 
     
 
    
 
    
      (3) 
     
 
      Output looks like following: 
    
 
    
 
    
7. Reboot guest system
 
    
      //重启系统 
     
 
    
 
    
 
     reboot 
     
 
     
 
    
 
    
 
     Then VirtualBox Guest Additions install is ready.