
VirtualBox is open-source and cross-platform virtualization software that allows you to run multiple guest operating systems. The Guest Additions provides some useful functionalities for guest machines like a mouse pointer integration, full screen view, shared folders, shared clipboard, better and accelerated and much more. In this guide, described how to install VirtualBox Guest Additions on CentOS 8 guests.
Installing Guest Additions on CentOS 8 Guest
VirtualBox guest additions can be installed using VirtualBox guest addition ISO file. That inlcudes guest additions installers for all supported guest operating systems. The Guest additions ISO file can be mounted on a VirtualBox virtual machine via the Virtualbox manager or by installing with the package manager.
Perform the following steps to install VirtualBox guest additions on CentOS desktop or server guest.
1. Open the VirtualBox GUI Manager.
2. Start the CentOS guest virtual machine.
3. Log in to the guest machine as root or sudo user. Run below command to install the packages required for building kernel modules:
sudo dnf install gcc kernel-devel kernel-headers dkms make bzip2 perl
4. Open the virtual machine and click Devices > Insert Guest Additions CD image
on the Menu bar.

5. To mount the ISO file, create a new directory using CentOS terminal:
sudo mkdir -p /mnt/cdrom
sudo mount /dev/cdrom /mnt/cdrom
6. Go to that directory and run VBoxLinuxAdditions.run
script to install the Guest Additions:
cd /mnt/cdrom
sudo sh ./VBoxLinuxAdditions.run
It will show output like below:
Verifying archive integrity... All good. Uncompressing VirtualBox 6.0.16 Guest Additions for Linux…….. ... VirtualBox Guest Additions: Starting.
7. Reboot the CentOS guest for changes to take effect:
sudo shutdown -r now
8. Verify the installation once the virtual machine is booted, run the below command to check:
lsmod | grep vboxguest
vboxguest 348160 2 vboxsf
If it will not return any output means that the VirtualBox kernel module is not loaded.
Well, that is it. You have installed VirtualBox Guest Additions on your CentOS guest machine.
You can now enable mouse pointer integration, shared clipboard, shared folders, etc. from the virtual machine settings.
Conclusion
You learned step by step how to install VirtualBox Guest Additions on your CentOS 8 guest machine. Visit VirtualBox Guest Additions documentation page to know more.
If you have any questions, please leave a comment below.
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