When a guest system is installed on VirtualBox, several features are usually disabled or missing. In addition, the screen size is usually scaled-down instead of being full screen and this, among many other shortcomings, impacts the overall user experience. VirtualBox Guest Additions is a set of device drivers and applications which are designed to help achieve enhanced usability and improve the overall user experience of the guest system.

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to perform related VirtualBox queries on any Linux system.

In this context, we shall look into how to install the VirtualBox guest additions in Debian 11.

Main features of VirtualBox guest Additions includes:

• Shared clipboard between the guest vm and the host system.
• Smooth mouse pointer integration.
• Enhanced and accelerated video performance.
• Shared folders which enable sharing of files and directories between host and guest
• Time synchronization between the host and the guest.
• Additional generic communication channels that offer better control of the guest by the user.

Steps to install VirtualBox Guest Additions on Debian

Before proceeding with the procedure, ensure that you have a sudo user already configured on your virtual machine instance.

Also note that you need to have installed Debian 11 on VirtualBox hypervisor before you can perform the below outlined steps. 

1. Update Debian 11 system

It's always a good idea to begin by updating the system by upgrading all the packages. But first, refresh the package lists.

So to do this, simply run the system update command:

$ sudo apt update

Next upgrade the system including the kernel and existing packages:

$ sudo apt upgrade

2. Install dependencies

To install VirtualBox, a few dependencies are required. You need to install the DKMS (Dynamic kernel Module Support) program that is used for generating kernel modules, the kernel headers, and build tools:

$ sudo apt install dkms linux-headers-$(uname -r) build-essential

This command installs Linux headers , compiler tools, and several other packages.

3. Install VirtualBox Guest Additions

Once the installation of the dependencies is done, head back to the Virtual machine's control panel and hit the 'Settings' tab.

Navigate and hit 'Devices' and from the pull-down menu, select the 'Insert Guest Additions CD Image' option.

This inserts the VirtualBox Guest Addition ISO file on the guest machine. You can verify this by launching the File Manager and navigating to the left sidebar.

The next step is to mount it in /mnt directory as shown:

$ sudo mount /dev/cdrom /mnt

You can confirm the contents as follows using the ls command:

$ ls -l /mnt

Of interest is the VBoxLinuxAdditions.run script. This is what we need to run. So, navigate to the /mnt directory:

$ cd /mnt

And run the installation script:

$ sudo ./VBoxLinuxAdditions.run 

Finally, restart your Debian 11 instance to finish running the Guest Additions kernel modules:

$ sudo reboot 

When you log in, you'll notice that your guest has scaled to full screen. You can now enjoy other features provided by the Guest Additions such as shared clipboard and file sharing with the host system.

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