VirtualBox Guest Additions - CentOS Stream 9
Step 1 - Preparation
From VirtualBox Manager select the CentOS machine in the left panel.
Launch CentOS by clicking on the green Start arrow.
From Activities open a Terminal window.
Change to root by entering the following command:
$ sudo -i
When prompted, enter password.
Enter the following command:
$ dnf update
Enter the following command:
$ dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
When prompted enter y
When the process has finished, the Complete! message will display.
Enter the following command:
$ dnf install gcc kernel-devel kernel-headers make bzip2 perl
When prompted enter y and when prompted again enter y
From the Devices menu select Insert Guest Additions CD image...
Click the Run button.
Enter the password and click the Authenticate button.
When the process has completed, press enter to close the terminal window.
Reboot the machine by clicking on the top right icons and selecting Power Off / Log Out.
From the drop down, select Restart...
Click the Restart button.
When the machine reboots, log back in.
From the View menu select Full-screen Mode.
Click the Switch button.
