virtualbox.org

1. every time there's a point release, do I need to reinstall Guest Additions (on the guest)? I see there's a 5.0.18 update from 5.0.16, but I have a bunch of VirtualBox machines running on 5.0.16, and all the guests have the guest additions installed (by mounting /usr/share/virtualbox/VBoxGuestAdditions.iso) . Now if I upgrade to 5.0.18 on the host, do I need to remount the ISO on my guests and reinstall?

2. I have some headless guests. I installed CentOS 7 minimal, installed guest additions by executing /dev/cdrom/VBoxLinuxAdditions.run. Everything went well, except for the comment about the "Not able to find X stuff, not installing" message, which makes sense because I have no X libraries installed.
However, on one of my guests, I want to go ahead install the X libraries, and install the guest additions modules for X. What do I do now? How do I do this? Should I just remount /usr/share/virtualbox/VBoxGuestAdditions.iso and rerun VBoxLinuxAdditions.run? Should I uninstall first and then reinstall everything again? What's the recommended procedure?

Thank you!

You don't need to uninstall & reinstall Guest Additions every time a new version comes out, unless some feature stops working. I have had a guest or two on 4.2.16 running 3.1.2 Guest Additions. But I wasn't using 2D/3D acceleration either, and they were XP/2003 guests, old steady OS's.

If you get a glitch, updating GAs is easy to see if that's the solution, but "if it aint broke don't fix it" should be OK for some time.

Re the new graphical interface for the headless guest, I'd uninstall the present GA's, add the graphical system, then install the new GAs. (for further info ask about this on the Linux Guests forum - I'm not a Linux guy yet.)