CentOS 8 is slated for release on September 24. So on that date:

• Update centos8.json to have the proper ISO and SHA-256 values.
• Build the VM locally, and test it using the included Vagrantfile.
• Push a 1.0.0 version up to Vagrant Cloud.
• Fix ansible uninstall in image build.

After completing issue #1, I had switched the install to use the DVD ISO instead of the boot.iso. I was having trouble with the boot.iso, namely I couldn't get it to either automatically choose a mirror, or accept any mirror manually entered (either via kickstart, via CLI directly, or via the GUI installer directly). I verified the VM had an active and working network connection (it showed as so in the installer, and in CLI I could ping google so DNS and TCP were happy).

I would like to use the boot.iso and do a network install instead of the dvd.iso since it's about 8x smaller and it's easier to download-while-installing since I don't need all 7+ GB of packages that are available in the DVD image.

When I executed:

packer build -var 'version=1.2.0' centos8.json

This happend:

virtualbox-iso: - downloading role 'packer-rhel', owned by geerlingguy

==> virtualbox-iso: [WARNING]: - geerlingguy.packer-rhel was NOT installed successfully: - sorry,
==> virtualbox-iso: geerlingguy.packer-rhel was not found on https://galaxy.ansible.com/api/.
==> virtualbox-iso: ERROR! - you can use --ignore-errors to skip failed roles and finish processing the list.
==> virtualbox-iso: Provisioning step had errors: Running the cleanup provisioner, if present...
==> virtualbox-iso: Deregistering and deleting VM...
==> virtualbox-iso: Deleting output directory...
Build 'virtualbox-iso' errored: Error executing Ansible: Error executing Ansible Galaxy: Non-zero exit status: 1

After completing Issue #1, I noticed the image size is just over 1 GB. If possible, I'd like to get it more in the 600-800 MB range, max. Maybe there really are 200 MB more things in CentOS 8 that are unavoidable, but I doubt it.

There might be more firmwares I don't need (I remember seeing the installer installing them along with 700+ other packages), or other things that are only necessary for a GUI install that are still getting installed off the 7 GB DVD iso.

Unless using this box with the vagrant-vbguest Vagrant plugin, you won't end up with Guest Additions being found (and even then, it looks like the installation fails. Something may be breaking during the installation.

When I started up box version 1.0.1, I got the following message:

[virtualbox] No Virtualbox Guest Additions installation found.
Last metadata expiration check: 4:12:38 ago on Thu 26 Sep 2019 08:24:43 PM UTC.
Package binutils-2.30-49.el8.x86_64 is already installed.
Package make-1:4.2.1-9.el8.x86_64 is already installed.
Package perl-4:5.26.3-416.el8.x86_64 is already installed.
Package bzip2-1.0.6-26.el8.x86_64 is already installed.
...
VirtualBox Guest Additions: or
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup all
VirtualBox Guest Additions: Building the modules for kernel 
4.18.0-80.7.1.el8_0.x86_64.

VirtualBox Guest Additions: Look at /var/log/vboxadd-setup.log to find out what 
went wrong
ValueError: File context for /opt/VBoxGuestAdditions-6.0.12/other/mount.vboxsf already defined
modprobe vboxguest failed
The log file /var/log/vboxadd-setup.log may contain further information.
An error occurred during installation of VirtualBox Guest Additions 6.0.12. Some functionality may not work as intended.
In most cases it is OK that the "Window System drivers" installation failed.
Redirecting to /bin/systemctl start vboxadd.service
Job for vboxadd.service failed because the control process exited with error code.
See "systemctl status vboxadd.service" and "journalctl -xe" for details.
Unmounting Virtualbox Guest Additions ISO from: /mnt
==> virtualbox: Checking for guest additions in VM...
    virtualbox: No guest additions were detected on the base box for this VM! Guest
    virtualbox: additions are required for forwarded ports, shared folders, host only
    virtualbox: networking, and more. If SSH fails on this machine, please install
    virtualbox: the guest additions and repackage the box to continue.
    virtualbox: 
    virtualbox: This is not an error message; everything may continue to work properly,
    virtualbox: in which case you may ignore this message.

The shell provisioner and vagrant ssh are still working fine, though.