CentOS 7 Minimal kickstart file and Packer config.json for building a vagrant virtualbox base box with guest additions installed. Based off of https://www.centosblog.com/centos-7-minimal-kickstart-file/

centos7.json

{
  "builders": [{
    "type": "virtualbox-iso",
    "guest_os_type": "RedHat_64",
    "iso_url": "[YOUR ISO PATH HERE]",
    "iso_checksum": "[YOUR ISO CHECKSUM HERE]",
    "iso_checksum_type": "sha256",
    "ssh_username": "vagrant",
    "ssh_password": "vagrant",
    "ssh_wait_timeout": "1500s",
    "boot_command": [
      "<esc>",
      "<wait>linux inst.ks=hd:/dev/fd0:ks.cfg<enter>"
    ],
    "boot_wait": "5s",
    "disk_size": 100000,
    "floppy_files": [
      "ks.cfg"
    ],
    "hard_drive_interface": "sata",
    "shutdown_command": "echo 'vagrant' | sudo -S shutdown -P now",
    "vboxmanage": [
      ["modifyvm", "{{.Name}}", "--memory", "1024"]
    ]
  }],
  "provisioners": [{
    "type": "shell",
    "inline": [
      "sleep 30",
      "sudo mkdir /media/VBoxGuestAdditions",
      "sudo mount -o loop,ro /home/vagrant/VBoxGuestAdditions.iso /media/VBoxGuestAdditions",
      "sudo /bin/sh /media/VBoxGuestAdditions/VBoxLinuxAdditions.run",
      "sudo umount /media/VBoxGuestAdditions",
      "sudo rmdir /media/VBoxGuestAdditions"
    ]
  }],
  "post-processors": [{
    "type": "vagrant",
    "keep_input_artifact": true,
    "output": "centos_7_with_guestadditions.box"
  }]
}

ks.cfg

install
cdrom
cmdline
lang en_US.UTF-8
keyboard us
timezone Pacific/Honolulu
auth --useshadow --enablemd5
firewall --enabled --ssh --http
services --enabled=NetworkManager,sshd
eula --agreed
ignoredisk --only-use=sda
reboot
network --bootproto=dhcp --device=enp0s3 --onboot=on --hostname=[YOUR HOSTNAME HERE]
bootloader --location=mbr
zerombr
clearpart --all --initlabel
part swap --asprimary --fstype="swap" --size=1024
part /boot --fstype xfs --size=200
part pv.01 --size=1 --grow
volgroup rootvg01 pv.01
logvol / --fstype xfs --name=lv01 --vgname=rootvg01 --size=1 --grow
rootpw --iscrypted [PUT PASSWORD CRYPT HASH HERE]
user --name=vagrant --iscrypted --password=[PUT PASSWORD CRYPT HASH HERE]
repo --name=base --baseurl=http://mirror.cogentco.com/pub/linux/centos/7/os/x86_64/
%packages --nobase --ignoremissing
@core
epel-release
dkms
kernel-devel
kernel-headers
make
automake
gcc
gcc-c++
bzip2
%end
%post
SUDOERS_FILE=sudoers
SSHD_CONFIG=sshd_config
cp /etc/${SUDOERS_FILE}{,.bak}
(
  SUDOERS_FILE=sudoers
  sed 's/^Defaults[[:space:]]\+requiretty/Defaults  !requiretty/' /etc/${SUDOERS_FILE} > /tmp/${SUDOERS_FILE}
  mv /tmp/${SUDOERS_FILE} /etc/${SUDOERS_FILE}
  sed 's/^Defaults[[:space:]]\+!visiblepw/Defaults   visiblepw/' /etc/${SUDOERS_FILE} > /tmp/${SUDOERS_FILE}
  mv /tmp/${SUDOERS_FILE} /etc/${SUDOERS_FILE}
)
chown root:root /etc/${SUDOERS_FILE}
chmod 0660 /etc/${SUDOERS_FILE}
echo "vagrant ALL = (ALL)  NOPASSWD: ALL" >> /etc/${SUDOERS_FILE}
(
  mkdir /home/vagrant/.ssh
  chmod 0700 /home/vagrant/.ssh
  cd /home/vagrant/.ssh
  echo "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA6NF8iallvQVp22WDkTkyrtvp9eWW6A8YVr+kz4TjGYe7gHzIw+niNltGEFHzD8+v1I2YJ6oXevct1YeS0o9HZyN1Q9qgCgzUFtdOKLv6IedplqoPkcmF0aYet2PkEDo3MlTBckFXPITAMzF8dJSIFo9D8HfdOV0IAdx4O7PtixWKn5y2hMNG0zQPyUecp4pzC6kivAIhyfHilFR61RGL+GPXQ2MWZWFYbAGjyiYJnAmCP3NOTd0jMZEnDkbUvxhMmBYSdETk1rRgm+R4LOzFUGaHqHDLKLX+FIPKcF96hrucXzcWyLbIbEgE98OHlnVYCzRdK8jlqm8tehUc9c9WhQ== vagrant insecure public key" > authorized_keys
  chmod 0600 authorized_keys
  chown vagrant:vagrant authorized_keys
  cd /home/vagrant
  chown vagrant:vagrant /home/vagrant/.ssh
)
(
  SSHD_CONFIG=sshd_config
  sed 's/^[[:space:]]*#*UseDNS[[:space:]]\+yes/UseDNS no/' /etc/ssh/${SSHD_CONFIG} > /tmp/${SSHD_CONFIG}
  mv /tmp${SSHD_CONFIG} /etc/ssh/${SSHD_CONFIG}
)
chown root:root /etc/ssh/${SSHD_CONFIG}
chmod 0600 /etc/ssh/${SSHD_CONFIG}
%end

Hey dude, I'm having an issue with the boot command portion of this.

"linux inst.ks=hd:/dev/fd0:ks.cfg"

Watching the VM I see it type those commands and starts running, but I still wind up on the Centos GUI installation screen.

I think the issue is something to do with the path, but I can't figure it out. I've tried:
inst.ks=hd:/dev/fd0:ks.cfg
inst.ks=hd:fd0:ks.cfg
inst.ks=hd:fd0:/ks.cfg

Any idea how to figure out what's going on??

Hey dude, I'm having an issue with the boot command portion of this.

"linux inst.ks=hd:/dev/fd0:ks.cfg"

Watching the VM I see it type those commands and starts running, but I still wind up on the Centos GUI installation screen.

I think the issue is something to do with the path, but I can't figure it out. I've tried:
inst.ks=hd:/dev/fd0:ks.cfg
inst.ks=hd:fd0:ks.cfg
inst.ks=hd:fd0:/ks.cfg

Any idea how to figure out what's going on??

Add the line "text" in the kickstart config file that should solve the problem. If you want to avoid X then add skipx

I switched it from .cfg to .ks for centos7

inst.ks=hd:fd0:/kickstart.ks