start a bridged vm with static ip (change if necessary). After this script runned just ssh into the machine and start the install_pihole.sh skript

Pihole Vagrantfile

# mode: ruby -*-
# vi: set ft=ruby :

# All Vagrant configuration is done below. The "2" in Vagrant.configure
# configures the configuration version (we support older styles for
# backwards compatibility). Please don't change it unless you know what
#0#R0're doing.
Vagrant.configure("2") do |config|
  # The most common configuration options are documented and commented below.
  # For a complete reference, please see the online documentation at
  # https://docs.vagrantup.com.

  # Every Vagrant development environment requires a box. You can search for
  # boxes at https://vagrantcloud.com/search.
  config.vm.box = "ubuntu/bionic64"
    # Bridged network with fixed ip on *.23!
  config.vm.network "public_network"#, ip: "192.168.XXX.XXX" #insert static ip for the vm & dont forget to use these while installing pihole
  config.vm.hostname = "pihole" #should be available as pihole hostname
  # Share an additional folder to the guest VM. The first argument is
  # the path on the host to the actual folder. The second argument is
  # the path on the guest to mount the folder. And the optional third
  # argument is a set of non-required options.
  # config.vm.synced_folder "../data", "/vagrant_data"

  # Provider-specific configuration so you can fine-tune various
  # backing providers for Vagrant. These expose provider-specific options.
  # Example for VirtualBox:
  #
  config.vm.provider "virtualbox" do |vb|
  #   # Display the VirtualBox GUI when booting the machine
  #   vb.gui = true
  #
  #   # Customize the amount of memory on the VM:
    vb.memory = "512"
  end
  #
  # View the documentation for the provider you are using for more
  # information on available options.

  # Enable provisioning with a shell script. Additional provisioners such as
  # Puppet, Chef, Ansible, Salt, and Docker are also available. Please see the
  # documentation for more information about their specific syntax and use.
  config.vm.provision "shell", inline: <<-SHELL
    apt-get update
    # disable and stop default dns settings
    service systemd-resolv stop
    systemctl disable systemd-resolv
    mv /etc/resolv.conf /home/vagrant/resolv.conf.bak #just a backup for any case
    echo "curl -sSL https://install.pi-hole.net | bash" > install_pihole.sh
  SHELL
end