create VNC server on ubuntu
sudo apt install xfce4 xfce4-goodies
sudo apt install tightvncserver
vncserver -kill :1
# setup vnc initial config
vim ~/.vnc/xstartup
# add
gnome-panel &
gnome-settings-daemon &
metacity &
nautilus &
# continue installation
sudo apt install -y gnome-panel gnome-settings-daemon metacity nautilus
cat << EOF > ~/.vnc/xstartup
#!/bin/bash
xrdb $HOME/.Xresources
startxfce4 &
EOF
chmod +x ~/.vnc/xstartup
vncserver -kill :1
vncserver -localhost
sudo apt install virtualbox
# install ext pack
sudo VBoxManage extpack install Oracle_VM_VirtualBox_Extension_Pack-6.1.38-153438.vbox-extpack