VirtualBox

VirtualBox is Sun Oracle’s desktop virtualisation software package.

Networking

Virtual machines can run in various network modes:

To set up the common use case of an Ubuntu virtual machine with a LAMP configuration:

1. In the virtual machine’s settings, use a single Adapter, and set it as Bridged Adapter, bridged to the host machine’s network interface.
2. Restart the guest OS.
3. Update the /etc/hosts file on the host machine (if required).

Management

• Disk images (.vdi) have a unique UUID which means that the same image cannot be used twice
• To clone disk images, use the syntax: vboxmanage clonehd [source-vdi] [dest-vdi] --format VDI

File sharing

Use the Shared Folders feature to share a folder with the guest:

1. In the guest, type id to get the ID of the current user.
2. Mount the drive with mount -t vboxsf -o uid=12345,gid=12345 name-of-vbox-share ~/path/to/mount
3. Unmount using umount ~/path/to/mount

Using SSH with port forwarding

If on a NAT network, set up port forwarding (port 3022 to 22 on the guest):

$ VBoxManage modifyvm CentOS-6.5-i386-minimal --natpf1 delete ssh
$ VBoxManage modifyvm CentOS-6.5-i386-minimal --natpf1 delete http
$ VBoxManage modifyvm CentOS-6.5-i386-minimal --natpf1 "ssh,tcp,,3022,,22"
$ VBoxManage modifyvm CentOS-6.5-i386-minimal --natpf1 "http,tcp,,8080,,80"

Then you can SSH from the Host to the Guest using ssh -p 3022 root@127.0.0.1

Using VirtualBox to create a Linux VM with a graphical desktop

We’ll install a desktop environment, use a VNC server to bootstrap the desktop environment, and then connect to it.

1. First initialise a Debian VM in VirtualBox:

   mkdir -p ~/vms/debian && cd ~/vms/debian
   
   cat <<EOF > Vagrantfile
   Vagrant.configure("2") do |config|
   config.vm.box = "debian/bullseye64"
   config.vm.network "private_network", type: "dhcp"
   end
   EOF
   
   vagrant up
   
   vagrant ssh
   

2. Install a desktop environment:

   1. To use Xfce:

      • Display manager: lightdm
      • Desktop environment: xfce4
      • Display server/protocol: xorg

      sudo apt-get update
      sudo apt-get install -y xorg xfce4 xfce4-goodies
      

   2. To use GNOME:

      • Display manager: gdm3
      • Desktop environment: gnome
      • Display server/protocol: xorg

      sudo apt-get update
      sudo apt-get install -y xorg gnome gnome-shell
      

3. Install a VNC server and start it:

   sudo apt install -y tightvncserver
   
   vncserver :1 -geometry 1920x1080
   

   You’ll be prompted for a password. Enter one, and then confirm it.

4. On the host workstation, connect to the desktop (here’s an example using Fedora because that’s my host OS):

   sudo dnf install tigervnc
   
   # Show the IP address for eth1
   vagrant ssh -c 'ip addr show eth1' | grep 'inet ' | awk '{print $2}' | cut -d/ -f1
   # e.g. 192.168.56.3
   
   vncviewer 192.168.56.3::5901
   

5. When finished, terminate the VNC server in the guest VM:

   vncserver -kill :1
   

☃

Useful hints

• At any time you can see the default display manager that will be used (e.g.lightdm):

    $ cat /etc/X11/default-display-manager
    /usr/sbin/lightdm
  

• In Debian: Create a new user account (for logging in to the box):

    sudo adduser --gecos "" tom
    sudo usermod -aG sudo tom
  

Troubleshooting