Headless VirtualBox

Running a VirtualBox server without a monitor or keyboard attached to it.

Creating a VM
http://www.virtualbox.org/manual/ch07.html#id2533145
Create the initial VM:

VBoxManage createvm --name "<VM Name>" --ostype "Linux" --register

CentOS 6.2 required PAE to be on:

VBoxManage modifyvm "<VM Name> --pae on

Adjust the NIC configuration - second command lets you set a custom MAC address to for the network interface:

VBoxManage modifyvm "<VM Name>" --nic1 bridged --bridgeadapter1 enp8s0f0
VBoxManage modifyvm "<VM Name> --macaddress1 080027268E94

Adjust the amount of RAM:

VBoxManage modifyvm "<VM Name>" --memory 512

Remove the audio:

VBoxManage modifyvm "<VM Name>" --audio none

Hard Disk

Add an IDE controller for the hard disk:

VBoxManage storagectl "<VM Name>" --name "IDE Controller" --add ide --controller PIIX4
Create a drive, 5GB in this example:

VBoxManage createvdi -filename ~/.VirtualBox/HardDisks/<diskname>.vdi -size 5000 -register
Add the drive to the VM:

VBoxManage modifyvm "<VM Name>" --hda "<diskname>.vdi"

or

VBoxManage storageattach "<VM Name>" --storagectl "IDE Controller" --port 0 --device 0 \ --type hdd --medium ~/.VirtualBox/HardDisks/<diskname>.vdi

Detach a drive:

VBoxManage storageattach "<VM Name>" --storagectl "IDE Controller" --port 0 --device 0 \ --type hdd --medium none

Running a VM "headless"

Starting a headless VM:

VBoxHeadless --startvm <vmname> &
Stopping a headless VM:

VBoxManage controlvm <vmname> pause|resume|reset|poweroff|savestate

Boot DVD
Register the DVD ISO file:

VBoxManage registerimage dvd /extra/CentOS-6.2-i386-minimal.iso

VBoxManage storageattach  "<VM Name>" --storagectl "IDE Controller" --port 1 --device 0 \
--type dvddrive --medium /extra/CentOS-6.2-i386-minimal.iso

Clone a VM

VBoxManage clonehd <vmname> <outputfile>

Remote Display (VRDP)
Specify a port for VRDP access, and then turn it on:

VBoxManage modifyvm "<VM Name>" --vrdeport <port number>
VBoxManage modifyvm "<VM Name>" --vrde on

Links
Secrets for controlling VirtualBox from the command line

Recent Updates

SquidGuard

SquidGuard is a URL redirector used to use blacklists with the proxysoftware Squid. There are two big advantages to squidguard: it is fast and it is free.
NCurses Disk Usage

A disk usage analyzer with an ncurses interface, aimed to be run on a remote server where you don't have an entire gaphical setup, but have to do with a simple SSH connection. ncdu aims to be fast, simple and easy to use, and should be able to run in any minimal POSIX-like environment with ncurses installed.
WPKG

WPKG is an automated software deployment, upgrade and removal program for Windows.

It can be used to push/pull software packages, such as Service Packs, hotfixes, or program installations from a central server (for example, Samba or Active Directory) to a number of workstations.

It can run as a service to install software in the background (silent install), without user interaction.

It can install MSI, InstallShield, PackagefortheWeb, Inno Setup, Nullsoft, other software installers or .exe packages, .bat and .cmd scripts and similar: no more repackaging to perform software installation.

WPKG is open source software.
opsi

opsi (Open PC Server Integration) the Open Source client management system
Vagrant

Vagrant is a tool for building complete development environments. With an easy-to-use workflow and focus on automation, Vagrant lowers development environment setup time, increases development/production parity, and makes the "works on my machine" excuse a relic of the past.