Windows Server 2012 R2 Installation Options (Objective 1.1)

There are three different graphical interfaces available available for installation in Server 2012 R2. They are Server Core, Minimal Server Interface and Full GUI.
Server Core has almost zero graphical user interface and presents a basic Windows Command Prompt window when after you log in. The primary focus of Server Core is to either configure it locally using Powershell or remotely using server tools install on another server. The Server Configuration (sconfig.cmd) applet is still available to perfrom some basic admins tasks such as Networking, Remote Management and Windows Update settings.
Server CoreThe benefits of a Server Core installation are that it consumes less resources, has a smaller attack surface and requires less updates/patches.
Minimal Server Interface is a bit of middle ground between Server Core and the Full GUI. After you first log in, you get the familiar Server Manager app, you also have the ability to install and run any of the Administrative Tool MMCs, however there is no Windows Desktop, Start Menu, Internet Explorer.
Full GUI is the full Windows Server 2012 R2 desktop we are used to install that is very similar in appearence and functionality as Windows 8.1
 
Converting Between Installation Options:
If starting with a Server Core install you can run the following Powershell command to convert it to a Minimal Server Interface installation:
Install-WindowsFeature Server-Gui-Mgmt-Infra
Once you have a Minimal Server Interface installation run the following Powershell command to convert it to the Full GUI installation:
Install-WindowsFeature Server-Gui-Shell
Server-Gui-Mgmt-Infra represents the feature required for the Minimal Server Interface.   Server-Gui-Shell represents the feature required for converting to the Full GUI but it also requires the Server-Gui-Mgmt-Infra feature as well.

This process can be reversed using the remove-WindowsFeature Powershell command for example, the below Powershell command will revert a Full GUI to Server Core:
remove-WindowsFeature Server-Gui-Shell, Server-Gui-Mgmt-Infra

You can also use Server Manager to add or remove the revelvent features to switch between the different installation options:
Server Manager - GUI OptionsMuch like the Powershell commands Graphical Management Tools and Infrastructure represents the feature required for the Minimal Server Interface.Server Graphical Shell represents the feature required for converting to the Full GUI (it will install the Server-Graphical Management Tools and Infrastructure feature as well).