Over the past several years that I have been instructing Windows classes, I have had a lot of raised eye brows when it comes to the topic of Server Core. Although my classes agrees with the principals of smaller attack foot print and less management, the whole text based interface do not settle well. With the release of Server Core 2008 R2, we were given the sconfig tool to help make configuration of the server core a bit easier. It also made it easier to configure the firewall to allow the core to be managed from a GUI machine.
With Windows Server 2012, we have another option. We can install either Server Core or the Full installation and simply switch between the two of them. The GUI is now an installable feature that can also be removed. This will result in a reboot when making the switch and some delay while Windows reboots. In this scenario, you can run Server Core for daily operations. If you need to do some work that you would rather do in a GUI, you can add the GUI feature. Once you have finished with the GUI, remove the GUI feature and reboot.
Here is the process to convert from a GUI to Server Core.
Log in to Server 2012 as an Administrator.
In Server Manager, click Manage –> Remove Roles and Features
On the Before you Begin window, click Next.
Select the server that you want to change to a server core and click Next.
At the Remove servers roles window, click Next.
On the Remove Features window, clear the User Interfaces and Infrastructure check box and click Next.
Check the Restart the destination server automatically if required check box if you want to implement this change immediately.
Click Yes and then Next.
At the confirmation screen, you may have noticed that other roles and features are also removed. For example, Windows Deployment Server cannot be installed on a Server Core. If you have WDS installed on this GUI installation, it will be removed if your switch to the core installation.
During the shutdown and boot up, you will have to wait for the configuration changes to be made.
Once the reboot completed, you will be in Server Core implementation. So, what do you do if you need the GUI back?
Type PowerShell and press Enter.
Type Add-WindowsFeature server-gui-shell and press Enter.
Next you need to reboot the server. Type Shutdown –t 0 –r and press Enter.
This process will cause down time of several minutes for the server. Also, remember that it may remove functionality from the server when converting to server core if that functionality is only available in the GUI installation.