New and flexible ways to make changes of a Windows Server 2012 installation after the fact are available. And IT pros can now convert a server from and to Server Core, and change the availability of server components that are previously committed at an installation time. This introduces new dynamics and exciting scenarios for improving supportability, efficiency, and security. This article highlights the three available installation options and some key operations based on the Release Candidate, Build 8400. There is additional information of Windows Server 2012 including: a free eBook, available editions, and a reference table summarizing the available features in each installation option available elsewhere.
This is the default and preferred configuration for deploying Windows Server 2012. Server Core was introduced in Windows Server 2008 as a minimal installation option and a low-maintenance environment with limit functionality, while reducing:
- Servicing requirements
- Management requirements
- Attack surface
- Disk space usage
- Memory (RAM) usage
It is installed without graphical user interface and with only the binaries required by configured server roles.
Notice that the preference for deploying Server Core of Windows Server 2012 in an enterprise signifies a new OS standard with improved user experience and supportability while still offering the above mentioned key attributes for private cloud computing. And the growing number of Server Core instances in production also suggests even higher market demands for process automation, remote management, etc. in enterprise IT space. And for IT pros, that means PowerShell scripting, a lot of. Which is why in Windows Server 2012, PowerShell support achieves a critical mass with 2,400+ cmdlets compared to around 230 in the early days of Windows Server 2008.
Server with GUI
This installation option is the familiar one by most IT pros. It installs the user interface and all server tools. The default settings are shown in Figures 1 and 2. In Windows Server 2012, the interface although with Metro-style looks and feels, it however does not support Metro-style applications without adding Desktop Experience feature.
Figure 1. Default GUI Settings of Windows Server 2012 full Installation Shown in Server Manager
Figure 2. Default GUI Settings of Windows Server 2012 full Installation Shown in PowerShell
One important deployment feature in Windows Server 2012 is that the ability to convert from a Server with GUI deployment to a Server Core installation, and vice versa, with PowerShell. This is different from that in Windows Server 2008 release where one cannot change the installation option of a server, once installed. To convert an installation from Server with GUI to Server Core, run the following PowerShell command:
Uninstall-WindowsFeature Server-Gui-Mgmt-Infra -Restart
And the installation will take minute to reconfigure followed by rebooting into Server Core with all settings removed from User Interfaces and Infrastructure as shown in Figure 3 below:
Figure 3. Settings in Server Core of Windows Server 2012 from Removing Server-Gui-Mgmt-Infra
Notice the above converting from a Server with GUI to Server Core installation does not completely remove all the files associated from the local disk. Such that to re-install the GUI components from this state, simply run:
Install-WindowsFeature Server-Gui-Shell -Restart
This will convert this Server Core installation back to Server with GUI with settings shown in Figures 1 and 2. To completely remove all associated files and dependent components of a role or feature, use the
–Remove flag. This brings the feature to a state called “disabled with payload removed.” And to reinstall a role or feature disabled with payload removed, one will need to have an installation source and use the –Source for specifying the path. And the component sources must be from the exact same version of Windows for the reinstallation to work. Without the –Source option, PowerShell will use Windows Update by default. This ability to remove and reinstall a component of Windows Server 2012 is presented as “Features on Demand.”
Minimal Server Interface
This is new. In Windows Server 2012, with a Server with GUI installation one can remove the Server Graphical Shell (which provides full GUI for server) to set a full server installation with the so-called Minimal Server Interface option with the following PowerShell comlet.
Unstall-WindowsFeature Server-Gui-Shell -Restart
This basically provides a Server with GUI, but without installing Internet Explorer 10, Windows Explorer, the desktop, and the Start screen. Additionally, Microsoft Management Console (MMC), Server Manager, and a subset of Control Panel are still in place. Minimal Server Interface requires 4 GB more disk space than Server Core alone. Figure 4 shows the user experience of Minimal Server Interface in which the server boots with the shown settings:
Figure 4. User Experience of Minimal Server Interface of Windows Server 2012
Graphical Management Tools and Infrastructure is the set of features providing a minimal server interface for supporting GUI management tool. Uninstalling Graphical Management Tools and Infrastructure at this time will further convert the server to a Server Core installation with the settings in Figure 3.
There is an apparent inheritance relationship between Server-Gui-Mgmt-Infra and Server-Gui-Shell as illustrated in Figure 5.
Figure 5. Dependency Between Server GUI Components in Windows Server 2012