In Windows Server 2012, an installation of Server with a GUI needs 11 GB of disk space (excluding page file). In Windows Server 2012 R2, that same installation needs just 9.8 GB of space to achieve the same exact level of installation (in terms of the roles and features available on disk). Similarly, we've reduced the footprint of Server Core from 6 GB to 5.2 GB! The decrease in disk space requirements means you can fit more Windows Server 2012 R2 Server Core VHDs on a storage volume of the same size than you could with Windows Server 2012.

A significant chunk of disk space is occupied by features that are available for installation but aren't installed. As you install updates on a server, the footprint continues to grow. Some security scanning tools may warn that unpatched files exist within the c:\windows\winsxs directory. In fact, these are not security vulnerabilities. Rather, they are archived versions of updated system files that may be restored in the event you choose to uninstall an update.

Microsoft has invested significantly in update technology, and we offer ultimate flexibility in terms of installing updates. Consider:

1. Updates can be installed in any order
2. You can uninstall any update in any order, even if that order is different from the order in which you installed the updates in the first place
3. We support sophisticated error detection and recovery to protect the component store from installation failures

However, this flexibility results in an increase in disk usage.

Introducing Component Cleanup

To reduce the impact of this flexibility, in Windows Server 2012 R2, we are introducing Component Cleanup, which enables administrators to further reduce the disk footprint of their servers while leaving feature installation unaffected. Here's what Component Cleanup does:

1. Compresses all manifest files, so that they take up less disk space
2. Compresses inactive payloads (i.e. uninstallation data for hotfixes)

Component Cleanup takes about 45 minutes to run on our average test hardware and results in a further 1.2 GB savings on a Server with a GUI disk image. It doesn't make features unavailable for installation and it doesn't require computers to have a network connection at all. All compression is done locally and then any decompression, if needed, is done on demand. You can run Component Cleanup by using dism.exe:

Dism /Online /Cleanup-Image /StartComponentCleanup

More information is available in our TechEd presentation which was presented in New Orleans on June 3, 2013.  We also presented this content at TechEd in Madrid, Spain on June 25. A link to the recording is available here: https://channel9.msdn.com/Events/TechEd/Europe/2013/MDC-B339#fbid=GgZkc8YUgzu

Quick Trick: Remove Disabled Feature Payloads using Features on Demand

In Windows Server 2012, we introduced Features on Demand which enables administrators to remove the file payloads of unneeded features from their Windows Servers, thereby reducing the needed disk space significantly. You can set up a Windows Server however you like and then remove the payloads for any roles that aren't enabled by running just two PowerShell commands:

1. $L = Get-WindowsFeature | Where InstallState -EQ Disabled
2. Uninstall-WindowsFeature $L -Remove

Here's what each line does:

1. first, get the list of features that aren't installed but have payloads present on disk
2. remove the payloads from that list

Once a feature's payload is removed in this way, the features files and any patches related to it are removed from the local disk. As a result, the feature can't be installed without an external, remote source. By default, Windows can download missing or corrupt features from Windows Update. The path to a Windows image that contains the desired features can also be specified on the command line. For example:

PS> Install-WindowsFeature –FeatureName Server-Gui-Shell –Source wim:x:\sources\install.wim:4

(x:\sources\install.wim is the path to the install.wim file on a retail Windows Server DVD-ROM or mounted ISO)

Another way is by checking for the installation state of various Windows features and modifying your application's behavior accordingly. We make this possible through the public Dism APIs.

Here is some sample C++ code. It won't compile straight away, but reading over this code snippet should give you an idea about how you can check for Server Core.

What the code does

The code calls the Dism API to check the installation state of a Windows feature.

How to use it

1. Determine which functionalities of your app are not available in Server Core. Features that are not available in Server Core include MMC, Internet Explorer, MSHTML, and many GUI libraries such as HTML Help and WPF. Locate the FeatureNames of those features by calling dism /online /get-features from a command prompt.
2. Complete the TODO: block with your own logic that should execute when the features you selected in the previous step are not installed.
3. Optionally, add additional cases to check for the other installation states. The code checks only for "Disabled with Payload Removed" state. Other states are discussed on the MSDN documentation (link below).

Code sample

HRESULT CheckFeatureState(_featureName){

    // Call to get feature info from Dism API:

    hr = DismGetFeatureInfo(session, _featureName,NULL, DismPackageNone,&featureInfo);

    if(S_OK != hr){

        Log::Error(L"DismGetFeatureInfo failed with error code: %d")

        return hr;

    }

    if(featureInfo->FeatureState!= DismStateRemoved) {           

        // Feature is "Disabled with payload removed"

        // TODO: Adapt app logic here or return appropriate value

    }                                                                 

    hr = DismDelete(featureInfo);  // free memory allocated by DismGetFeatureInfo.

    if(S_OK != hr){

        Log::Error(L"DismDelete failed with error code: %d");

        return hr;

    }

    featureInfo =NULL;

    return hr; 

} 

You can read more about the Dism API on MSDN: https://msdn.microsoft.com/library/windows/desktop/hh824738.aspx

Thanks for supporting Server Core through your development efforts!

The Server Core Team

If you later want to reinstall one of these features, Windows needs to use a remote installation source because, of course, the files aren’t available (“staged”) on the local disk.By default, we use Windows Update as an installation source. However, not all servers have connectivity or access to Windows Update. If you don’t have connectivity to Windows Update, you need to supply an installation source, e.g.

[PowerShell]
Install-WindowsFeature Server-Gui-Shell -Source wim:d:\sources\install.wim:4

Note: WSUS is not supported as an installation source.

Let’s see how this breaks down:

First, the -Source flag tells Windows to use a specified source. You can specify a directory to a winsxs folder e.g. on a mapped network drive, mounted WIM or VHD, or local disk. You can also specify the path to a Windows Image (WIM) file directly, by using the wim: prefix and specifying the image index immediately after the filename, in this case :4 for Serverdatacenter. (If you are running Standard edition, :2 will give you the full Standard image).For completeness, the default image indices are as follows:

(e.g. dism.exe /get-wiminfo /wimfile:d:\sources\install.wim )

Index : 1

Name : Windows Server 2012 SERVERSTANDARDCORE

Description : Windows Server 2012 SERVERSTANDARDCORE

Size : 7,195,580,708 bytes

Index : 2

Name : Windows Server 2012 SERVERSTANDARD

Description : Windows Server 2012 SERVERSTANDARD

Size : 11,999,848,937 bytes

Index : 3

Name : Windows Server 2012 SERVERDATACENTERCORE

Description : Windows Server 2012 SERVERDATACENTERCORE

Size : 7,176,243,455 bytes

Index : 4

Name : Windows Server 2012 SERVERDATACENTER

Description : Windows Server 2012 SERVERDATACENTER

Size : 11,995,224,677 bytes

These correspond to:

1.        Standard Core (with optional GUI features removed)
2.        Standard (all features except .NET 3.5. present)
3.        Datacenter Core (optional GUI features removed)
4.        Datacenter (all features except .NET 3.5. present)

You can also use the path to a WinSxS folder as a -Source. If you mount the install.wim file from the Windows Setup media, you’ll find the WinSxS folder as a sub-folder of the Windows folder.

If you are using a source that is located on a network share, you might see an error message that resembles the following:

Install-WindowsFeature Server-Gui-Shell -Source:wim:z:\install.wim:2

Install-WindowsFeature : The request to add or remove features on the specified server failed.

Installation of one or more roles, role services, or features failed.

The source files could not be downloaded.

Use the "source" option to specify the location of the files that are required to restore the feature. For more information on specifying a source location,

seehttps://go.microsoft.com/fwlink/?LinkId=243077. Error: 0x800f0906

At line:1 char:1

+ Install-WindowsFeature Server-Gui-Mgmt-Infra,Server-Gui-Shell -Source:wim:z:\ins ...

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : InvalidOperation: (@{Vhd=; Credent...Name=localhost}:PSObject) [Install-WindowsFeature], Exception

    + FullyQualifiedErrorId : DISMAPI_Error__Cbs_Download_Failure,Microsoft.Windows.ServerManager.Commands.AddWindowsFeatureCommand

Success Restart Needed Exit Code      Feature Result

------- -------------- ---------      --------------

False   No             Failed         {}

Example: Installing Server-Gui-Shell (Server Graphical Shell) on a Windows Server 2012 Standard box.

That’s because Install-WindowsFeature uses the machine account credentials – not your local user account credentials – to access the installation source. If the installation source is located on a network share, ensure that the machine account has permissions to read from the network share.

If you were to install an optional feature immediately after installing Windows Server 2012, you would have the RTM version of the binaries both installed on your server and on your installation media source. That’s all well and good. However, let’s say you update your server using Windows Update and an old version of a feature is superseded. Later, you want to reinstall that updated feature but the binaries have been removed from your system. When Windows goes to look at your installation source, it won’t be able to find the files for the feature anymore because it is looking for the updated binaries. Therefore, you need to patch your installation source as well.

My colleague Joseph Conway has written a post about how to actually go about updating your Windows images (your installation sources) using patches from the Microsoft Update Catalog. Read more here: https://blogs.technet.com/b/joscon/archive/2012/11/14/how-to-update-local-source-media-to-add-roles-and-features.aspx

It is important to note that when you update your installation source, you are adding additional versions to the component store. Old versions of components remain available for servers that need those versions. However, when you install a Windows feature using Install-WindowsFeature, Windows kicks off a Windows Update scan immediately after installing the feature. This ensures that (at least for servers with Windows Update enabled), accidentally installing an old version of a feature won’t compromise the security of the system.

Please let me know if you have any issues using the new Features on Demand functionality. We’d love to hear our customers’ feedback and I look forward to answering any questions that you may have.

1. Server Core – always installed and enabled; the baseline feature for all Windows Servers
2. Server Graphical Management Tools & Infrastructure – functionality for Minimal Server Interface
3. Server Graphical Shell – equivalent to Server with a GUI

We also promised to explain how to combine these features in order to minimize your server’s surface area while preserving just enough of the functionality you need; and indeed, that’s our topic today.
There are two ways to configure the Minimal Server Interface: either start with Server with a GUI and uninstall the Server Graphical Shell feature, or start with Server Core and install the Server Graphical Management Tools & Infrastructure feature.

What is affected when I uninstall the Server Graphical Shell?

In some cases, when you uninstall the Server Graphical Shell, Windows features that depend on Server Graphical Shell will also be uninstalled. In Server Manager, a pop-up dialog box will warn you about what will be uninstalled. Non-Windows features, such as third-party software and other Microsoft products that don’t ship as part of Windows Server 2012, are not affected by the Install-WindowsFeature and Uninstall-WindowsFeature cmdlets. If you aren’t sure what an installation or uninstallation action is going to affect, you can add the -WhatIf flag to see what will be installed or uninstalled along with your selection.

Uninstall-WindowsFeature Server-Gui-Shell -WhatIf

Settings associated with uninstalled features are also removed in some cases. You should back up any settings associated with a feature before you uninstall that feature.

Installing Minimal Server Interface

Because the Minimal Server Interface is situated between the Server Core and Server with a GUI modes, you can either install features on Server Core or remove features from Server with a GUI to reach the Minimal Server Interface installation state.

Caveat: Features on Demand. When you start with a Server Core installation, the files needed to install graphical features aren't installed on the local disk. This is actually a feature called remotification which involves removing the binaries from the local disk while preserving metadata to allow the binaries to be securely reintroduced at a later date. When you try to install a GUI feature, the necessary files are downloaded from Windows Update using a feature called Features on Demand. An internet connection is required and several gigabytes of data will be downloaded. If you don’t want to download all this data, or if your server doesn’t have an internet connection, you can supply an alternate installation source on the command line or configure one via Group Policy. For more information, see the Using Windows Server “8” Installation Options document on technet. 

• To install Server Graphical Management Tools & Infrasturctureon Server Core:
  1. Open PowerShell, then run the following command: Install-WindowsFeature Server-Gui-Mgmt-Infra
  2. Restart the server when prompted (or run Restart-Computer in PowerShell)

• To remove Server Graphical Shellon Server with a GUI (either locally or remotely) using Windows PowerShell:
  1. Open PowerShell, then run the following command: Uninstall-WindowsFeature Server-Gui-Shell -WhatIf
  2. You should see Collecting data... for a few moments, and then a listing of the installation summary will be displayed in the PowerShell window. This summary lists any other features that will also be uninstalled at this time.

     PS C:\> Uninstall-WindowsFeature Server-Gui-Shell -WhatIf
     What if: Checking if running in 'WhatIf' Mode.
     What if: Performing uninstallation for "[User Interfaces and Infrastructure] Server Graphical Shell".
     What if: This server may need to be restarted after the removal completes.
                
     Success Restart Needed Exit Code      Feature Result
     ------- -------------- ---------      --------------
     True    Maybe          Success        {Server Graphical Shell}

  3. Restart the server when prompted (or run Restart-Computer in PowerShell)

You can also use the Server Manager GUI remotely to install or uninstall Windows features, including “User Interfaces and Infrastructure,” from a Windows 8 “client” PC or another Windows Server 2012 server that already has Server Manager installed. In other words, you can use Server Manager remotely to manage a server running in Server Core mode.

1. Open Server Manager, click Manage, then Remove Roles and Features.
2. On the Server Selection page, select the local server (and/or any servers you want to manage) and click Next.
3. On the Features page, expand User Interfaces and Infrastructure and uncheck Server Graphical Shell. Make sure that Graphical Management Tools and Infrastructure remains checked; unchecking that feature will uninstall Minimal Server Interface as well, resulting in a Server Core Installation.
4. At this point, Server Manager will warn you of the impending removal of any dependent features -- such as Desktop Experience -- that you didn't explicitly select to remove. If you don't see a warning, then no additional Windows features will be affected. Accept
5. Restart the server when prompted.

After you restart the server, Windows will be configured with the Minimal Server Interface. Here’s what it will looks like after you log in:

Figure 1. The Minimal Server Interface after signing in

You’ll see Server Manager, which is a graphical tool you can use to manage the local server and other remote servers. Behind Server Manager (which starts maximized on most configurations) you’ll find a command prompt, which you can use to start other applications and management tools (such as “servermanager” if you close Server Manager, or even “powershell” to get a Windows PowerShell command line environment).

If you close everything, you’ll be left with a black screen. To get back to a command line environment or Server Manager, press CTRL+ALT+DEL and select Task Manager. From there, click More details, then File>Run New Task. Type the command you want to run (such as “cmd” to get your command prompt back) and click OK or press Enter.

Next Steps

Now that you have installed the Minimal Server Interface, you can use the command line to install software products (using msiexec or the product’s setup.exe), Windows features, and server roles. You can also use the local management tools provided by Server Manager. On the Tools menu, you’ll find quick shortcuts to most of your MMC snap-ins. Server Manager can also be used to manage other servers, including servers that don’t have Server Manager installed (such as those running in Server Core mode). You can “Add other servers to manage” and then right-click on servers in the list view to see what management options are available for that particular server. Here are some examples of things you can do:

• Launch Disk Management to remotely configure hard disk partitions
• Manage Remote Desktop scenarios and licensing (RDSH)
• Configure Failover Clusters
• Open MMC snap-ins
• Open a remote PowerShell session

In some cases, you can even manage multiple servers simultaneously, from the same interface. Server Manager is a very powerful tool indeed. It is important to note, however, that all functionality exposed through Server Manager is also available via Windows PowerShell both locally and remotely. 

It's also a great idea to start exploring PowerShell to experience the power and control that our new command line interfaces offer. You can manage this server remotely, too, from other Windows 8 PCs and servers. We'll be posting some general information on remote management in an upcoming post; for now, check out What needs to be configured to do remote disk management of a Server Core installation in Windows Server 2012 PowerShell at the Server and Cloud Partner and Customer Solutions Team Blog.

Conclusion

The Minimal Server Interface is designed to be a compatibility or transitional layer from a Server with GUI to Server Core. Although you benefit from reduced patching footprint and lower resource utilization in comparison to the full Server with a GUI installation option, the smallest surface area is achieved using Server Core. When you are unable to use Windows Server Core, the Minimal Server Interface provides the best of both worlds of Windows Server. It delivers comprehensive graphical management capabilities while reducing patching requirements and minimizing disk and memory footprint. Please try the Minimal Server Interface and let us know what you think!

About this Video

Principal Group Program Manager Andrew Mason and Program Manager Ben Herila join us for today’s show as we go over the latest features found in Windows Server “8” Beta – Server Core. Tune in as we cover improvements made to service and manageability, role support and flexibility, and the various configuration levels.

Here is a direct link to the episode.

Engineering Goals

Windows applications and server roles have traditionally been built on top of what is known as the Windows Foundation: a monolithic package containing dependencies for all of Windows. Since Windows Server 2008, we have been working to break this package up into smaller, installable features. The diagram below shows how the Windows Foundation is split up in Windows Server 2012:

While the Windows Foundation feature is always installed on “client” editions of Windows 8, it is possible to install only the Server Core feature on Windows Server. This is the recommended and default installation mode for Windows Server 2012. The all-new Minimal Server Interface, which is comprised of the yellow highlighted packages in the diagram above, installs on top of Server Core. It is designed to serve as a compatibility layer for those applications that do not yet work on Server Core.

Why is Minimal Server Interface Important?

Before we explain why the Minimal Server Interface itself is important, we will first explain why Server Core is important. Minimizing the disk space and memory requirements for Windows Server enables users to increase the density of their servers (especially when virtual machines are involved) and scale out their deployments significantly. With Server Core, we not only accomplish considerable space savings (thereby reducing storage costs), but we also minimize the attack surface area (thereby increasing security and reliability). Reducing the overall footprint of Windows also enables us to minimize the servicing footprint. By limiting the number of components that must be patched on a given server, we are able to naturally minimize the number of applicable patches, thereby reducing the frequency of reboots and increasing server availability. Windows Server 2012’s focus on being a great platform for private cloud deployments further underscores the importance of our efforts to enable a minimal system footprint.

As you might imagine, Server Core represents quite a scaled-down version of Windows Server. We eliminated many GUI features, which are some of the most bulky packages in Windows. However, we realized that many users are not yet ready to move to a remotely managed and local command-line-only Windows Server. For this reason, we created the Minimal Server Interface, which is an intermediate state in between Server with a GUI and Server Core. Practically, the Minimal Server Interface contains almost everything that Server with a GUI has, with two notable exceptions. Internet Explorer 10 and the Windows Explorer shell are not installed in the Minimal Server Interface. However, Server Manager, MMC, and a number of graphical management options are available for use. Accordingly, the Minimal Server Interface provides comprehensive local GUI management capability without the attack and servicing footprint of a full “Server with a  GUI” installation. 

Configuring Minimal Server Interface

The Minimal Server Interface is designed to be a state in between Server with a GUI and Server Core. As it is intended primarily as a transitional layer, it is not directly exposed in the Windows Server installation options dialog box. You’ll need to install the Minimal Server Interface on top of Server Core, or remove the Server Graphical Shell from a Server with a GUI installation. The Minimal Server Interface works this way because there are three particular Windows features (among others, of course) that can be installed on any server running Windows Server 2012:

1. Server Core – always installed and enabled; the baseline feature for all Windows Servers
2. Server Graphical Management Tools & Infrastructure – functionality for Minimal Server Interface
3. Server Graphical Shell – equivalent to Server with a GUI

In our next blog post, we will describe how to configure the Minimal Server Interface in two ways: one, for administrators who choose to start with the default option of Server Core and want additional GUI functionality, and the other, for administrators who are currently using the Server Graphical Shell and want to reap some of the benefits of a minimal system footprint.

Until next time,

Ben Herila
Program Manager, Windows Server

Today I’m going to start by discussing some of the ways you can take advantage of the ability to move between Server Core and Server with a GUI in Windows Server 2012.

Changing server requirements – If you have deployed Server Core and then there is a change in what needs to run on the server that requires either Minimal Server Interface or Server with a GUI you can now convert up without having to reinstall and rebuild the server.

Troubleshooting or configuration – If there are any issues that you need to trouble shoot or configuration changes you want to make and find it easier to do either with the local GUI tools, you can convert to either Minimal Server Interface or Server with a GUI.

Initial configuration – You can install Server with a GUI, configure the server as desired for your environment, and then convert to Server Core for production and get all the servicing and reboot reduction benefits of Server Core.

Single master image – With the ability to switch between Server Core and Server with a GUI you can create a single master image for deployment. Once installed on a new server it can then be converted to Server Core if that is the planned  configuration for the server. There is no longer a need to create and maintain two Windows Server images.

For steps on how to convert between Server Core and Server with a GUI, see the Installation Options topic for the beta release: https://technet.microsoft.com/en-us/library/hh831786.aspx We’ll cover the ways to convert in more detail in a future posting, as well as Minimal Server Interface, and Features on Demand.

More details will be posted here in the coming weeks....

Stay tuned to the Server Core blog for more details on Server Core and the, Minimal Server Interface.