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Use the EC2Config service to perform tasks during EC2 legacy Windows operating system instance launch - Amazon Elastic Compute Cloud
EC2Config and AWS Systems ManagerEC2Config tasksEC2Config settings files

Use the EC2Config service to perform tasks during EC2 legacy Windows operating system instance launch

Note

EC2Config has reached the end of support. The operating system versions that it runs on are no longer supported by Microsoft. We strongly recommend that you upgrade to the latest launch agent.

The latest launch agent for Windows Server 2022 and later operating system versions is EC2Launch v2, which replaces both EC2Config and EC2Launch, and comes pre-installed on AWS Windows Server 2022 and 2025 AMIs. You can also manually install and configure the agent on Windows Server 2016 and 2019. For more information, see Install EC2Launch v2.

Windows AMIs for Windows Server versions prior to Windows Server 2016 include an optional service, the EC2Config service (EC2Config.exe). EC2Config starts when the instance boots and performs tasks during startup and each time you stop or start the instance. EC2Config can also perform tasks on demand. Some of these tasks are automatically enabled, while others must be enabled manually. Although optional, this service provides access to advanced features that aren't otherwise available. This service runs in the LocalSystem account.

The EC2Config service runs Sysprep, a Microsoft tool that enables you to create a customized Windows AMI that can be reused. When EC2Config calls Sysprep, it uses the files in %ProgramFiles%\Amazon\EC2ConfigService\Settings to determine which operations to perform. You can edit these files indirectly using the EC2 Service Properties system dialog, or directly using an XML editor or a text editor. However, there are some advanced settings that aren't available in the Ec2 Service Properties system dialog, so you must edit those entries directly.

If you create an AMI from an instance after updating its settings, the new settings are applied to any instance that's launched from the new AMI. For information about creating an AMI, see Create an Amazon EBS-backed AMI.

EC2Config uses settings files to control its operation. You can update these settings files using either a graphical tool or by directly editing XML files. The service binaries and additional files are contained in the %ProgramFiles%\Amazon\EC2ConfigService directory.

Contents

EC2Config and AWS Systems Manager

The EC2Config service processes Systems Manager requests on instances created from AMIs for versions of Windows Server prior to Windows Server 2016 that were published before November 2016.

Instances created from AMIs for versions of Windows Server prior to Windows Server 2016 that were published after November 2016 include the EC2Config service and SSM Agent. EC2Config performs all of the tasks described earlier, and SSM Agent processes requests for Systems Manager capabilities like Run Command and State Manager.

You can use Run Command to upgrade your existing instances to use to the latest version of the EC2Config service and SSM Agent. For more information, see Update SSM Agent using Run Command in the AWS Systems Manager User Guide.

EC2Config tasks

EC2Config runs initial startup tasks when the instance is first started and then disables them. To run these tasks again, you must explicitly enable them prior to shutting down the instance, or by running Sysprep manually. These tasks are as follows:

  • Set a random, encrypted password for the administrator account.

  • Generate and install the host certificate used for Remote Desktop Connection.

  • Dynamically extend the operating system partition to include any unpartitioned space.

  • Execute the specified user data (and Cloud-Init, if it's installed). For more information about specifying user data, see Run commands when you launch an EC2 instance with user data input.

EC2Config performs the following tasks every time the instance starts:

  • Change the host name to match the private IP address in Hex notation (this task is disabled by default and must be enabled to run at instance start).

  • Configure the key management server (AWS KMS), check for Windows activation status, and activate Windows as necessary.

  • Mount all Amazon EBS volumes and instance store volumes, and map volume names to drive letters.

  • Write event log entries to the console to help with troubleshooting (this task is disabled by default and must be enabled to run at instance start).

  • Write to the console that Windows is ready.

  • Add a custom route to the primary network adapter to enable the following IP addresses when a single NIC or multiple NICs are attached: 169.254.169.250, 169.254.169.251, and 169.254.169.254. These addresses are used by Windows Activation and when you access instance metadata.

    Note

    If the Windows OS is configured to use IPv4, these IPv4 link-local addresses can be used. If the Windows OS has the IPv4 network protocol stack disabled and uses IPv6 instead, add [fd00:ec2::250] in place of 169.254.169.250 and 169.254.169.251. Then add [fd00:ec2::254] in place of 169.254.169.254.

EC2Config performs the following task every time a user logs in:

  • Display wallpaper information to the desktop background.

While the instance is running, you can request that EC2Config perform the following task on demand:

EC2Config settings files

The settings files control the operation of the EC2Config service. These files are located in the C:\Program Files\Amazon\Ec2ConfigService\Settings directory:

  • ActivationSettings.xml—Controls product activation using a key management server (AWS KMS).

  • AWS.EC2.Windows.CloudWatch.json—Controls which performance counters to send to CloudWatch and which logs to send to CloudWatch Logs.

  • BundleConfig.xml—Controls how EC2Config prepares an instance store-backed instance for AMI creation.

  • Config.xml—Controls the primary settings.

  • DriveLetterConfig.xml—Controls drive letter mappings.

  • EventLogConfig.xml—Controls the event log information that's displayed on the console while the instance is booting.

  • WallpaperSettings.xml—Controls the information that's displayed on the desktop background.

ActivationSettings.xml

This file contains settings that control product activation. When Windows boots, the EC2Config service checks whether Windows is already activated. If Windows is not already activated, it attempts to activate Windows by searching for the specified AWS KMS server.

  • SetAutodiscover—Indicates whether to detect a AWS KMS automatically.

  • TargetKMSServer—Stores the private IP address of a AWS KMS. The AWS KMS must be in the same Region as your instance.

  • DiscoverFromZone—Discovers the AWS KMS server from the specified DNS zone.

  • ReadFromUserData—Gets the AWS KMS server from UserData.

  • LegacySearchZones—Discovers the AWS KMS server from the specified DNS zone.

  • DoActivate—Attempts activation using the specified settings in the section. This value can be true or false.

  • LogResultToConsole—Displays the result to the console.

BundleConfig.xml

This file contains settings that control how EC2Config prepares an instance for AMI creation.

  • AutoSysprep—Indicates whether to use Sysprep automatically. Change the value to Yes to use Sysprep.

  • SetRDPCertificate—Sets a self-signed certificate to the Remote Desktop server. This enables you to securely RDP into the instances. Change the value to Yes if the new instances should have the certificate.

    This setting is not used for instances with operating system versions prior to Windows Server 2016, because they can generate their own certificates.

  • SetPasswordAfterSysprep—Sets a random password on a newly launched instance, encrypts it with the user launch key, and outputs the encrypted password to the console. Change the value of this setting to No if the new instances should not be set to a random encrypted password.

Config.xml

Plug-ins

  • Ec2SetPassword—Generates a random encrypted password each time you launch an instance. This feature is disabled by default after the first launch so that reboots of this instance don't change a password set by the user. Change this setting to Enabled to continue to generate passwords each time you launch an instance.

    This setting is important if you are planning to create an AMI from your instance.

  • Ec2SetComputerName—Sets the host name of the instance to a unique name based on the IP address of the instance and reboots the instance. To set your own host name, or prevent your existing host name from being modified, you must disable this setting.

  • Ec2InitializeDrives—Initializes and formats all volumes during startup. This feature is enabled by default.

  • Ec2EventLog—Displays event log entries in the console. By default, the three most recent error entries from the system event log are displayed. To specify the event log entries to display, edit the EventLogConfig.xml file located in the EC2ConfigService\Settings directory. For information about the settings in this file, see Eventlog Key.

  • Ec2ConfigureRDP—Sets up a self-signed certificate on the instance, so users can securely access the instance using Remote Desktop. This setting is not used for instances with operating system versions prior to Windows Server 2016, because they can generate their own certificates.

  • Ec2OutputRDPCert—Displays the Remote Desktop certificate information to the console so that the user can verify it against the thumbprint.

  • Ec2SetDriveLetter—Sets the drive letters of the mounted volumes based on user-defined settings. By default, when an Amazon EBS volume is attached to an instance, it can be mounted using the drive letter on the instance. To specify your drive letter mappings, edit the DriveLetterConfig.xml file located in the EC2ConfigService\Settings directory.

  • Ec2WindowsActivate—The plug-in handles Windows activation. It checks to see if Windows is activated. If not, it updates the AWS KMS client settings, and then activates Windows.

    To modify the AWS KMS settings, edit the ActivationSettings.xml file located in the EC2ConfigService\Settings directory.

  • Ec2DynamicBootVolumeSize—Extends Disk 0/Volume 0 to include any unpartitioned space.

  • Ec2HandleUserData—Creates and runs scripts created by the user on the first launch of an instance after Sysprep is run. Commands wrapped in script tags are saved to a batch file, and commands wrapped in PowerShell tags are saved to a .ps1 file (corresponds to the User Data checkbox on the Ec2 Service Properties system dialog).

  • Ec2ElasticGpuSetup—Installs the Elastic GPU software package if the instance is associated with an elastic GPU.

  • Ec2FeatureLogging—Sends Windows feature installation and corresponding service status to the console. Supported only for the Microsoft Hyper-V feature and corresponding vmms service.

Global Settings

  • ManageShutdown—Ensures that instances launched from Amazon S3-backed AMIs do not terminate while running Sysprep.

  • SetDnsSuffixList—Sets the DNS suffix of the network adapter for Amazon EC2. This allows DNS resolution of servers running in Amazon EC2 without providing the fully qualified domain name.

    Note

    This adds a DNS suffix lookup for the following domain and configures other standard suffixes. For more information about how launch agents set DNS suffixes, see Configure DNS Suffix for EC2 Windows launch agents.

    region.ec2-utilities.amazonaws.com

  • WaitForMetaDataAvailable—Ensures that the EC2Config service will wait for metadata to be accessible and the network available before continuing with the boot. This check ensures that EC2Config can obtain information from metadata for activation and other plug-ins.

  • ShouldAddRoutes—Adds a custom route to the primary network adapter to enable the following IP addresses when multiple NICs are attached: 169.254.169.250, 169.254.169.251, and 169.254.169.254. These addresses are used by Windows Activation and when you access instance metadata.

  • RemoveCredentialsfromSyspreponStartup—Removes the administrator password from Sysprep.xml the next time the service starts. To ensure that this password persists, edit this setting.

DriveLetterConfig.xml

This file contains settings that control drive letter mappings. By default, a volume can be mapped to any available drive letter. You can mount a volume to a particular drive letter as follows.



  
    
    
  
  . . .

  • VolumeName—The volume label. For example, My Volume. To specify a mapping for an instance storage volume, use the label Temporary Storage X, where X is a number from 0 to 25.

  • DriveLetter—The drive letter. For example, M:. The mapping fails if the drive letter is already in use.

EventLogConfig.xml

This file contains settings that control the event log information that's displayed on the console while the instance is booting. By default, we display the three most recent error entries from the System event log.

  • Category—The event log key to monitor.

  • ErrorType—The event type (for example, Error, Warning, Information.)

  • NumEntries—The number of events stored for this category.

  • LastMessageTime—To prevent the same message from being pushed repeatedly, the service updates this value every time it pushes a message.

  • AppName—The event source or application that logged the event.

WallpaperSettings.xml

This file contains settings that control the information that's displayed on the desktop background. The following information is displayed by default.

  • Hostname—Displays the computer name.

  • Instance ID—Displays the ID of the instance.

  • Public IP Address—Displays the public IP address of the instance.

  • Private IP Address—Displays the private IP address of the instance.

  • Availability Zone—Displays the Availability Zone in which the instance is running.

  • Instance Size—Displays the type of instance.

  • Architecture—Displays the setting of the PROCESSOR_ARCHITECTURE environment variable.

You can remove any of the information that's displayed by default by deleting its entry. You can add additional instance metadata to display as follows.


  display_name
  metadata
  meta-data/path

You can add additional System environment variables to display as follows.


  display_name
  EnvironmentVariable
  variable-name
InitializeDrivesSettings.xml

This file contains settings that control how EC2Config initializes drives.

By default, EC2Config initialize drives that were not brought online with the operating system. You can customize the plugin as follows.


    setting

Use a settings group to specify how you want to initialize drives:

FormatWithTRIM

Enables the TRIM command when formatting drives. After a drive has been formatted and initialized, the system restores TRIM configuration.

Starting with EC2Config version 3.18, the TRIM command is disabled during the disk format operation by default. This improves formatting times. Use this setting to enable TRIM during the disk format operation for EC2Config version 3.18 and later.

FormatWithoutTRIM

Disables the TRIM command when formatting drives and improves formatting times in Windows. After a drive has been formatted and initialized, the system restores TRIM configuration.

DisableInitializeDrives

Disables formatting for new drives. Use this setting to initialize drives manually.