Creating a System Disk Image from an External Image File

Constraints

Process

Figure 1 shows the process of creating a private image.

Figure 1 Creating a system disk image

The steps are as follows:

1. Prepare an image file that meets the cloud platform requirements. For details, see Prepare an Image File.
2. Upload the image file to your OBS bucket. For details, see Upload an Image File.
3. On the IMS console, select the uploaded image file and register it as a private image. For details, see Registering an Image.
4. After the private image is registered, you can use it to create ECSs. For details, see Create an ECS from an Image.

Video Tutorial

Prepare an Image File

Before preparing an image file, you need to understand the constraints in this section and known issues (see Known Issues).

The initial configuration mentioned in Preparations for Creating a Private Image must be completed on the source VM before an image file is exported from it.

If you did not configure it, use the image file to create an ECS, configure the ECS, and use the ECS to create a private image. For details, see What Do I Do If a Windows Image File Is Not Pre-Configured When I Use It to Register a Private Image?

Upload an Image File

You are advised to use OBS Browser+ to upload external image files to OBS buckets. For details, see OBS Browser+ Best Practices.

For how to download OBS Browser+, see https://support.huaweicloud.com/intl/en-us/browsertg-obs/obs_03_1003.html.

• The bucket file and the image to be registered must belong to the same region.
• Only unencrypted external image files or those encrypted using SSE-KMS can be uploaded to an OBS bucket.
• Only unencrypted ISO image files can be uploaded to an OBS bucket.
• In an OBS bucket, only unencrypted external image files can use fast import.
• The storage class of the OBS bucket must be Standard.
• If you want to create a data disk image along with the system disk image, you also need to upload an image file containing data disks to the OBS bucket. You can create one system disk image and no more than three data disk images.

Registering an Image

1. Log in to the IMS console.
2. Create a system disk image.
   1. Click Create Image in the upper right corner.
   2. Set image parameters as required.

      Set parameters in two areas: Image Type and Source and Image Information. For details about the parameters, see Table 2 and Table 3.

      Figure 2 Image type and source
      

      Table 2 Parameters for configuring the image type and source

      Parameter	Description	Example Value
      Region	Resources in different regions cannot communicate with each other over an intranet. For low latency and fast access, select a region close to where your services will be provided.	-
      Type	Private images can be created or imported.	Import Image
      Image Type	A private image contains an OS or service data, preinstalled public applications, and a user's personal applications. Private images are only available to the users who created them. A private image can be a system disk image, data disk image, ISO image, or full-ECS image. A system disk image contains an OS and preinstalled software for various services. You can use a system disk image to create ECSs and migrate your services to the cloud. A data disk image contains only service data. You can use a data disk image to create EVS disks and use them to migrate your service data to the cloud. An ISO image is created from an external ISO image file. It is a special image that is not available on the ECS console. It can only be used to provision temporary cloud servers. A full-ECS image contains an OS, preinstalled software, and service data. A full-ECS image is created using differential backups and the creation takes less time than creating a system or data disk image that has the same disk capacity.	System disk image
      Select Image File	Select the bucket storing the image file from the bucket list and then select the image file. NOTE: The image file format must be VHD, ZVHD, VMDK, QCOW2, RAW, ZVHD2, VHDX, QCOW, VDI, or QED. For details about common image formats, see Common Image Formats. Only image files that have been uploaded to a Standard OBS bucket are available for use. The size of each image file must be less than 128 GiB, except for ZVHD2 and RAW image files. The image file must have been configured with necessary settings. For details, see How Do I Configure an ECS, a BMS, or an Image File Before I Use It to Create an Image? The format and size of the new image may be different from the source image file. Fast Create can be used to quickly create an image. However, the image file must be converted to the RAW or ZVHD2 format and must be optimized. For details, see Overview. Before creating an image, check the known OS issues. For details, see Known Issues.	-
      Fast Create	This parameter is available only when you select a ZVHD2 or RAW image file. This function enables fast image creation and supports import of large files (maximum: 1 TiB) as long as the files to be uploaded are converted to ZVHD2 or RAW format and optimized. If you have already prepared an image file that meets the requirements, select Enable Fast Create and select the confirmation checkbox in the Image File Preparation row. NOTE: To learn how to convert image file formats and generate bitmap files, see Fast Import of an Image File.	-

      Figure 3 Image information
      

      

      Table 3 Parameters for configuring image information

      Parameter	Description	Example Value
      Enable automatic configuration	If you select this option, the system will automatically check and optimize the image file. For details, see What Will the System Do to an Image File When I Use the File to Register a Private Image?	-
      Auto sign	If you select this option, the system will sign the image for high data reliability. Key Name: Select a key from the drop-down list. The key is used to sign the image. If there is no key available, log in to the DEW console and create a key. Key ID: After you select a key, its ID will be automatically displayed. NOTE: A signed image cannot be shared with other users. Check on the console to see if Auto sign is available.	-
      Function	Indicates whether the image is used to create an ECS or BMS. The value can be ECS system disk image or BMS system disk image.	ECS system disk image
      Architecture	The value can be x86 or ARM. NOTE: If the system identifies that the architecture in the image file is different from what you set here, the identified architecture will be used. If the system fails to identify an architecture, the architecture you set will be used.	x86
      Boot Mode	This parameter is optional. Select the same boot mode as that in the image file, or the ECS created using this image cannot be booted. After you select the boot mode, the cloud platform will configure the corresponding boot settings for the image. The boot mode can be BIOS or UEFI. For details about the differences between them, see How Is BIOS Different from UEFI? For details about which OSs support UEFI boot, see OSs supporting UEFI Boot Mode. NOTE: If the image file uses the Arm architecture, only the UEFI mode is available.	BIOS
      OS	To ensure that the image can be created and used properly, select an OS consistent with that in the image file. If you do not select an OS, the system attempts to automatically identify the OS in the image file. NOTE: If the system identifies that the OS in the image file is different from the one you select here, the identified OS will be used. If the system fails to identify an OS, the OS you select will be used. If the OS you selected or the OS identified by the system is different from the actual OS, the performance of the ECSs created using the image file may be affected.	-
      License Type	Bring Your own license (BYOL) is supported. If you already have a license for the OS, you can directly use the license after creating an ECS and do not need to apply for a new one. This parameter is only available for Windows.	-
      System Disk	Set the system disk capacity (value range: 40 GiB to 1,024 GiB). This value must be no less than the size of the system disk in the image file. NOTE: If the uploaded VHD image is generated using qemu-img or similar tools, check the system disk capacity by referring to Why Did My VHD Upload Fail? Why Does the System Say the System Disk in the VHD Image File Is Larger Than What I Specified on the Management Console?	-
      Data Disk	You can also add data disks to the image. You need to obtain an image file containing data disks in advance. This function is used to migrate VMs and data disks from other platforms to the current platform. To add a data disk, click , configure the data disk size, and click Select Image File. In the displayed dialog box, select the target bucket and then the target image file containing the data disk. NOTE: A maximum of three data disks can be added.	-
      Name	Set an image name that is easy to identify.	-
      Encryption	This parameter is optional. If you want to encrypt the image, select KMS encryption and select the key to be used from the key list. After you select KMS encryption, the system will create a default key ims/default. You can also select a key from the key list. For details about how to encrypt an image, see Introduction.	-
      Enterprise Project	This parameter is for enterprise users. To use this function, contact customer service to enable it. An enterprise project groups cloud resources, so you can manage resources and users by project. The default project is default. Select an enterprise project from the drop-down list. For more information, see Accessing the Enterprise Center.	default
      Tag	This parameter is optional. Set tag keys and values for the image to make identification and management easier. You are advised to create predefined tags in TMS. For details, see Creating Predefined Tags. NOTE: If your organization has configured tag policies for images, you need to add tags to your images based on the policies. Otherwise, tags may fail to be added. For details about image tag format, see Image Tag Format.	-
      Description	This parameter is optional. Enter a description for the image.	-
      Agreement	Read and agree to the Image Disclaimer	-

   3. Click Next. Confirm the settings and click Submit.

3. Go back to the private image list. The image is successfully registered when its status becomes Normal.

   If you add data disks during image creation, a system disk image and data disk images will be generated. The number of data disk images depends on the number of data disks you add (a maximum of 3).

   

   The time required for registering an image file as a private image varies depending on the image file size.

Create an ECS from an Image

Create an ECS by referring to Creating an ECS from an Image.

Note the following when setting the parameters:

• Region: Select the region where the private image is located.
• Specifications: Select a flavor based on the OS type in the image and the OS versions described in OSs Supported for Different Types of ECSs.
• Image: Select Private image and then the created image from the drop-down list.
• (Optional) Data Disk: Add data disks. These data disks are created from a data disk image generated together with a system disk image. In this way, you can migrate the data of data disks together with system disk data from the VM on the original platform to the current cloud platform.

Follow-up Procedure

After a system disk image is created, you can use it to change the OS of an ECS. For details, see Changing the OS.