Creating a System Disk Image from an ECS

Scenarios

If you have created and configured an ECS based on your service requirements (for example, by installing software and setting up an application environment), you can use this ECS to create a system disk image. Then, all new ECSs created from this image will have the same software and environment preinstalled.

Creating a system disk image does not affect services on the cloud server or cause data loss.

Video Tutorial

Background

The following figure shows the process of creating a system disk image from a cloud server and using the image to create new cloud servers.

Figure 1 Creating a system disk image and using it to create new cloud servers

• System disk images are often used for application scale-out. They can also be used for hybrid cloud deployment. You can create system disk images for resource synchronization on and off cloud. The procedure is as follows:
  1. Create a system disk image from a cloud server.
     

     If the cloud server is created from any of the following images, the system disk image cannot be exported:

     • ISO images

     • Private images created from a SUSE, Red Hat, Ubuntu, Oracle Linux, or Windows public image
     • Private images created from a KooGallery image
  2. Export the image to an OBS bucket. For details, see Exporting an Image.
  3. Download the image file from the OBS bucket.
• You can create an image from a running cloud server.

  The image creation does not affect services on the cloud server.

  In this process, do not stop, start, or restart the cloud server, or the image creation may fail.

• The time required for creating an image depends on the system disk size, network quality, and the number of concurrent tasks.
• A system disk image will be created in the same region as the cloud server that was used to create it. For example, if a cloud server is located in the CN-Hong Kong region, the system disk image created from that cloud server will also be located in the CN-Hong Kong region. If you want to use the image in another region, you must first replicate it to that region. For details, see Replicating Images Across Regions.
• If a cloud server has expired or been released, you can use the system disk image created from the cloud server to restore it.

Constraints

The system disk capacity of the cloud server used to create a system disk image must be no greater than 1 TB.

If the capacity is greater than 1 TB, you can only use it to create a full-ECS image.

Prerequisites

Before creating a private image from a cloud server:

• Delete any sensitive data the ECS may contain.
• Ensure that the ECS is in the Running or Stopped state.
• Complete all operations in Windows Private Images or Linux Private Images to configure the cloud server.
• If the cloud server is a BMS, understand the related constraints and prerequisites. For details, see Creating a Private Image from a BMS.

Procedure

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.

      You need to set parameters in two areas: Image Type and Source and Image Information. For details about the parameters, see Table 1 and Table 2.

      Figure 2 Image type and source
      

      Table 1 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.	Create 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 only 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
      Source	A source is the original data required for creating a private image. Select a source based on your requirements. Generally, a data source can be a cloud server, a CSBS backup, or a CBR backup.	ECS

      Figure 3 Image information
      

      Table 2 Parameters for configuring image information

      Parameter	Description	Example Value
      Encryption	A private image created from an unencrypted ECS is also unencrypted. A private image created from an encrypted ECS is also encrypted. NOTE: The encryption attribute cannot be changed during image creation. After the image is created, you can change it based on Replicating Images Within a Region.	-
      Name	Set a name for the image.	-
      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. If you do not comply with the tag policies, images may fail to be created. Contact the organization administrator to learn more about the tag policies. Each tag consists of a key and a value. A key contains a maximum of 36 characters, and a value contains a maximum of 43 characters. A key cannot be left blank or be an empty string. A value cannot be left blank but can be an empty string. An image can have a maximum of 10 tags.	-
      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 and view the new system disk image.

   The time required for creating an image depends on the ECS system disk size, network quality, and the number of concurrent tasks. When the image status changes to Normal, the image creation is complete.

   

   • Do not perform any operation on the selected ECS or its associated resources during image creation.
   • An ECS created from an encrypted image is also encrypted. The key used for encrypting the ECS is the same as that used for encrypting the image.
   • An image created from an encrypted ECS is also encrypted. The key used for encrypting the image is the same as that used for encrypting the ECS.
   • The size of a new image is determined based on the maximum disk space that was ever used, not the current disk usage.

Follow-up Procedure

After a system disk image is created, you can:

• Use the image to create new cloud servers. For details, see Creating an ECS from an Image.
• Use the image to change the OSs of existing cloud servers. For details, see Changing the OS.