This topic provides answers to frequently asked questions (FAQ) about ECS images.

What are the differences between Aliyun Linux and Aliyun Linux 2?

Aliyun Linux 2 differs in the following aspects:
  • Aliyun Linux 2 is optimized for containers to better support cloud-native applications.
  • Aliyun Linux 2 is equipped with an updated Linux kernel and updated user-mode packages.

How do I use Aliyun Linux 2 in Alibaba Cloud public cloud?

Alibaba Cloud provides an official public image for Aliyun Linux 2. You can select this image when you create an ECS instance.

Will I be charged for using Aliyun Linux 2 in Alibaba Cloud ECS?

No. Aliyun Linux 2 images are free of charge. You will only be charged for the ECS instances to which the images are applied.

Which ECS instance types does Aliyun Linux 2 support?

Aliyun Linux 2 supports most ECS instance types, including ECS Bare Metal Instance.
Note Aliyun Linux 2 cannot be used with ECS instances that use the Xen virtual machine platform or with ECS instances in classic networks. Aliyun Linux 2 will not be displayed as an option on the page for creating these instances.

Does Aliyun Linux 2 support 32-bit applications or databases?

No. Aliyun Linux 2 does not support 32-bit applications or databases.

Does Aliyun Linux 2 provide a graphical user interface (GUI) desktop?

No. Aliyun Linux 2 does not provide a GUI desktop.

Can I view the source code of Aliyun Linux 2 components?

Yes. Aliyun Linux 2 is completely open source. You can use the yumdownloader tool or visit the official Alibaba Cloud download pages to download the source code package. You can also download the source code tree of the Aliyun Linux kernel from GitHub.

Is Aliyun Linux 2 backward-compatible with the current Aliyun Linux version?

Yes. Aliyun Linux 2 is fully compatible with Aliyun Linux 17.01.
Note You may need to re-compile a compiled kernel module on Aliyun Linux 2 before it can be used.

Can I use Aliyun Linux 2 on local computers?

No. Aliyun Linux 2 supports only Alibaba Cloud ECS, not third-party virtualization platforms.

Which third-party applications can run on Aliyun Linux 2?

Aliyun Linux 2 is binary compatible with CentOS 7.6.1810. Applications that can run on CentOS can also run on Aliyun Linux 2.

What are the advantages of Aliyun Linux 2 compared with other Linux operating systems?

Aliyun Linux 2 is binary compatible with CentOS 7.6.1810 and provides differentiated operating system features.

Compared with CentOS and RHEL, Aliyun Linux 2 has the following advantages:
  • Updates are released at a faster pace. Updated Linux kernels, user-mode software, and toolkits are provided.
  • Aliyun Linux 2 works out of the box and requires the minimal configuration.
  • Aliyun Linux 2 is optimized to work with the optimized hypervisor and maximizes performance for users.
  • Unlike RHEL, Aliyun Linux 2 does not have any runtime charges. Different from CentOS, Alibaba Cloud provides commercial support for Aliyun Linux 2.

How does Aliyun Linux 2 protect data security?

Aliyun Linux 2 is binary compatible with CentOS 7.6.1810 and RHEL 7.6 and complies with the RHEL safety specifications. Aliyun Linux 2 uses the following tools to protect your data:
  • Uses industry-standard vulnerability scan and security test tools to perform periodical security scanning.
  • Periodically assesses the CVE patch updates of CentOS 7 to fix operating system security vulnerabilities.
  • Supports existing solutions of Alibaba Cloud for operating system security enhancement.
  • Uses the same mechanism as CentOS 7 to release user security alerts and patch updates.

Does Aliyun Linux 2 support data encryption?

Yes. Aliyun Linux 2 uses the CentOS 7 data encryption toolkit implemented by Key Management Service (KMS) to encrypt data.

How do I grant permissions to manage Aliyun Linux 2?

You can grant management permissions in Aliyun Linux 2 in the same manner as you would do in Alibaba Cloud CentOS 7. This means the same commands can be used to grant management permissions in both CentOS 7 and Aliyun Linux 2.

Can I replace the selected image of an ECS instance?

Yes. In the ECS console, you can replace the image of your ECS instance by selecting Replace System Disk. Note that replacing an image will result in the loss of system disk data. Make sure that you have backed up your data before replacing the system disk.

Do the system disks of ECS instances support KMS encryption? How do I use KMS encryption through Terraform or Packer?

The system disks of ECS instances support KMS encryption. After you select KMS encryption, ECS automatically creates a dedicated CMK in the region where KMS is used. For more information, see ECS disk encryption.

BYOK encryption and Packer encryption will be supported soon.

In Terraform, you can set the encrypted parameter to enable or disable KMS encryption. For more information, see alicloud_disks.

What are the differences and relationships between snapshots and images?

Images and snapshots differ in the following ways:
  • Images can be directly used to create ECS instances, while snapshots cannot.
  • A snapshot can be a data backup of either the system disk or a data disk of an ECS instance, while an image must contain the system disk data of an ECS instance.
  • A snapshot can only be used to restore data of the current ECS instance disk, while an image can be used to replace the system disk of any ECS instance or create a new ECS instance.
  • Snapshots cannot be used across regions. To restore instance data in other regions, use a custom image. For more information, see Copy custom images.
  • Images and snapshots apply to different scenarios: Here are a few scenarios where snapshots and custom images are used:
    Scenarios for snapshots
    • Regular backup of data. Automatic snapshots are created to back up data on a daily, weekly, or monthly basis based on automatic snapshot policies.
    • Temporary backup of data. Examples:
      • Before a temporary system change such as system update and application release, manually create a snapshot to back up the system data.
      • Create a snapshot to back up data before the system disk is resized.
      • To migrate data to another disk, create a snapshot of the source disk and use the snapshot to overwrite the data on the destination disk.
    Scenarios for custom images
    • Back up systems that will not change in a short term, such as applications and systems that have been released or updated.
    • Create new ECS instances. For example, you can use a custom image to create an ECS instance with multiple applications deployed.
    • Migrate systems and data. For example, you can migrate ECS instances from classic networks to VPCs.
    • Restore systems across regions and zones.

The relationships between snapshots and images are as follows:

When you create a custom image from an instance, ECS creates a snapshot for each disk of the instance. The created custom image contains the snapshots of all the disks of this ECS instance. For more information, see Create a custom image by using an instance.

You can also create custom images by using system disk snapshots. For more information, see Create a custom image by using a snapshot.

Can I use a snapshot of a data disk to create a custom image?

Only system disks can be used to create custom images. Data disks cannot be used to create custom images.

However, you can add a snapshot of a data disk when using a snapshot of a system disk to create a custom image. For more information, see Create a custom image from a snapshot.

How do I view the data disk usage?

You can run the df command to view the data disk usage and where file systems are mounted. Example: df –lh.

You can run the fdisk command to view the partition information of a data disk. Example: fdisk -l.

How do I unmount file systems and delete disk table data?

Assume that /dev/hda5 is mounted to /mnt/hda5. You can run any of the following commands to unmount the mounted file systems:
umount /dev/hda5
umount /mnt/hda5
umount /dev/hda5 /mnt/hda5
/etc/fstab is an important profile in Linux systems. It contains detailed information about file systems and storage devices mounted to the system at system startup.
If you do not want to mount a partition when you start an instance, delete the corresponding statement from the /etc/fstab file. For example, after the following statement is deleted from the /etc/fstab file, xvdb1 will not be loaded at system startup.
/dev/xvdb1 /leejd ext4 defaults 0 0
The following table lists other important profiles in Linux systems.
Profile Description Risk of modifying the profile
/etc/issue*, /etc/*-release, /etc/*_version The system release profile Modifying /etc/issue* causes system creation and release recognition failures.
/boot/grub/menu.lst, /boot/grub/grub.conf The system boot profile Modifying /boot/grub/menu.lst causes kernel load and system boot failures.
/etc/fstab The profile for mounting partitions at system startup Modifying this file causes partition load and system boot failures.
/etc/shadow The system password-related profile If this file is changed to read-only, the password file cannot be modified and the system cannot be created.
/etc/selinux/config The system security policy profile Modifying /etc/selinux/config to enable SELinux causes system boot failures.

How do I confirm that a data disk has been unmounted and that a new custom image can be created?

Perform the following steps:
  1. Confirm that the statement used to automatically mount data disk partitions has been deleted from the /etc/fstab file.
  2. Run the mount command to view the mount information of all devices. Confirm that information about corresponding data disk partitions is not displayed in the command output.

Does a custom image still exist after its corresponding instance is released?

Yes.

Is the custom image that an instance is created from affected when the instance expires or its data is deleted? Are instances created from the custom image affected?

No. The custom image and the instances are not affected.

Can I replace the operating system of an instance created from a custom image? Can the custom image still be used after the replacement?

Yes. You can replace the operating system of an instance created from a custom image. The custom image still can be used after the replacement.

Can I select a custom image with a different operating system when replacing the system disk of an instance?

Yes. For more information, see Replace the system disk (non-public image).
Note When a custom image is used to replace a system disk, all of the original system disk data is overwritten.

Can I use a custom image to overwrite the system disk data of an ECS instance?

Yes. For more information, see Replace the system disk (non-public image).
Note The custom image will overwrite all data in the system disk of the ECS instance.

Can I upgrade the CPU, memory, bandwidth, and hard disks of an ECS instance created from a custom image?

Yes.

Can I use a custom image across regions?

No. A custom image can be used only within a single region. For example, a custom image created from an instance in the China (Hangzhou) region cannot be used to create an ECS instance in the China (Shanghai) region.

If you want to use a custom image across regions, copy the image to the destination region. For more information, see Copy custom images.

Can a custom image created from a subscription instance be used to create a pay-as-you-go instance?

Yes. The usage of custom images has nothing to do with the billing methods of instances.

When I create an ECS instance from a custom image, I specify a greater capacity for the instance system disk than the size of the system disk snapshot contained in the image. However, when I log on to the new ECS instance, I find that the system disk capacity has not been expanded. What can I do?

The system disk capacity of an instance created from a custom image may fail to expand due to any of the following reasons: the cloud-init service is not installed, the cloud-init service fails, or the file systems do not support the capacity expansion.

You can manually expand the system disk capacity.

Why do I need to comment out mounted items when creating a custom image or an ECS instance?

When you create an ECS instance from a custom image, the following conditions can cause disks to fail to be mounted:
  • The created ECS instance does not have a data disk.
  • The data disk is a new disk and has not been formatted or partitioned.
  • The mounted disks are not commented out in the /etc/fstab file in the created custom image.
The following content describes an example of data disk mounting failure. In this example, the data disk of an ECS instance created from a custom image is not partitioned, and the mounted disks are not commented out in the /etc/fstab file in the custom image.
  1. The data disk of the ECS instance is not partitioned, as shown in the following figure.
  2. In the ECS instance, the mounted disks are not commented out in /etc/fstab, as shown in the following figure.
  3. When the instance starts, the data disk is mounted based on the configurations in /etc/fstab. However, the mount operation fails because the data disk is not partitioned, as shown in the following figure.

When you are creating an ECS instance with data disks from partitioned and formatted data disks snapshots, you do not need to comment out the mounted disks.

If the problem persists, submit a ticket.

How do I configure and use a private Docker image registry?

Image management is at the core of Docker. To allow organizations to share images internally, Docker has created the open source docker-registry on GitHub to act as a repository of private Docker images.

Start docker-registry that supports Alibaba Cloud OSS. You can download docker-registry from GitHub and install it, and run the pip install docker-registry-driver-alioss command to install the OSS driver.
  1. Run docker-registry.
     docker run -e OSS_BUCKET=-e STORAGE_PATH=/docker/ -e OSS_KEY=-e OSS_SECRET=-p 5000:5000 -d chrisjin/registry:ali_oss
  2. Configure config.yml.
     ```local: &local
     <<: *common
     storage: alioss
     storage_path: _env:STORAGE_PATH:/devregistry/
     oss_bucket: _env:OSS_BUCKET[:default_value]
     oss_accessid: _env:OSS_KEY[:your_access_id]
     oss_accesskey: _env:OSS_SECRET[:your_access_key]```
  3. Start docker-registry.
     DOCKER_REGISTRY_CONFIG=[your_config_path] gunicorn -k gevent -b 0.0.0.0:5000 -w 1 docker_registry.wi:application

If the problem persists, submit a ticket.

How do I clone an ECS instance?

You can clone the environment and data of an existing ECS instance under your account to create identical ECS instances within the same region.
  1. Select the ECS instance that you want to clone and create snapshots for its system disk and data disks. For more information, see Create a snapshot.
    Note To ensure data consistency, only create snapshots when the instance is in the Stopped state.
  2. Use the system disk snapshot to create a custom image. In the Create Custom Image dialog box, select Add Data Disk Snapshot and click Add to add one or more data disk snapshots to the image. For more information, see Create a custom image from a snapshot.
  3. Create an ECS instance by following the instructions in Create an instance by using the provided wizard. During the creation process, note the following items:
    • Region: You must select the same region as that of the cloned instance.
    • Image: Select Custom Image as the image type. Then, select the custom image you created in the previous step from the drop-down list.
      Note If the selected custom image contains one or more data disk snapshots, an equal number of data disks are automatically created from these snapshots. Each disk has the same size as the snapshot from which it is created. You can increase the size of a data disk but cannot decrease it.
In addition, you can use OOS to perform automatic cloning:
  • In different regions for the same account, you can use the ACS-ECS-CloneInstancesAcrossRegion public template to perform cross-region cloning.
  • In the same region for the same account, you can use the ACS-ECS-CloneInstancesAcrossAZ public template to perform cloning within a region.

Some custom images cannot be used to create I/O optimized instances. What can I do?

Some custom images cannot be used to create I/O optimized instances. If you want to use such a custom image to create an I/O optimized instance, submit a ticket that contains the image name.

Where do I view the progress of an image being imported? How long does it take to import an image?

You can view the progress of an image being imported on the Images page in the ECS console. It may take an extended period of time to import a custom image. The amount of time it takes to import an image depends on the image size and the number of concurrent import tasks in the queue.

Where do I view the progress of an image being created? How long does it take to create an image?

You can view the progress of an image being created on the Images page in the ECS console. The amount of time consumed depends on the size of the disk from which the image is created.

When do I need to copy a custom image?

Custom images can only be used within the same region and cannot be used directly across regions. You can copy custom images to achieve the following goals:
  • Deploy applications in ECS instances to multiple regions.
  • Migrate ECS instances to other regions.
  • Use custom images across regions.
You can copy a custom image from one region to another and use the custom image to create the same application environment within the destination region.

Which images can be copied?

Only custom images can be copied. Public images, Alibaba Cloud Marketplace images, and images shared by others cannot be copied.

Which regions support copying custom images?

All Alibaba Cloud regions support copying custom images.

How long does it take to copy a custom image?

Copying a custom image will transmit the image files from one region to another through the network. The amount of time it takes depends on the network transmission speed and the number of transmission tasks in the queue.

How am I charged when I copy a custom image?

You must perform the following operations to copy a custom image:
  1. Copy the snapshot from which the custom image is created from the source region to the destination region.
  2. Create a custom image from the snapshot copy in the destination region.
The preceding operations may incur the following fees:
  • Fees for traffic between the two regions. Alibaba Cloud has not started charging for cross-region traffic yet. For the latest billing details, see the official Alibaba Cloud website for announcements.
  • The copied snapshot consumes snapshot capacity. For the latest snapshot billing details, see the official Alibaba Cloud website for announcements.

What are the limits on the original and new images during the copy process?

The original image cannot be deleted during the copy process. The copy process can be canceled, but the new image will not be able to replace a system disk or create an ECS instance.

How do I copy the images under my Alibaba Cloud account to other regions under other Alibaba Cloud accounts?

You must copy your own images to the destination regions and then share the images to the intended Alibaba Cloud accounts. After the images are shared, they are displayed in the shared image lists of those accounts.

Are there any size limits on copying an image?

No. There are no size limits on copying an image. However, if you click Copy Image in the ECS console to copy an image whose size exceeds 500 GiB, you will be prompted to submit a ticket.

I copied an image to another region, and the image is in the Available state in the new region. When I used the image copy to create an instance in the new region, I was prompted with a message similar to "The specified image has been disabled or deleted." Why?

If you create a custom image from an Alibaba Cloud Marketplace image and then copy the custom image to another region, the image copy cannot be used to create an ECS instance in the new region. In other words, you cannot create an ECS instance by creating a custom image from an Alibaba Cloud Marketplace image and then copying the custom image to another region.

How do I migrate my ECS instance data from the International site (alibabacloud.com) to the China site (aliyun.com)?

You can do this by copying a custom image. For more information, see Copy custom images.

How many images can be shared to me?

100.

To how many users can an image be shared?

50.

I have accounts on different Alibaba Cloud sites. Can I share images between these accounts?

Yes. Any images, except for the custom images created from Alibaba Cloud Marketplace images, can be shared between your accounts on the China site (aliyun.com), International site (alibabacloud.com), and Japan site (jp.alibabacloud.com).

Do shared images consume my image quota?

No.

Are geographical limits available for creating instances from shared images?

Yes. Instances can only be created in the same regions as the shared images from which the instances are created.

What are the risks of creating an instance from a shared image?

The image owner can view how the image is shared and can delete the image. After a shared image is deleted by its owner, the system disks of the ECS instances that use this image cannot be reinitialized.

Alibaba Cloud does not guarantee the integrity and security of images shared by other accounts. Select images shared by trusted accounts. After you create an ECS instance from a shared image, you must log on to the ECS instance to check the security and integrity of the shared image.

What are the risks if I share a custom image to other accounts?

There is a risk that data and software can be leaked or stolen. Before you share a custom image to other accounts, check whether the image contains any sensitive or important data. After you share your image to other accounts, they can use the shared image to create ECS instances, which can then be used to create more custom images. Over this process, data can be spread repeatedly, creating a risk of data being disclosed beyond your original intentions.

After an account shares an image to me, can I share this image to another account?

No. Only the owner of an image can share it to other accounts.

After I share an image to others, can I still use this image to create an instance?

Yes. After you share an image to another account, you can still use the image to create an ECS instance. You can also continue to create a custom image from the ECS instance.

Can an image created from Instance A in one region be shared to Instance B in a different region?

  • If Instances A and B belong to the same account, you can copy the image to the region of Instance B and apply it to Instance B. For more information, see Copy custom images.
  • If Instances A and B belong to different accounts, you can copy the image to the region of Instance B and share the image to the account of Instance B. For more information, see Copy custom images and Share or unshare custom images.

Can Bring Your Own Licenses (BYOLs) be used when I import custom images?

Yes. You can configure the license types through the image import feature in the ECS console or by calling the ImportImage operation. For more information, see Import custom images and ImportImage.

What kinds of licenses can be used when I import custom images?

The following licenses can be used when you import custom images:
  • Aliyun licenses

    The licenses provided by Alibaba Cloud, mainly the licenses for Windows Server operating systems. If cloud-init has been installed on the imported image, Alibaba Cloud will use Key Management Service (KMS) to activate the operating system and provide Windows Server Update Services (WSUS).

  • BYOLs
    BYOLs are mainly used in the following scenarios:
    • Microsoft BYOLs
      Microsoft BYOLs are used in the following cases:
      • BYOLs implemented through Software Assurance (SA)

        Software programs that support License Mobility, such as SQL Server and SharePoint, can implement BYOLs by creating ECS instances.

      • Windows operating systems

        Windows Client Access Licenses (CALs) do not support License Mobility, so existing Windows licenses cannot be used in the shared hardware environment. You must deploy the Windows operating system in a dedicated physical environment, which can an Alibaba Cloud dedicated host or an ECS Bare Metal Instance. For more information, see Dedicated host documentation and ECS Bare Metal Instance documentation.

        For this ECS instance type, Alibaba Cloud does not provide KMS, WSUS and software technical support. You can contact Microsoft for software technical support.

      • No SA or BYOLs implemented through SA not supported

        This scenario is similar to the Windows operating system scenario. You can reuse software licenses that you have purchased and download and deploy software programs in a dedicated hardware environment.

    • Red Hat BYOLs

      Red Hat provides the Cloud Access program. If your Red Hat subscription to be migrated uses Bring Your Own Subscription (BYOS), you can register Red Hat Cloud Access. For more information, see Register Red Hat Cloud Access.

  • Auto licenses
    The default values are used. Depending on your operating system to be imported, a license type is configured automatically.
    • For the operating systems that Alibaba Cloud has signed licensing agreements and can provide official licenses, such as Windows Server operating systems, the license type will be Aliyun.
    • For other operating systems, such as noncommercial Linux images, the license type will be BYOL. Alibaba Cloud does not provide software technical support for these operating systems.

How are images imported with BYOLs charged?

No fees are charged for operating system components of images imported with BYOLs. This rule is applicable to ECS instances that are newly created, renewed, or reinitialized and ECS instances with their configurations changed.

How are BYOLs authenticated and subscribed through Alibaba Cloud when their subscription expires?

You can change images imported with BYOLs to images imported with Aliyun licenses.
  • For Windows Server operating systems, you can use official images of Alibaba Cloud. For more information about official images of Alibaba Cloud, see Public image overview.
  • For SQL Server and Red Hat images, you can obtain them in Alibaba Cloud Marketplace. For more information, see Marketplace images.

I want to export an image to my local computer for testing. What can I do?

By default, image files are exported as .raw.tar.gz files from which you can extract .raw files. You can search for the relevant documentation for using images in .raw format. Alibaba Cloud has no limit on how to use images in .raw format.

Can I delete a custom image after I use it to create an ECS instance?

You select Force Delete to forcibly delete the image. However, after you delete the image, the system disks of the ECS instances created from the image cannot be reinitialized. For more information, see Reinitialize a disk.

Can I delete a custom image from my account after I share the image to another account?

Yes. However, after you delete the shared image, the system disks of all ECS instances created from the image cannot be reinitialized. We recommend that you revoke all permissions that allow shared access to the custom image before you delete the image.

If I unshare custom image M to Account A, what will happen?

Account A can neither query Image M in the ECS console or by calling ECS API operations, nor use Image M to create ECS instances or replace system disks. If Account A has created ECS instances from Image M before the image is unshared, the system disks of these instances cannot be reinitialized.

When deleting an image, I am prompted with a message similar to "The specified image cannot be deleted because it is associated with instances." Why?

You may have created the image from a snapshot. To delete this image, you must select Force Delete. After you forcibly delete the image, instances created from it are still available, but their system disks cannot be reinitialized. For more information, see Delete custom images.

When I replace a system disk, can I select an image that contains data disks for the new system disk?

No. If you need to use a new image to replace a system disk, we recommend that you use the image to create a pay-as-you-go ECS instance and create a snapshot for the system disk of the new instance. Use the snapshot to create a custom image that contains only the system disk. Then, select the custom image when you replace the system disk.

I want to replace the operating system of my ECS instance by using an existing image. What can I do?

For information about how to use an existing image to replace the operating system of an ECS instance, see Change the operating system.
Note We recommend that you create snapshots to back up data before you proceed.

Can an image created from an instance under Account A be used to replace a disk under Account B?

Yes. You can share the image to Account B and then replace the disk. For more information, see Share or unshare custom images.
Notice To use an image to replace a system disk, ensure that the image contains only a system disk.

I am creating an ECS instance. Why is the total instance cost displayed when I select a custom image higher than that displayed when I select a public image?

This situation may occur in the following circumstances:
  • The custom image contains data disks. When such an image is selected, the costs of the data disks cause the total cost of the instance to be higher than that of an instance created using a public image.
  • The custom image is created from a paid public image such as Windows Server or Red Hat Enterprise Linux (RHEL).

What features do Alibaba Cloud Marketplace images provide?

A software environment such as the PHP, .NET, JAVA, or LANMP runtime environment and a variety of features such as control panel and website building systems are preinstalled on the operating systems in Alibaba Cloud Marketplace images. You can use Alibaba Cloud Marketplace images to deploy runtime environments or software applications to ECS instances.

What are the benefits of Alibaba Cloud Marketplace images?

You can use an Alibaba Cloud Marketplace image to create an ECS instance and deploy the preinstalled system environment or software of the image to the ECS instance. This eliminates the need to configure the environment or install software manually and enables you to create a ready-to-run runtime environment and conveniently build and manage services.

What server environments and scenarios do Alibaba Cloud Marketplace images support?

Alibaba Cloud Marketplace provides hundreds of high-quality third-party images. These images not only cover the deployment of PHP, .NET, JAVA, LAMP, and Docker virtual containers and other runtime environments, but can also meet personalized demands for website building, application development, and visual management.

Are Alibaba Cloud Marketplace images safe?

Our image service providers have a wealth of experience in system maintenance and environment configuration. All images are made based on the official Alibaba Cloud operating systems that are installed with Alibaba Cloud Security. All images have passed strict security reviews and are safe to use.

What can I do if I encounter a problem when installing or using an Alibaba Cloud Marketplace image?

View the service information on the purchase page and contact the image service provider by TradeManager, phone, or email. They will answer your questions promptly.

How do I purchase an Alibaba Cloud Marketplace image?

You can purchase it either from Alibaba Cloud Marketplace, or from the ECS instance purchase page when you create an ECS instance.

How long can I use a purchased image?

Theoretically, the image can be used indefinitely. However, an image is a piece of software and has its own lifecycle. In addition, image provides only provide services over a limited period of time, which is described in the commodity details.

Are Alibaba Cloud Marketplace images refundable?

Alibaba Cloud Marketplace images support money-back guarantee refunds within a certain period of time based on the Alibaba Cloud Marketplace rules. However, you will not receive a refund in the following situations:
  • You have deployed the purchased image to an ECS instance within the money-back guarantee period.
  • You have deployed the purchased image to an ECS instance before your application for a refund for this image is approved.
  • You can receive refunds only for images that have not been used.

Will any free Alibaba Cloud Marketplace images be available after Alibaba Cloud Marketplace images are commercialized?

A certain number of free Alibaba Cloud Marketplace images are still available. However, you will need to add them to your purchase at USD 0.00 before you can use them.

I bought an Alibaba Cloud Marketplace image in the China (Hangzhou) region. Can I use it to create an ECS instance or replace a system disk in the China (Beijing) region?

No. Alibaba Cloud Marketplace images are region-specific. You can only use it to create ECS instances or replace system disks within that region.

My ECS instance is created from an Alibaba Cloud Marketplace image. Do I need to make further payments when I upgrade or renew my ECS instance?

No. You do not need to make any further payments. You can use a purchased image to create as many instances as you like.

My ECS instance is created from an Alibaba Cloud Marketplace image. After my ECS instance is released, can I continue to use that image free of charge when I purchase a new ECS instance?

Yes.

I created an ECS instance from an Alibaba Cloud Marketplace image and then created a custom image from the instance. Do I need to pay for the custom image when I use it to create an ECS instance?

Yes. You must pay the original price of the Alibaba Cloud Marketplace image.

If I copy an Alibaba Cloud Marketplace image that I bought to another region to create an ECS instance, do I need to pay for the image?

Yes. You must pay the original price of the Alibaba Cloud Marketplace image.

I created an ECS instance from an Alibaba Cloud Marketplace image and then created a custom image from that instance. If I share the custom image to Account B, does Account B need to pay for the custom image when it uses the image to create an ECS instance?

Yes. Account B must pay the original price of the Alibaba Cloud Marketplace image.

Is a fee charged if I replace a system disk by using an Alibaba Cloud Marketplace image or an image that derives from an Alibaba Cloud Marketplace image?

It depends. If the current image of your ECS instance is a different version of the replacement image, no fee is charged. Otherwise, a fee is charged.

My ECS instance is using an Alibaba Cloud Marketplace image. Is a fee charged if I replace the system disk?

No.

How do I call an ECS API operation to use an Alibaba Cloud Marketplace image or a custom or share image that derives from an Alibaba Cloud Marketplace to create an ECS instance or replace a system disk?

  1. Check whether the used image is an Alibaba Cloud Marketplace image or an image that derives from an Alibaba Cloud Marketplace image. Call the DescribeImages operation to query the image information.

    If the product ID (ProductCode) of your image is not empty, your image is an Alibaba Cloud Marketplace image or a custom or shared image that derives from an Alibaba Cloud Marketplace image. For example, the product ID of your image is abcd000111, you can access the image at https://marketplace.alibabacloud.com/products/product category ID/abcd000111.

  2. Select the version and region of the image and purchase the image.

    An image purchased in a region can only be used in ECS instances in that region. In addition, you can only purchase one image at a time. If you need to create multiple ECS instances, you must purchase multiple images.

  3. After purchase, you can use the image to create an ECS instance or replace a system disk.

If I do not purchase an Alibaba Cloud Marketplace image or an image that derives from an Alibaba Cloud Marketplace image, will an error be reported when I call an ECS API operation to use the image to create an ECS instance or replace a system disk?

Yes. An error will be reported with the QuotaExceed.BuyImage error code.

My Auto Scaling (ESS) service is configured to automatically create a number of ECS instances from 10 to 100. What can I do with Alibaba Cloud Marketplace images to ensure that ECS instances are created to suit my computing needs?

If you need to automatically create n instances that use the same image, you must purchase n images from Alibaba Cloud Marketplace in advance.

Do Alibaba Cloud Marketplace images support bulk purchase?

No.

If a previously used Alibaba Cloud Marketplace image such as jxsc000010 or jxsc000019 no longer exists, what can I do to ensure that ECS instances are properly created based on the corresponding scaling configuration within an existing scaling group?

We recommend that you select a suitable replacement image from Alibaba Cloud Marketplace to ensure that ECS instances are properly created in your scaling group.

Can one product code support images of different regions?

Yes. The precondition is that the regions already support the image.

I bought 100 images with the same product code. Can I use them within any region?

Alibaba Cloud Marketplace images are region specific. If you want to use an image within a specific region, purchase the image within that region.

After I select I/O Optimized, I cannot select Alibaba Cloud Marketplace images when purchasing an ECS instance. What causes this and how can I resolve this issue?

The cause of and solution to this problem are as follows:
  • Problem description: When I purchase an ECS instance on the official Alibaba Cloud website, I cannot select any Alibaba Cloud Marketplace images.
  • Cause: If you select I/O Optimized when purchasing an ECS instance, you cannot select Alibaba Cloud Marketplace images.

    I/O optimized ECS instances provide better network capabilities between instances and disks compared with non-I/O optimized ECS instances, maximizing the storage performance of standard SSDs. However, not all images support I/O optimized instances because the related optimization operations involve the corresponding network, storage, and internal drivers.

  • Solution: When you purchase an I/O optimized instance, we recommend that you select an official standard image supported by the instance and then deploy the business environment.

If the problem persists, submit a ticket.

What are yearly, monthly, and weekly subscription Alibaba Cloud Marketplace images?

Yearly, monthly, or weekly subscription Alibaba Cloud Marketplace images are images that are purchased from Alibaba Cloud Marketplace and billed on a recurring basis. These images are developed and maintained by image providers, who are responsible for both pre-sales consultation and after-sales services. In this topic, these images are collectively referred to as subscription images.

In which ECS instance can I use a subscription image?

A subscription image can only be used in a subscription instance with the same billing cycle.

How do I purchase a subscription image? Can I purchase it separately?

You cannot purchase a subscription image separately.

You can purchase a subscription image in either of the following ways:
  • When you create an ECS instance, set Billing Method to Subscription, select an image from Alibaba Cloud Marketplace, and then set Duration.
    Note Then, you must pay for both the instance and image. The instance is created upon successful payment for both the image and instance.
  • If you want to use a subscription image in an existing subscription ECS instance, you can use this image to replace the operating system of the instance. In this case, you must set the image billing cycle the same as the instance billing cycle. For more information, see Replace the system disk (non-public image).
    Note In this case, you only need to pay for the image.

How do I pay for subscription images?

Subscription images require upfront payment, and its billing cycle must be the same as that of the subscription instance where the image is used.

Image prices are set by their providers.

Can I use a subscription image after it expires? How do I continue to use it?

When a subscription image expires, it cannot be used if it is not renewed in time.

You cannot renew a subscription image separately. If you want to continue using the image, you must renew the image with the corresponding ECS instance. You can resume use of the image after it is renewed.

After purchasing a subscription image, can I request a refund if I no longer want to use it?

The image provider will determine whether to make a refund. You can consult the image provider before your purchase the image.

What can I expect when a refund is made?

If a refund is available, the image provider will make the refund based on your usage.

Can a subscription image be converted to a pay-as-you-go image?

Subscription images cannot be converted to pay-as-you-go images. This function is currently under development for release in the future. Stay updated on the official Alibaba Cloud website.

Can I replace a subscription image with an image of another type or vice versa? How is the fee calculated?

Yes. You can replace images when you replace system disks of ECS instances. You can make the following replacements:
  • Replace an image of another type (such as public image, custom image, and shared image) with a subscription image. After the image is replaced, the system will calculate the actual cost based on the image cost and the remaining billing cycle of the ECS instance.
  • Replace a subscription image with an image of another type (such as public image, custom image, and shared image). If the image provider allows for refunds, a refund will be made based on your actual usage.
  • Replace subscription image A with subscription image B. After the image is replaced, if a refund is available for Image A, the refund will be made based on the refund policy. The actual cost of Image B will be calculated based on the image price and the remaining billing cycle of the ECS instance.

Where do I view and manage the subscription images I purchased?

You can log on to the ECS console. In the left-side navigation pane, choose Instances & Images > Images. Then, click the Image Market tab to view and manage the subscription images you purchased.

Is a fee charged for creating a custom image from a subscription image? How will created custom images be affected if their corresponding subscription images expire?

When you use a custom image created from a subscription image to create an instance or replace a system disk, you are re-ordering the subscription image on Alibaba Cloud Marketplace. Therefore, the custom image is not affected by whether the original subscription image expires.

Why I cannot select a Windows operating system for some ECS instances?

When you create an ECS instance from a Windows operating system, ensure that the instance memory is greater than or equal to 1 GiB. For ECS instances with less than 1 GiB of memory, you can only select Linux and Windows Server 1709 images.

Does Alibaba Cloud support Windows Server 2008 and Windows Server 2008 R2?

Support for Windows Server 2008 and Windows Server 2008 R2 was ended by Microsoft on January 14, 2020. Therefore, Alibaba Cloud does not provide technical support for ECS instances that use these operating systems. If you have an ECS instance that uses Windows Server 2008 or Windows Server 2008 R2, please change its operating system to Windows Server 2012 or a later version as soon as possible.

Is a fee charged for the operating system of an ECS instance?

The Windows Server and Red Hat operating systems of public images are charged. Their fees depend on instance types. Other public images are free of charge. For more information about the fees for other types of images, see Image types.

Can I install or upgrade my operating system?

No. You cannot install or upgrade your operating system. An ECS instance must use an image provided by Alibaba Cloud, which you cannot add or upgrade on your own. However, you can perform the following operations:

Do operating systems have a graphical interface?

Windows operating systems (except for the Windows Server Semi-Annual Channel instances) offer a management desktop. For information about how to use Windows Server Semi-Annual Channel operating systems, see Manage Windows Server Semi-Annual Channel images and instances.

Linux operating systems offer a command line interface. You can install a graphical desktop as needed.

How do I choose an operating system?

See Select an image.

Do public images come with the FTP service?

No. You must configure the FTP service on your own. For more information, see Build an FTP site on a Windows ECS instance and Build an FTP site on a Linux instance.

Which SUSE versions do Alibaba Cloud public images support?

Alibaba Cloud public images support SUSE versions. For more information, see Linux public images.

What service support is available for SUSE operating systems?

SUSE Linux Enterprise Server (SLES) operating systems sold on Alibaba Cloud Marketplace are synchronized with SUSE update sources regularly. For instances created from Alibaba Cloud SLES public images, the support for their operating systems is covered by the Alibaba Cloud enterprise-level support service. If you have purchased the enterprise-level support service and encounter a problem when using an SLES operation system, submit a ticket to contact Alibaba Cloud technical support personnel.

If an image has been manually created from an ECS instance, can I retrieve the instance data after it is released upon expiration?

Yes. You can retrieve instance data in either of the following ways:
  • Create a new instance from the previously created image. For more information, see Create an instance by using a custom image.
  • Use the previously created image to replace the system disk of the current instance. For more information, see Replace the system disk (non-public image).
    Notice When you replace a system disk, note the following items:
    • All current system disk data will be lost, and the system disk will be restored to the state of the image.
    • The image must be in the same region as the current instance.

I have an ECS instance and want to create another ECS instance from the image of the current ECS instance. What can I do?

You can create a custom image from the current ECS instance and then use the custom image to create a new ECS instance. For more information, see Create a custom image by using an instance and Create an instance by using a custom image.

I have purchased an ECS instance. How do I restore my shared image to the newly purchased instance?

Make sure that you have shared the image to the account of the newly purchased instance, and use either of the following methods as needed:
  • If the shared image and the instance reside within the same region, replace the system disk of the instance and select the shared image for the new system disk. For more information, see Replace the system disk (non-public image).
  • If the shared image and the instance do not reside within the same region, copy the image to the region where the instance is located. Then replace the instance system disk, and select this image for the new system disk. For more information, see Copy custom images and Replace the system disk (non-public image).
Notice The following risks are associated with replacing the system disk of an instance:
  • The original system disk will be released. We recommend that you create a snapshot to back up your data in advance.
  • Replacing the system disk requires stopping the instance, which can interrupt services.
  • After replacing the system disk, you must re-deploy the service environment on the new system disk. Your services may be interrupted for an extended period of time.
  • Replacing a system disk will re-allocate a system disk to your instance, and the disk ID will change. Snapshots created from the original system disk cannot be used to roll back the new system disk.

The operating system of my instance is Windows Server 2008 R2 Enterprise Edition. I am prompted with a message indicating that the operating system is not genuine. What can I do?

You can perform the following steps:
  1. Activate the Windows operating system. For more information, see How to activate ECS Windows in a VPC environment.
    Note Disable the firewall in your instance before you perform this step.
  2. Log on to the ECS console.
  3. Connect to your instance by using the remote connection feature in the ECS console. Then, download and install the patch to your instance. For more information, see How to solve authentication errors caused by CredSSP encryption oracle remediation when connecting to Window instances. As of May 2018, Microsoft has updated the patches and authentication request methods related to the Credential Security Support Provider Protocol (CredSSP).

I have multiple Alibaba Cloud accounts. I want to transfer an instance from Account A to Account B or use an image to migrate the environment and applications of an instance under Account A to an instance under Account B. What can I do?

You can perform the following steps:
  1. Create a custom image from the instance under Account A. For more information, see Create a custom image by using an instance.
  2. Share the image to Account B. For more information, see Share or unshare custom images.
  3. Create an instance under Account B from the shared image. For more information, see Create an instance by using a custom image.

How do I migrate data between ECS instances?

Perform the following steps to migrate data from one ECS instance to another:
  1. Create a custom image from the source ECS instance.
  2. Copy or share the custom image.
    • If the source and destination instances are located in the same region and belong to the same account, go to the next step.
    • If the source and destination instances are located in different regions but belong to the same account, copy the image to the region where the destination instance is located. For more information, see Copy custom images.
    • If the source and destination instances are located in the same region but belong to different accounts, share the custom image to the account of the destination instance. For more information, see Share or unshare custom images.
    • If the source and destination instances are located in different regions and belong to different accounts, copy the image to the region where the destination instance is located, and share the image to the account of the destination instance. For more information, see Copy custom images and Share or unshare custom images.
  3. Use the shared image to create a new ECS instance or replace the image of the destination instance. For more information, see Create an instance by using a custom image or Change the operating system.
    Note If you want to replace the image of the destination instance, you must ensure that the original image does not contain any data disk snapshots.

If the preceding steps are not applicable, see Migrate your instance within Alibaba Cloud ECS for more information about how to migrate data between ECS instances.

Can ECS instances in different VPCs communicate with each other?

Express Connect and Cloud Enterprise Network (CEN) can be used to allow VPCs to connect to each other. For more information, see Interconnect two VPCs under the same account and Connect networks that belong to the same account but different regions. ECS instances in interconnected VPCs can then communicate with each other.

How do I handle a CentOS DNS resolution timeout?

The CentOS DNS resolution timeout problem is analyzed and fixed as follows:
  • Cause

    The DNS resolution mechanism of CentOS 6 and CentOS 7 has changed. CentOS 6 or CentOS 7 instances created before February 22, 2017 or created from custom images that were created before February 22, 2017 may encounter a DNS resolution timeout.

  • Solution
    Perform the following steps to fix this problem:
    1. Download the fix_dns.sh script.
    2. Place the downloaded script in the /tmp directory of the CentOS system.
    3. Run the bash /tmp/fix_dns.sh command to execute the script.
  • Script role

    The script determines whether the /etc/resolv.conf file contains the options>single-request-reopen configuration. For more information, see resolv.conf - resolver configuration file.

    The DNS resolution mechanism of CentOS 6 and CentOS 7 uses the same 5-tuple to send IPv4 and IPv6 DNS requests, for which purpose the single-request-reopen option must be added. After the option is added, when two requests from the same port are handled, the resolver closes the socket after sending the first request and opens a new socket before sending the second request. The option will take effect immediately after being added. You do not need to restart the instance.

  • Script logic
    1. Determines whether the instance operating system is CentOS.
      • If no (for example, the operating system is Ubuntu or Debian), the script stops working.
      • If yes, the script continues working.
    2. In the /etc/resolv.conf file, query the options configuration.
      • If the options configuration is unavailable:
        The Alibaba Cloud options configuration (options timeout:2 attempts:3 rotate single-request-reopen) is used by default.
      • If the options configuration is available:
        • If the single-request-reopen option does not exist, append this option to the options configuration.
        • If the single-request-reopen option exists, the script stops working and the DNS nameserver configuration does not change.

Why does ECS disable virtual memory and leave Swap partitions unconfigured by default?

When physical memory is insufficient, the memory manager temporarily stores the memory data that has been inactive for an extended period of time to a Swap partition or virtual memory file. This mechanism helps increase the available memory.

However, if the memory usage is already high and I/O performance is poor, the mechanism will decrease the available memory instead. Alibaba Cloud ECS disks use distributed file systems for storage and provide multiple strongly consistent replicas for each piece of data. This mechanism ensures the security of user data but deteriorates the storage and I/O performance of local disks by tripling the number of I/O operations.

Because of this, virtual memory is not enabled for Windows, and Swap partitions are not configured for Linux by default to avoid further decreasing I/O performance when system resources are insufficient.

How do I enable the kdump service in a public image provided by Alibaba Cloud?

The kdump service is disabled by default in Alibaba Cloud public images. If you want your instance to generate a core file when the instance is down so that you can analyze the downtime cause based on the file, perform the following procedure to enable the kdump service. This procedure uses the CentOS 7.2 public image as an example.
  1. Configure the directory in which to generate the core file.
    1. Run the vim /etc/kdump.conf command to open the kdump profile.
    2. Run the path command to configure the directory in which to generate the core file. In this example, the directory is /var/crash, and the following path command is used:
      path /var/crash
    3. Save and close the /etc/kdump.conf file.
  2. Enable the kdump service.
    Based on the operating system, use either of the following methods to enable the kdump service. In this example, the kdump service in CentOS 7.2 is enabled with method 1.
    • Method 1: Run the following commands to enable the kdump service:
      systemctl enable kdump.service
      systemctl start kdump.service
    • Method 2: Run the following commands to enable the kdump service:
      chkconfig kdump on
      service kdump start
  3. Run the following command to simulate the scenario where the instance is down:
    echo c > /proc/sysrq-trigger
    Note After the command is executed, the instance is disconnected from the network. You must reconnect the instance to the network to perform the subsequent operations.
  4. Analyze the core file.
    1. Run the following command to install the Crash Analysis tool:
      yum install crash
    2. Download the debug-info installation package.
      Run the uname -r command to view the operating system kernel version and download the debug-info installation package that matches the kernel version.
      • kernel-debuginfo-common-x86_64-<kernel version>.rpm
      • kernel-debuginfo-<kernel version>.rpm
      In this example, the kernel version is 3.10.0-514.26.2.el7.x86_64. The following download commands are used:
      wget http://debuginfo.centos.org/7/x86_64/kernel-debuginfo-common-x86_64-3.10.0-514.26.2.el7.x86_64.rpm
      wget http://debuginfo.centos.org/7/x86_64/kernel-debuginfo-3.10.0-514.26.2.el7.x86_64.rpm
    3. Run the following commands to install the debug-info package:
      rpm -ivh kernel-debuginfo-common-x86_64-3.10.0-514.26.2.el7.x86_64.rpm
      rpm -ivh kernel-debuginfo-3.10.0-514.26.2.el7.x86_64.rpm
    4. Run the following commands to use the Crash Analysis tool to analyze the core file:
      dd <core file directory>
      crash /usr/lib/debug/lib/modules/<kernel version>/vmlinux vmcore
      In this example, the core file directory is /var/crash/127.0.0.1-2019-07-08-15:52:25, and the kernel version is 3.10.0-514.26.2.el7.x86_64. The following commands are used:
      cd /var/crash/127.0.0.1-2019-07-08-15:52:25
      crash /usr/lib/debug/lib/modules/3.10.0-514.26.2.el7.x86_64/vmlinux vmcore

How do I enable or disable the Meltdown and Spectre patches for Linux images?

For information about security vulnerabilities and public images involved as well as how to enable or disable security vulnerability patches, see How do I enable or disable the Meltdown and Spectre patches for Linux images?.

After I use an ECS instance without restarting it for an extended period of time that exceeds the specified threshold, the instance is disconnected from the network, the network is no longer available, or the public or private IP address of the instance cannot be pinged. What can I do?

For more information about the cause of and solution to this issue, see Troubleshoot IP address faults in CentOS 7 instances and Windows instances.

The “UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY” error is returned when an ECS instance starts. What can I do?

This indicates that a file system error occurs due to data loss in the memory of the ECS instance, which may be caused by conditions such as poweroff. For more information about the problem and solution, see How to solve the “UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY” error returned.

How do I upgrade Red Hat Enterprise Linux (RHEL) 7 to RHEL 8?

For more information, see Upgrading to RHEL 8.