Create and manage image

An image is a template that includes the operating system, applications, and configuration settings required to run a virtual machine.
You can start an instance by selecting the required operating system and application as an image according to your purpose.

View image list and basic information

You can view the list of images in use and information about each image.

1. Go to Compute > Beyond Compute Service > Virtual Machine in the KakaoCloud console.

2. In the Image menu, select the target image. View image list

   Category	Description
   Default image	Image provided by KakaoCloud by default
   Custom image	Image created directly by the user - You can edit the image name and description, and delete the image

info

Among the provided default images, images based on the Windows operating system are not eligible for free credits.

Create custom image

You can create an image from the current state of an instance. This custom image can then be used when creating an instance.

info

• Only the root volume where the operating system is installed can be created as an image. To back up additional volumes, use the Snapshot feature.
• If you create a custom image through Create image from the created VM instance, the operation may fail depending on the size of the attached root volume. When creating a custom image, a target volume size of 1 TB or less attached to the instance is recommended.

1. Go to Compute > Beyond Compute Service > Virtual Machine in the KakaoCloud console.
2. In the Instance menu, select [⋮] button > Create image.
3. In the pop-up window, enter the information, then click the [Create] button.

Create instance with custom image

You can create an instance using the information saved in a custom image.

1. Go to Compute > Beyond Compute Service > Virtual Machine in the KakaoCloud console.
2. In the Image menu, select Custom image.
3. Select Create instance on the right side of the image list.
4. Enter the required information, then click the [Create] button.

Modify custom image

You can modify the information of a custom image.

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For images shared from another project, only the creator of the image can modify it.

1. Go to Compute > Beyond Compute Service > Virtual Machine in the KakaoCloud console.
2. In the Image menu, select Custom image.
3. Select [⋮] button of the image to modify > Edit image.
4. In the pop-up window, modify the information, then click the [Save] button.

Share custom image

You can share an image created by the user with another project that the user belongs to.

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• Only the user who first created the image can share or unshare the image.
  
• Members of the project that received the shared image will see the [Shared] icon next to the shared image.

1. Go to Compute > Beyond Compute Service > Virtual Machine in the KakaoCloud console.

2. In the Image menu, select Custom image.

3. Select [⋮] button of the image to share > Share image.

4. In the pop-up window, select the project to share with, then click the [Share] button.

   Share image

Delete custom image

You can delete an image that is no longer in use.

info

• Only custom images created by you can be deleted.
• For images shared from another project, only the creator of the image can delete them.

1. Go to Compute > Beyond Compute Service > Virtual Machine in the KakaoCloud console.
2. In the Image menu, select Custom image.
3. Select [⋮] button of the image to delete > Delete image.
4. In the pop-up window, enter the confirmation text, then click the [Delete] button.

Change root volume partition table format

For instances based on certain operating systems, the default partition table format of the root volume disk is the MBR (Master Boot Record) partitioning scheme. The MBR partitioning scheme supports only up to four partitions and works only on disks up to 2.0 TB, whereas the GPT partitioning scheme has no such limitations on partition count or volume size.

KakaoCloud provides the cloud images of each operating system as-is without configuration changes. You can change the root volume partition table format of instances based on CentOS, CentOS Stream, and Rocky Linux OS currently provided by KakaoCloud from MBR to GPT (GUID Partition Table).

The partition table format and file system type by operating system provided by KakaoCloud are as follows.

OS name	Version	Root volume partition table format
Ubuntu	20.04	GPT
Ubuntu	22.04	GPT
Ubuntu	24.04	GPT
CentOS Stream	9	MBR
Rocky Linux	8.10	MBR
Rocky Linux	9.4	MBR
Alma Linux	8.10	GPT
Alma Linux	9.4	GPT
Windows	2019	MBR
Windows	2022	MBR

Procedure

The following describes how to change the disk partition table format of a CentOS instance from MBR to GPT.
This procedure is based on the CentOS Stream 8 image currently provided by KakaoCloud.

caution

If you change the partition table format of a volume already in use, pay attention to data preservation and back up the data before making the change.

1. Check the current disk information with the lsblk command.

   Klsblk command

   [root@centos ~]$ sudo fdisk -l
   
   Disk /dev/vda: 10.7 GB, 10737418240 bytes, 20971520 sectors
   Units = sectors of 1 * 512 = 512 bytes
   Sector size (logical/physical): 512 bytes / 512 bytes
   I/O size (minimum/optimal): 512 bytes / 512 bytes
   Disk label type: dos
   Disk identifier: 0x0009b542
   
   Device Boot      Start         End      Blocks   Id  System
   /dev/vda1   *        2048    20971486    10484719+  83  Linux

2. Check the current partition table information of the disk with the gdisk command.

   gdisk command

      [root@centos ~]$ sudo gdisk -l /dev/vda
      GPT fdisk (gdisk) version 0.8.10
   
      Partition table scan:
      MBR: MBR only
      BSD: not present
      APM: not present
      GPT: not present
   
      ***************************************************************
      Found invalid GPT and valid MBR; converting MBR to GPT format
      in memory.
      ***************************************************************
   
      Disk /dev/vda: 20971520 sectors, 10.0 GiB
      Logical sector size: 512 bytes
      Disk identifier (GUID): 79C4C601-BF62-45E4-97F8-AB21F158EED7
      Partition table holds up to 128 entries
      First usable sector is 34, last usable sector is 20971486
      Partitions will be aligned on 2048-sector boundaries
      Total free space is 2014 sectors (1007.0 KiB)
   
      Number  Start (sector)    End (sector)  Size       Code  Name
        1            2048        20971486   10.0 GiB    8300  Linux filesystem

3. Change the partition table from MBR to GPT with the gdisk command.

   • Because GPT requires a boot partition, create that partition.
   • Set the boot partition to first sector 34 and last sector 2047, and select the partition code as ef02.

4. Install grub on the new boot partition.

   Install grub

   #Recognize new partition
   [root@centos ~]$ sudo partprobe
   #Install GRUB
   [root@centos ~]$ sudo grub2-install /dev/vda
   Installing for i386-pc platform.
   Installation finished. No error reported.

5. Run the reboot command to apply the changes.

   Reboot command

   [root@centos ~]$ sudo reboot

6. Check whether the disk partition table format has been changed correctly with the lsblk command.

   Check format change

   [root@centos ~]$ sudo fdisk -l
   WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion.
   Disk /dev/vda: 3221.2 GB, 3221225472000 bytes, 6291456000 sectors
   Units = sectors of 1 * 512 = 512 bytes
   Sector size (logical/physical): 512 bytes / 512 bytes
   I/O size (minimum/optimal): 512 bytes / 512 bytes
   Disk label type: gpt
   Disk identifier: D9C42684-E18C-4B8F-9388-C2F2CDC093ED
   #         Start          End    Size  Type            Name
   1         2048   6291455965      3T  Linux filesyste Linux filesystem
   2           34         2047   1007K  BIOS boot       BIOS boot partition