Aliyun How to create a custom mirror

　　Aliyun How to create a custom mirror

A custom mirror is a user who is running an ECS instance of a cloud server effectively. With the custom mirrors you have created, you can help you to open multiple instances of the cloud server ECS that have completely copied the same operating system and environment data, to meet your flexible expansion of the business needs.

A custom mirror is a snapshot based on the cloud server system disk at a certain point in time. The simultaneous deployment of a cloud server ECS instance can be either the same or different.

Description

One account can create up to 30 custom mirrors.

Created custom mirrors cannot be used across regions.

The operating system can be replaced by a cloud server that is open by custom mirroring. The original custom mirror can also continue to be used after the system has been replaced. See replacing system disks.

A cloud server that uses custom mirroring can upgrade CPU, memory, bandwidth, hard disk, and so on.

The custom mirroring feature is not restricted by the sale mode, that is, it does not distinguish between package year monthly and per-volume payment. A custom mirror of a yearly monthly cloud server that can be used to open a pay-as-you-go cloud server and vice versa.

When the cloud server that is used to create a custom mirror expires or the data is released (that is, the system disk used for the snapshot expires or is released), the custom mirrors that are created are not affected, and the cloud servers that are opened using custom mirrors are unaffected. However, automatic snapshots are purged as the cloud server is released.

Operation Steps

Log on to the Cloud Server Management Console.

Click the snapshot in the left navigation. You can see the snapshot list. Then select the region at the top of the page.

Select a disk property as a snapshot of the system disk. Click to create a custom mirror. A data disk cannot be used to create a custom mirror.

In the dialog box that pops up, you can see the ID of the snapshot. Enter a name and description for the custom mirror. Click Create.

Custom mirror creation succeeded. You can click a mirror in the left navigation and then view the mirrors that were created.

Linux Considerations

When creating a custom mirror using a Linux system, be careful not to load the data disk's information in the/etc/fstab file, otherwise the instance created using the mirror cannot start.

It is highly recommended that you unmount the data disks under Linux before making a custom mirror, and then take a snapshot and create a custom mirror, or it may cause a cloud server created with that custom mirror to fail to start and use.

Kernel and operating system versions please do not upgrade at will.

Do not adjust system disk partitions, only a single root partition is currently supported

Please check that the system disk uses the remaining space to ensure that the system disk is not filled

Do not modify key system files such as/sbin,/bin,/lib directory, etc.

How do I umount and delete the data in disk table?

Assuming/dev/hda5 is already mounted on the/MNT/HDA5, the mounted file system can be uninstalled with the following three commands:

"' Umount/dev/hda5umount/mnt/hda5umount/dev/hda5/mnt/hda5 '"

/etc/fstab is a more important configuration file under Linux, and it contains detailed information about the system's mounting of file systems and storage devices at startup. If you do not want to mount the specified partition when the VM is started, you need to delete the corresponding row in the file, delete the following statement to disconnect Xvdb1/dev/xvdb1/leejd ext4 defaults 0 0 at startup

How do I confirm that the data disk has been uninstalled and can start creating a custom mirror?

You need to confirm that the Fstab file contains the corresponding automatic Mount data disk partition statement line has been deleted. Use the Mount command to view the mount information for all devices, and verify that the execution results do not contain the corresponding data disk partition information.

Related configuration Files

If you want to create a custom mirror for an instance of Linux, some profiles cannot be manually modified, which may cause the system to fail to start. As shown in the following table.

configuration file	configuration Note	Modify the risk for this profile
/etc/issue ,/etc/-release,/etc/*_version	system release information configuration file	" "" "" the/etc/issue* will cause the system distribution to not be recognized properly, causing system creation to fail.
/boot/grub/menu.lst,/boot/grub/grub.conf	system boot Boot configuration file	modify/boot/grub/menu.lst causes the kernel to not load properly, causing the system to fail to start.
/etc/fstab	system boot mount points Zone configuration file
/etc/shadow	system password-related Configuration file
/etc/selinux/config	system security Policy configuration The file	modify/etc/selinux/config to open selinux cause the system to fail to start.