Reset a simple application server - Simple Application Server

Resetting a simple application server reinstalls its applications or operating system, returning the server to a clean state. Choose between keeping the current system or replacing it with a different image.

Warning

Resetting deletes all data on the system disk. Back up your data before you proceed.

Prerequisites

The server must be in the Running or Stopped state.

Potential impacts

Resource	Impact
System disk	All data is deleted.
Data disk	Data is preserved. You may need to remount or reconfigure the disk depending on the reset method. See Data disk behavior.
Snapshots	Retained, but cannot roll the disk back to its pre-reset state.
Key pair	Automatically unbound during the reset. Rebind after the reset completes. See Attach a key pair.
Monitoring	CloudMonitor may stop working. Reinstall the agent by connecting to the server or by using Command Assistant.

Data disk behavior by reset method

Reset method	OS change	Action required
Reset current system	Linux	Remount the data disk manually. Automatic mount configurations are lost.
Reset current system	Windows	None.
Replace image (same OS family)	Linux to Linux	Remount the data disk.
Replace image (same OS family)	Windows to Windows	None.
Replace image (cross-OS)	Linux to Windows or vice versa	The new OS cannot recognize the data disk file system. Install compatibility software or re-initialize the disk (erases all data). See Handle cross-OS data disk compatibility.

Important

If you reset using a custom image that contains a data disk, make sure no business dependency exists between the original system disk and the data disk. Operations from the new system disk to the new data disk may cause exceptions.

Limitations

Servers created from a custom image that includes a data disk snapshot cannot be reset.
For servers in regions outside the Chinese mainland, switching between Windows and Linux is not supported. Reset only within the same OS family.
When resetting with a custom image:
- The image must be in the same region as the server.
- Images that contain a data disk snapshot cannot be used.
- Images created from the current server cannot be used.
- The image system disk size must not exceed the server system disk size. If it does, upgrade the server configurations first.

Note

To restore data after a reset, use a custom image created before the reset to create a new server.

Procedure

Log on to the Simple Application Server console.
In the left-side navigation pane, click Servers.
Find the target server and choose More > Server Resetting.
Note
You can also click the server ID to open the details page, then click Server Resetting in the upper-right corner or below Image Information in the Basic Information section.

Select a resetting mode.

Reset the current system

Reinstall the current operating system without changing the image.

Parameter	Description
Select a server resetting mode	Select Reset Current System.
Advanced Configuration > Logon Credential	Custom Password: Enter and confirm a password. Key Pair: Select an existing key pair. Configure after Resetting (default): Set a password after the reset completes.

Replace the image

Replace the current image with an application image, OS image, or custom image.

Parameter	Description
Select a server resetting mode	Select Replace with Another Image, then choose an image from the Application Images, OS Images, or Custom Images tab.
Advanced Configuration > Logon Credential	Custom Password: Enter and confirm a password. Key Pair: Select an existing key pair. Configure after Resetting (default): Set a password after the reset completes.

Important

If a key pair was bound to the server, it is automatically unbound during the reset. Rebind the key pair after the reset completes. See Attach a key pair.

Click Confirm Resetting.
Read the confirmation message and click OK.
The server status changes from Resetting to Running when the reset completes. If the reset fails, check the Limitations section. If the requirements are not met, the server cannot be reset. If all requirements are met, submit a ticket for technical support.

Next steps

Redeploy the environment

After the reset, the server runs a clean OS. Reinstall required software, configure package repositories (APT or YUM), and set up environment variables.

Recover system disk data

The original system disk is released and all data is deleted. To recover data, create a pay-as-you-go disk from a snapshot and attach it to the server. Release the disk promptly to avoid unnecessary charges. See Use a snapshot of the original system disk to restore data after the system disk of an ECS instance is replaced.

Handle cross-OS data disk compatibility

When you switch between Windows and Linux, the new OS cannot read the data disk file system.

Linux to Windows:

The Windows OS cannot recognize Ext3, Ext4, or XFS file systems on the data disk.

No important data on the disk: Re-initialize and format for Windows. See Re-initialize a data disk and Initialize a data disk on a Windows instance.
Important data on the disk: Install Ext2Read or Ext2Fsd to read Ext3, Ext4, or XFS file systems on Windows.

Windows to Linux:

The Linux OS cannot recognize the NTFS file system on the data disk.

No important data on the disk: Re-initialize and format for Linux. See Re-initialize a data disk and Initialize a data disk (Linux).
Important data on the disk: Install ntfsprogs to read the NTFS file system on Linux:
```
yum -y install ntfs-3g
mount -t ntfs-3g <Partition name of the data disk> <Mount directory>
```
Note
Replace <Partition name of the data disk> and <Mount directory> with your actual values.

For more information, see How do I move an NTFS disk between a Linux instance and a Windows instance?