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Reinstall and configuration changes

Reinstall an instance's operating system, and how to handle configuration changes.

4 min read Updated Oct 6, 2026

This page explains how to reinstall a cloud server's operating system, and what to do when you need to change an instance's resources.

Reinstall the operating system

Reinstalling recreates the system disk from the image you choose. Use it when the system is broken, when you want a different distribution, or when you want a clean system.

Before you reinstall

  • All data on the system disk is erased, including website files, databases, configuration and user accounts. Copy anything important to a data disk or somewhere outside the instance first.
  • Data disks are not touched, but the new system will not keep the old system's mount configuration.
  • The instance must have the status 运行中 (Running) with no other task in progress. You cannot reinstall while it is 创建中 (Creating), 重建中 (Rebuilding), 迁移中 (Migrating) and so on.

Steps

  1. Go to 云服务器 > 我的实例 (Cloud Servers > My Instances) and click 管理 (Manage) on the instance to open its detail page.
  2. Click 重装系统 (Reinstall OS) at the top of the page.
  3. In the dialog, check 当前系统 (Current OS), then choose an image under 新系统镜像 (New image); you can type to search. The images available depend on the product you bought. You can also pick the same image you have now.
  4. Set the 新密码 (New password):
    • A random password is filled in when the dialog opens. Click 生成随机密码 (Generate random password) for another one, or type your own.
    • If you clear the field, the instance keeps its existing password after the reinstall.
  5. Read the 危险操作 (Dangerous operation) notice and click OK when you are sure.
Warning

The instance is forcibly powered off before the reinstall starts, and a reinstall cannot be undone. Back up the data on the system disk beforehand.

After you submit, the status changes to 重建中 (Rebuilding). The process usually takes 5–30 minutes. When it finishes the status returns to 运行中 and the new password appears under 基础信息 > 初始密码 (Basic info > Initial password).

After reinstalling

Clear the old SSH host fingerprint. The instance's host key changes after a reinstall, so your SSH client will warn that the fingerprint does not match. Remove the old entry on your computer and reconnect:

bash
ssh-keygen -R 203.0.113.10
ssh root@203.0.113.10

Remount data disks. If the instance has data disks, mount them again in the new system. On Linux:

bash
lsblk                         # find the data disk, e.g. /dev/sdb or /dev/vdb
blkid /dev/sdb1               # get the partition UUID
mkdir -p /data
mount /dev/sdb1 /data
# Once it looks right, add it to /etc/fstab so it mounts at boot:
echo 'UUID=<UUID from above> /data ext4 defaults,nofail 0 2' >> /etc/fstab
Note

If the data disk already has a partition and file system, do not run mkfs on it, or its data will be lost.

Reconfigure additional IPs and the firewall. Settings made inside the OS, such as additional IPs and firewall rules, need to be set up again. See Networking and public IPs.

View the instance's resources and disks

The 基础信息 (Basic info) card on the detail page shows the instance's current CPU, 内存 (Memory), 带宽 (Bandwidth), 流量 (Traffic) allowance and 系统 (OS image).

The 硬盘管理 (Disks) card lists all of the instance's disks. Each one is labelled 系统盘 (System disk) or 数据盘 (Data disk) with its device name and capacity; expand it to see 设备名 (Device), 容量 (Capacity), 驱动类型 (Driver) and 缓存模式 (Cache mode).

Change resources

The console does not currently offer self-service plan upgrades or downgrades. CPU, memory, bandwidth, disk capacity and number of IPs are those of the plan you chose at purchase.

If you need a change:

  • More resources: contact support to have the configuration adjusted, or buy a new, larger instance, migrate your data, and then ask support to release the old one.
  • A different location or product: buy a new instance under the target product and migrate your data.

For migrating data, see the rsync and mysqldump examples in Snapshots and backups. Sync data to the new instance first, confirm your services work, and then switch DNS.

Troubleshooting

"当前状态不允许重装" (Reinstall not allowed in current state) The instance is not 运行中. Wait for the current operation to finish. If the instance shows 已暂停 (Suspended) or 流量限制 (Traffic limited), contact support.

"队列正在执行中无法继续操作" (A queued task is still running) Another task, such as a snapshot or a previous reinstall, is still running. Try again shortly.

Cannot log in with the new password after reinstalling Open VNC first to confirm the system has finished its first boot. Windows images take longer to boot the first time, so give it a few more minutes.

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