How We Migrated a Restaurant’s Legacy VMware Infrastructure to UCloud Seamlessly

This article summarizes how a team helped a restaurant client migrate its on‑premises VMware environment to the UCloud public cloud, saving operational manpower and costs while providing elastic scaling for future business growth.

Background

The client wanted to move its services from a self‑built virtualized data center to UCloud, replacing an old VMware setup with a public‑cloud architecture. Their requirements were:

Migration should not affect existing services.

Eliminate outdated equipment and reduce unnecessary expenses.

Reduce maintenance manpower and operational pressure.

Complete the migration quickly without disrupting marketing or innovation activities.

Migration Assessment

Feasibility analysis identified several challenges:

Many operating systems were old, primarily Windows Server versions.

Business systems lacked deployment documentation or source code, making reconstruction impossible.

Large volumes of data, especially databases and backups, needed migration.

Because existing migration tools mainly support modern OSes like CentOS and Ubuntu, the team opted for an image‑based migration approach.

Migration Plan

The overall migration strategy consisted of two directions:

2.1 Public‑bandwidth Transfer

Preconditions:

Sufficient public bandwidth without impacting production.

Data sensitivity low enough to allow public transfer.

Data volume preferably under 10 TB.

2.2 Offline Disk Copy

This method uses portable disk cabinets for image transfer, offering high data security (RAID‑5), fast transfer speeds (USB 3.0 up to 500 MB/s), and the ability to mount physical servers to bridge on‑premises and cloud networks.

Given the large data volume, the team chose the offline disk‑copy method.

Migration Details

Migration Flowchart

Initial steps:

Disable Windows Group Policy on the guest system.

Uninstall VMware Tools.

Turn off antivirus software.

Shut down the virtual machine.

Create a physical cloud server and mount the portable disk cabinet to transfer system and data disk images. Use qemu-nbd to expose the images as block devices, then convert and inject VirtIO drivers.

3.1 Prepare Original IDC VMware Environment

(1) Connect vSphere client to vCenter. (2) Export VM images as OVF or VMDK; if offline export is not possible, clone to VMDK.

3.2 Prepare Transfer Server Environment

(1) Install KVM on a CentOS 7 host with hardware virtualization enabled and sufficient disk space. (2) Install virt-v2v for converting legacy Windows systems (e.g., Windows 2000, Server 2003/2008). (3) Install VirtIO drivers on the host to improve I/O performance. (4) Install ntfs-3g for NTFS support on Linux. (5) Compile and install NBD for remote block device access.

3.3 Image Conversion and VirtIO Driver Injection

Run the following commands to convert disks and inject drivers:

# export LIBGUESTFS_BACKEND=direct
# virt-v2v -i vmx server2003.vmx -of qcow2 -o qemu -os ./

3.4 Create Temporary System and Data Disks via API

Use internal APIs to create two temporary cloud disks that serve as the system and data disks for the migration. (Reference: https://github.com/ucloud)

3.5 Remote Mount and Disk Copy

Mount the portable cabinet’s disks on the transfer server using qemu-nbd and qemu-img, then copy them to the newly created cloud disks, avoiding public bandwidth and object storage.

# qemu-nbd -r -t -v -f qcow2 -p 5000 web-sdc.qcow2
# qemu-img convert nbd://10.23.xx.xx:5000 /dev/vdc

3.6 Create Cloud VM and Attach Data Disk

After syncing system and data disks, use APIs to create a cloud VM with the system disk and attach the data disk. UCloud provides automation scripts for this process.

Experience

The migration revealed several constraints for future reference:

Windows 7 and Windows Server 2008 R2 require SHA‑2 certificate support.

For consistency, consider disabling business I/O writes during migration.

Uninstall antivirus software.

Uninstall virtualization platform tools.

Value

The solution enables traditional industries to quickly adopt cloud infrastructure, dramatically reducing physical server maintenance labor and costs. It also provides elastic scaling for future business expansion without additional hardware procurement, while allowing legacy systems to continue operating.