Constraints

Migration is only supported for public images for ECSs listed in the Supported Instance Types.
During the OS migration, RPM packages need to be uninstalled, installed, and updated. As a result, the OS may restart unexpectedly. Back up the system disk before the OS migration. For details, see Creating a Cloud Server Backup.
The remaining OS memory should be greater than 128 MB, the remaining system disk space (required for running the migration tool) be greater than 5 GB, and the available space of the boot partition be greater than 200 MB.
The name of a customized RPM package must be different from that of the OS RPM package. Otherwise, the custom RPM package will be deleted by the migration tool during the migration.
After the OS migration, the system disk type cannot be changed.
During OS migration, certain conflicting packages are generated in the system to be migrated. They will be automatically deleted after the OS migration. For details about the conflicting packages, see Conflicting Packages.
DNF is used during system migration. If the version of the original DNF is too early, the upgrade will be affected. You can uninstall DNF from the original OS.