- `availability_zone` (string) - This is the UCloud availability zone where UHost instance is located. such as: `cn-bj2-02`. You may refer to [list of availability_zone](https://docs.ucloud.cn/api/summary/regionlist) - `source_image_id` (string) - This is the ID of base image which you want to create your customized images with. - `instance_type` (string) - The type of UHost instance. You may refer to [list of instance type](https://docs.ucloud.cn/compute/terraform/specification/instance)