\~>**Note:** The bulider doesn't support Windows images for now and only supports CentoOS and ubuntu images via SSH anthentication with `ssh_username` (Required) and `ssh_password` (Optional). The `ssh_username` must be `root` for CentOS images and `ubuntu` for Ubuntu images. The `ssh_password` may contain 8-30 characters, and must be consisted with at least 2 items out of the capital letters, lower case letters, numbers and special characters. The special characters include <code>`()~!@#$%^&*-+=_|{}\[]:;'<>,.?/</code>.
-`public_key` - (string) This is the UCloud public key. It must be provided, but it can also be sourced from the `UCLOUD_PUBLIC_KEY` environment variable.
-`private_key` - (string) This is the UCloud private key. It must be provided, but it can also be sourced from the `UCLOUD_PRIVATE_KEY` environment variable.
-`project_id` - (string) This is the UCloud project id. It must be provided, but it can also be sourced from the `UCLOUD_PROJECT_ID` environment variables.
-`region` - (string) This is the UCloud region. It must be provided, but it can also be sourced from the `UCLOUD_REGION` environment variables.
-`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)
-`instance_type` - (string) The type of UHost instance. You may refer to [list of instance type](https://docs.ucloud.cn/compute/terraform/specification/instance)
-`image_name` - (string) The name of the user-defined image, which contains 1-63 characters and only support Chinese, English, numbers, '-_,.:[]'.
-`use_ssh_private_ip` - (boolean) - If this value is true, packer will connect to the created UHost instance via a private ip instead of allocating an EIP (elastic public ip).(Default: `false`).
\~>**Note:** By default (`use_ssh_private_ip` is `false`), the launched uhost instance will be connecting with extranet by bounding with an EIP (elastic public ip) automatically, which bandwidth is 30 Mb by default and paid by traffic.
-`internet_charge_mode` -(Optional) The EIP (elastic public ip) charge mode associated to UHost instance. Possible values are: `traffic` as pay by traffic, `bandwidth` as pay by bandwidth. (Default: `traffic`).
-`vpc_id` - (string) The ID of VPC linked to the UHost instance. If not defined `vpc_id`, the instance will use the default VPC in the current region.
-`subnet_id` - (string) The ID of subnet under VPC. If `vpc_id` is defined, the `subnet_id` is mandatory required. If `vpc_id` and `subnet_id` are not defined, the instance will use the default subnet in the current region.
-`image_copy_to_mappings` (array of copied image mappings) - The array of mappings regarding the copied images to the destination regions and projects.
-`project_id` (string) - The destination project id, where copying image in.
\~>**Note:** Source image may be deprecated after a while, you can use the tools like `UCloud CLI` to run `ucloud image list` to find one that exists.