$ tree
.
└── terraform
    └── alibaba
        ├── README.md
        ├── main.tf //AlibabaCloudのリソースを定義
        ├── staging
        │   ├── backend.tf //バックエンドを指定
        │   └── terraform.tfvars //variables.tfで定義した変数の値を指定
        └── variables.tf //利用する変数を定義

ALICLOUD_ACCESS_KEY=STEP2で作成したアクセスキーを設定
ALICLOUD_SECRET_KEY=STEP2で作成したシークレットキーを設定
ALICLOUD_REGION=リソースを構築したいリージョンのID

terraform {
  required_version = "= 0.14.5"

  backend "oss" {
  }

  required_providers {
    alicloud = {
      source  = "aliyun/alicloud"
      version = "1.114.1"
    }
  }
}

resource "alicloud_ram_user" "hoge" {
  name         = "hoge"
  display_name = "hoge"
}

# 実行内容を確認する
$ terraform plan -var-file='terraform/alibaba/staging/terraform.tfvars' terraform/alibaba

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # alicloud_ram_user.hoge will be created
  + resource "alicloud_ram_user" "hoge" {
      + display_name = "hoge"
      + force        = false
      + id           = (known after apply)
      + name         = "hoge"
    }

Plan: 1 to add, 0 to change, 0 to destroy.

------------------------------------------------------------------------

Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.

# applyする
$ terraform plan -var-file='terraform/alibaba/staging/terraform.tfvars' terraform/alibaba

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:

Terraform will perform the following actions:

  # alicloud_ram_user.hoge will be created
  + resource "alicloud_ram_user" "hoge" {
      + display_name = "hoge"
      + force        = false
      + id           = (known after apply)
      + name         = "hoge"
    }

Plan: 1 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

alicloud_ram_user.hoge: Modifying... [id=xxxxxxxx]
alicloud_ram_user.hoge: Modifications complete after 4s [id=xxxxxxxx]

terraform {
  required_version = "= 0.14.5"

  backend "oss" {
  }

  required_providers {
    alicloud = {
      source  = "aliyun/alicloud"
      version = "1.114.1"
    }
  }
}

resource "alicloud_oss_bucket" "infra" {
  bucket        = "infra"
  acl           = "private"
  storage_class = "Standard"
  versioning {
    status = "Enabled"
  }
}

bucket = "infra"
region = "利用したいリージョンのID"
prefix = "terraform/alibaba/" #tfstateファイルをアップロードしたOSSのパス
key    = "terraform.tfstate"  

$ terraform init -reconfigure -backend-config='terraform/alibaba/staging/backend.tf' terraform/alibaba

Initializing the backend...

Successfully configured the backend "oss"! Terraform will automatically
use this backend unless the backend configuration changes.

Initializing provider plugins...
- Reusing previous version of aliyun/alicloud from the dependency lock file
- Installing aliyun/alicloud v1.114.1...
- Installed aliyun/alicloud v1.114.1 (signed by a HashiCorp partner, key ID xxxxxxxxxxxxxxx)

Partner and community providers are signed by their developers.
If you'd like to know more about provider signing, you can read about it here:
https://www.terraform.io/docs/plugins/signing.html

Terraform has been successfully initialized!