使用Backstage和Terraform创建Postgres实例时遇Cloud SQL实例不存在404错误求助

计划通过Backstage结合Terraform预定义模板创建Postgres实例，执行terraform plan时返回以下错误：

Error: googleapi: Error 404: The Cloud SQL instance does not exist., instanceDoesNotExist
with module.postgres_instance.google_sql_database.databases["default_db"]
on .terraform/modules/postgres_instance/main.tf line 1, in resource "google_sql_database" "databases":
resource "google_sql_database" "databases" {

Error: googleapi: Error 404: The Cloud SQL instance does not exist., instanceDoesNotExist
with module.postgres_instance.google_sql_user.iam_service_account[0]
on .terraform/modules/postgres_instance/iam.tf line 10, in resource "google_sql_user" "iam_service_account":
resource "google_sql_user" "iam_service_account" {

已尝试以下两种方案，但问题未解决，请求协助排查：

• 通过gcloud命令验证当前项目下无对应Cloud SQL实例：

  C:\Windows\system32> gcloud sql instances list
  

  执行后确认控制台及命令行均未找到目标实例。
• 在Terraform配置中手动添加了以下资源定义：

  resource "google_sql_user" "iam_service_account" {
    instance = "ew2-wrk-dev-wrk01-svp-sqp-db1sq"
    name     = "dv-gsa-res-sqm-1@wrk-dev-wrk01-svp-021463.iam"
    project  = "XXXXXXX"
    type     = "CLOUD_IAM_SERVICE_ACCOUNT"
  }
  
  resource "google_sql_database" "databases" {
    name     = "default_db"
    instance = "ew2-wrk-dev-wrk01-svp-sqp-db1sq"
    project  = "XXXXXX"
  }
  

内容的提问来源于stack exchange，提问作者Hareesh Kumar Sure