Terraform部署GCP托管实例组遇属性不存在报错求助

问题场景 #

我用以下Terraform代码在GCP部署托管实例组，通过data.terraform_remote_state引用现有基础架构资源的数据时，出现了属性不存在的错误：

resource "google_compute_instance_template" "this" {
  name_prefix  = var.mig.instance_template_name_prefix
  region       = var.region
  machine_type = var.mig.machine_type
  disk {
    source_image = var.mig.source_image
  }
  network_interface {
    subnetwork = data.terraform_remote_state.foundation.outputs.subnetwork_self_links["iowa"]
    access_config {
      // Ephemeral public IP
    }
  }
  metadata_startup_script = file("startup.sh")
  tags = [
    "allow-iap",
    "allow-health-check"
  ]
  service_account {
    email  = data.terraform_remote_state.foundation.outputs.service_account_email
    scopes = ["cloud-platform"]
  }
  lifecycle {
    create_before_destroy = true
  }
}
resource "google_compute_region_instance_group_manager" "this" {
  name               = var.mig.mig_name
  region             = var.region
  base_instance_name = var.mig.mig_base_instance_name
  target_size        = var.mig.target_size
  version {
    instance_template = google_compute_instance_template.this.id
  }
  named_port {
    name = "http"
    port = 80
  }
  update_policy {
    type            = "PROACTIVE"
    minimal_action  = "REPLACE"
    max_surge_fixed = 3
  }
}

错误信息 #

Plan: 1 to add, 0 to change, 0 to destroy.
╷
│ Error: Unsupported attribute
│ 
│   on mig.tf line 12, in resource "google_compute_instance_template" "this":
│   12:     subnetwork = data.terraform_remote_state.foundation.outputs.subnetwork_self_links["iowa"]
│     ├────────────────
│     │ data.terraform_remote_state.foundation.outputs is object with no attributes
│ 
│ This object does not have an attribute named "subnetwork_self_links".
╵
╷
│ Error: Unsupported attribute
│ 
│   on mig.tf line 25, in resource "google_compute_instance_template" "this":
│   25:     email  = data.terraform_remote_state.foundation.outputs.service_account_email
│     ├────────────────
│     │ data.terraform_remote_state.foundation.outputs is object with no attributes
│ 
│ This object does not have an attribute named "service_account_email".

解决建议 #

• 核对remote_state数据源配置
  确认data "terraform_remote_state" "foundation"的配置是否正确指向了存储基础架构状态的后端（比如GCS桶、S3等）。若后端路径、桶名或工作区有误，会导致读取不到正确的输出值。

• 确认基础架构模块的输出定义
  生成foundation状态的Terraform代码必须明确定义对应输出，否则remote_state无法读取。在基础架构模块的outputs.tf中添加以下内容（根据实际资源调整value）：

  output "subnetwork_self_links" {
    type        = map(string)
    description = "子网的自链接"
    value       = google_compute_subnetwork.your_subnet_resource.*.self_link
  }
  
  output "service_account_email" {
    type        = string
    description = "服务账号邮箱"
    value       = google_service_account.your_sa_resource.email
  }
  

• 刷新状态数据
  执行terraform refresh或重新应用基础架构模块，确保状态文件已更新并包含最新的输出值。

• 检查输出名称拼写
  确保代码中引用的subnetwork_self_links和service_account_email与基础架构模块输出的名称完全一致，大小写、下划线都不能出错。

内容的提问来源于stack exchange，提问作者Nani