How to Import an Google VPC Subnetwork into Terraform

Import Google VPC Subnetwork with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Google Compute Engine resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live Google VPC Subnetwork to managed Terraform.

terraback scan all gcp --project my-gcp-project

terraback gcp import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = google_compute_subnetwork.app
  id = "projects/my-project/regions/us-central1/subnetworks/app"
}

Example google_compute_subnetwork configuration

Here is a realistic Google VPC Subnetwork block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "google_compute_subnetwork" "app" {
  name          = "app"
  ip_cidr_range = "10.0.1.0/24"
  region        = "us-central1"
  network       = google_compute_network.vpc.id
}

Gotchas when importing a Google VPC Subnetwork

• Subnetworks are regional; the import ID must include the region segment.
• Secondary IP ranges (for GKE pods and services) import inline as secondary_ip_range blocks; copy them exactly.
• The parent network must use auto_create_subnetworks = false for a custom subnetwork to coexist cleanly.

Doing it manually with terraform import

The native approach is to write the google_compute_subnetwork block by hand, then run terraform import google_compute_subnetwork.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other Google Cloud resources