How to fix Error: Error creating VPC Network: ResourceAlreadyExists in Terraform

Verify the network exists by listing all networks in your GCP project:

gcloud compute networks list

Look for a network with the name matching your Terraform configuration. This confirms the resource exists in GCP.

If the network exists in GCP but not in your Terraform state, import it using the terraform import command:

terraform import google_compute_network.network_name projects/PROJECT_ID/global/networks/network-name

Replace PROJECT_ID with your GCP project ID and network-name with the actual VPC network name. After importing, Terraform will track this existing resource.

Ensure your Terraform code matches the actual network configuration in GCP. Check resource properties like:

resource "google_compute_network" "vpc_network" {
  name                    = "existing-network-name"
  auto_create_subnetworks = false  # Adjust to match actual config
}

Run terraform plan to verify there are no changes needed.

If the network is no longer needed and no other resources depend on it, delete it manually and then run Terraform again:

gcloud compute networks delete network-name --quiet
terraform apply

Be careful—this will remove the network and all dependent resources. Only do this in development environments.

For Terraform 1.5 and later, use the import block in your configuration for cleaner management:

import {
  id = "projects/PROJECT_ID/global/networks/network-name"
  to = google_compute_network.vpc_network
}

Run terraform plan to validate the import, then commit the changes.

Prevent state loss by configuring a remote backend like Google Cloud Storage:

terraform {
  backend "gcs" {
    bucket = "my-tfstate-bucket"
    prefix = "env/prod"
  }
}

This ensures your state persists across environments and team members have consistent state.