For blog post "Highly available, read-replicated PostgreSQL with Google CloudSQL and Terraform"

replica.tf

resource "google_sql_database_instance" "read_replica" {
  name                 = "replica-${random_id.db_name_suffix.hex}"
  master_instance_name = "${var.project_id}:${google_sql_database_instance.master.name}"
  region               = "europe-west4"
  database_version     = "POSTGRES_11"

  replica_configuration {
    failover_target = false
  }

  settings {
    tier              = "db-f1-micro"
    availability_type = "ZONAL"
    disk_size         = "100"
    backup_configuration {
      enabled = false
    }
    ip_configuration {
      ipv4_enabled    = true
      private_network = "projects/${var.project_id}/global/networks/default"
    }
    location_preference {
      zone = "europe-west4-a"
    }
  }
}