feat: make postgresql on persistent storage

make data survice even terraform destroy (volume is detached from VM lifecycle)
data is not migrated, when volume already populated

infra-modules/postgres-vm/main.tf

@@ -29,3 +29,9 @@ resource "digitalocean_firewall" "db-fw" {
     source_addresses = [var.vpc.ip_range]
   }
 }
+
+resource "digitalocean_volume_attachment" "persistent-volume" {
+  count      = var.volume_id != null ? 1 : 0
+  droplet_id = digitalocean_droplet.psql-vm[local.instances[0]].id
+  volume_id  = var.volume_id
+}

infra-modules/postgres-vm/variables.tf

@@ -34,4 +34,10 @@ variable "vpc" {
     ip_range = string
   })
   description = "VPC network to where instance live"
-}
+}
+
+variable "volume_id" {
+  type        = string
+  default     = null
+  description = "Volume ID for attaching persistent storage to instance"
+}

infra-modules/volumes/main.tf

@@ -0,0 +1,36 @@
+variable "name" {
+  type        = string
+  description = "Name of network volume"
+}
+variable "region" {
+  type        = string
+  default     = "fra1"
+  description = "Region of network volume. Must match droplet"
+}
+variable "size" {
+  default     = 1
+  type        = number
+  description = "Volume size in GiB"
+}
+
+variable "fs_label" {
+  default     = "example"
+  type        = string
+  description = "Filesystem label for volume, useful for mounting"
+
+  validation {
+    condition = length(var.fs_label) <= 16
+    error_message = "Max 16 characters for FS label for ext4 filesystem"
+  }
+}
+resource "digitalocean_volume" "volume" {
+  name                     = var.name
+  region                   = var.region
+  size                     = var.size
+  initial_filesystem_type  = "ext4"
+  initial_filesystem_label = var.fs_label
+}
+
+output "volume_id" {
+  value = digitalocean_volume.volume.id
+}