feat(corp/ops): configure state bucket for terraform

This was a bit trickier than I anticipated, because there's no good
ways to avoid passing the credentials around manually.

What's basically happening now is that the credentials for the state
bucket are checked in (encrypted), and sourcing `creds.fish` uses the
cloud HSM to decrypt and load them into the environment.

Change-Id: I3f5ce1c9bd9d5efbf1013414f94771a09ea3a488
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8494
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

corp/ops/creds.fish

@@ -0,0 +1,5 @@
+export YC_TOKEN=(yc iam create-token)
+export YC_CLOUD_ID=(yc config get cloud-id)
+export YC_FOLDER_ID=(yc config get folder-id)
+export AWS_ACCESS_KEY_ID="YCAJE6eRLY8Az-9kveNRtz4sh"
+export AWS_SECRET_ACCESS_KEY=(yc kms symmetric-crypto decrypt --name tvl-credentials --cloud-id b1ggu5m1btue982app12 --folder-name default --ciphertext-file encrypted-state-secret.key --plaintext-file /dev/stdout | head -n1)

corp/ops/main.tf

@@ -7,4 +7,71 @@ terraform {
       source = "yandex-cloud/yandex"
     }
   }
+
+  # Credentials need to be sourced from creds.fish
+  backend "s3" {
+    endpoint = "storage.yandexcloud.net"
+    bucket   = "su-tvl-terraform-state"
+    region   = "ru-central1"
+    key      = "corp/ops/terraform.tfstate"
+
+    skip_region_validation      = true
+    skip_credentials_validation = true
+  }
+}
+
+provider "yandex" {
+  zone = "ru-central1-b"
+}
+
+locals {
+  tvl_cloud_id  = "b1ggu5m1btue982app12"
+  tvl_folder_id = "b1gmbeqt9o5kbl7rclln"
+  rih_cloud_id  = "b1glccvcqggi2ruibgvt"
+  rih_folder_id = "b1gsavcrsjn059d1sbh9"
+}
+
+# Storage state bucket configuration
+
+resource "yandex_iam_service_account" "tf_state_sa" {
+  folder_id = local.tvl_folder_id
+  name      = "terraform-state"
+}
+
+resource "yandex_resourcemanager_folder_iam_member" "tf_state_sa_storage" {
+  folder_id = local.tvl_folder_id
+  role      = "storage.editor"
+  member    = "serviceAccount:${yandex_iam_service_account.tf_state_sa.id}"
+}
+
+resource "yandex_iam_service_account_static_access_key" "tf_state_sa_key" {
+  service_account_id = yandex_iam_service_account.tf_state_sa.id
+  description        = "Static access key for Terraform state"
+}
+
+resource "yandex_storage_bucket" "tf_state" {
+  access_key = yandex_iam_service_account_static_access_key.tf_state_sa_key.access_key
+  secret_key = yandex_iam_service_account_static_access_key.tf_state_sa_key.secret_key
+  bucket     = "su-tvl-terraform-state"
+}
+
+resource "yandex_dns_zone" "russiaishiring_com" {
+  name      = "russiaishiring-com"
+  zone      = "russiaishiring.com."
+  public    = true
+  folder_id = local.rih_folder_id
+}
+
+# Secret management configuration
+
+resource "yandex_kms_symmetric_key" "tvl_credentials_key" {
+  name              = "tvl-credentials"
+  folder_id         = local.tvl_folder_id
+  default_algorithm = "AES_256"
+  rotation_period   = "2160h" # 90 days
+}
+
+resource "yandex_kms_secret_ciphertext" "tf_state_key" {
+  key_id    = yandex_kms_symmetric_key.tvl_credentials_key.id
+  plaintext = yandex_iam_service_account_static_access_key.tf_state_sa_key.secret_key
 }