From 31df8c6bf2711fd0d82ad4d9c866ab6e0845de14 Mon Sep 17 00:00:00 2001
From: Nikolay Vinogradov <nikolay.vinogradov@canonical.com>
Date: Wed, 12 Oct 2022 07:22:51 +0300
Subject: [PATCH] Add storage-backend subordinate relation

Implement initial support for container-scoped storage-backend
relation to integrate nova-compute with storage providers.

Transition to blocked state if multiple storage backend
relations are connected

Change-Id: I03e67731df0263887d2d0f671750f420d6e62c1c
---
 hooks/nova_compute_utils.py | 3 +++
 metadata.yaml               | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/hooks/nova_compute_utils.py b/hooks/nova_compute_utils.py
index 6dcd548f..8fd56917 100644
--- a/hooks/nova_compute_utils.py
+++ b/hooks/nova_compute_utils.py
@@ -1000,6 +1000,9 @@ def check_optional_config_and_relations(configs):
         except ValueError as e:
             return ('blocked', 'Invalid configuration: {}'.format(str(e)))
 
+    if len(relation_ids('storage-backend')) > 1:
+        return 'blocked', "Multiple storage backends are not supported"
+
     # return 'unknown' as the lowest priority to not clobber an existing
     # status.
     return "unknown", ""
diff --git a/metadata.yaml b/metadata.yaml
index ca1571c3..afbd5ecf 100644
--- a/metadata.yaml
+++ b/metadata.yaml
@@ -54,6 +54,9 @@ requires:
     interface: vault-kv
   ironic-api:
     interface: baremetal
+  storage-backend:
+    interface: storage-backend
+    scope: container
 peers:
   compute-peer:
     interface: nova