[lxc-devel] [lxd/stable-4.0] lxd/cluster/connect: Adds workaround for remote storage pool volumes using old schema in ConnectIfVolumeIsRemote

[tomponline on Github]

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From 92bee7be07b765539ef3db22ca9b870c405ec23f Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Fri, 30 Oct 2020 11:51:40 +0000
Subject: [PATCH] lxd/cluster/connect: Adds workaround for remote storage pool
 volumes using old schema in ConnectIfVolumeIsRemote

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 lxd/cluster/connect.go | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/lxd/cluster/connect.go b/lxd/cluster/connect.go
index 335341b022..8d81a11011 100644
--- a/lxd/cluster/connect.go
+++ b/lxd/cluster/connect.go
@@ -137,6 +137,23 @@ func ConnectIfVolumeIsRemote(s *state.State, poolName string, projectName string
 			return err
 		}
 
+		addressesCount := len(addresses)
+		if addressesCount > 1 {
+			clusterMemberCount, err := tx.GetNodesCount()
+			if err != nil {
+				return err
+			}
+
+			// Earlier schema versions created a volume DB record associated to each node in the
+			// cluster for remote storage pools, so if the address count equals the cluster member
+			// count then we take this to mean that the volume doesn't have an explicit cluster member
+			// and is therefore equivalent to db.ErrNoClusterMember that is used in newer schemas where
+			// a single remote volume DB record is created that is not associated to any single member.
+			if addressesCount == clusterMemberCount {
+				return db.ErrNoClusterMember
+			}
+		}
+
 		return nil
 	})
 	if err != nil && err != db.ErrNoClusterMember {