PendingReleaseNotes: add note about upgrading MDS

Fixes: https://tracker.ceph.com/issues/23172
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit 9c809d3c58126694e577ade6d017e61a6c283411)

Conflicts:
	PendingReleaseNotes: added section 12.2.5 with cephfs release notes

diff --git a/PendingReleaseNotes b/PendingReleaseNotes
index ac6b2c0c67a2719ca8ef2c84836e4f5c0f67083a..6c70011721a2bca903dc6082d7fdad265663a4c0 100644 (file)
--- a/PendingReleaseNotes
+++ b/PendingReleaseNotes
@@ -54,3 +54,20 @@
     and refuses to start as consistency and untrimmable cache issues may
     develop. The new option client_die_on_failed_dentry_invalidate (default:
     true) may be turned off to allow the client to proceed (dangerous!).
+
+12.2.5
+------
+
+- *CephFS*:
+
+  * Upgrading an MDS cluster to 12.2.3+ will result in all active MDS
+    exiting due to feature incompatibilities once an upgraded MDS comes online
+    (even as standby). Operators may ignore the error messages and continue
+    upgrading/restarting or follow this upgrade sequence:
+
+    Reduce the number of ranks to 1 (`ceph fs set <fs_name> max_mds 1`),
+    deactivate all other ranks (`ceph mds deactivate <fs_name>:<n>`), shutdown
+    standbys leaving the one active MDS, upgrade the single active MDS, then
+    upgrade/start standbys. Finally, restore the previous max_mds.
+
+    See also: https://tracker.ceph.com/issues/23172