doc/rgw: document UserName requirements for account migration

clarify the following error when migrating a user into an account:

> could not modify user: unable to modify user, UserName contains invalid characters

Fixes: https://tracker.ceph.com/issues/69470
Signed-off-by: Casey Bodley <cbodley@redhat.com>

diff --git a/doc/radosgw/account.rst b/doc/radosgw/account.rst
index 6dab997d93e67a0edc0bc386e14aa9ca2c8ca557..0e4ede5a50a793ba227d8cdc751aa2564d142514 100644 (file)
--- a/doc/radosgw/account.rst
+++ b/doc/radosgw/account.rst
@@ -174,6 +174,11 @@ An existing user can be adopted into an account with ``user modify``::
 .. note:: Account membership is permanent. Once added, users cannot be
    removed from their account.
 
+.. note:: The IAM User API imposes additional requirements on the format
+   of ``UserName``, which is enforced when migrating users into an account.
+   If migration fails with "UserName contains invalid characters", the
+   ``--display-name`` should be modified to match ``[\w+=,.@-]+``.
+
 .. warning:: Ownership of the user's notification topics will not be
    transferred to the account. Notifications will continue to work, but
    the topics will no longer be visible to SNS Topic APIs. Topics and