Description of problem: Duplicate BlockDeviceMapping if attaching volumes too fast https://launchpad.net/bugs/1937375 When attaching a volume to a running instance the nova-api validates that the volume is not already attached to the instance. However nova-compute is responsible for actually creating the BDM entry in the database. If sending attach requests fast enough it can be possible that the same "attach_volume" request can be sent to nova-compute for the same volume/instance combination.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Release of components for Red Hat OpenStack Platform 17.0 (Wallaby)), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2022:6543