Keystone SPASSWORD is an OpenStack Keystone extension that enables some extra security checks over user passwords, as force the usage of strong passwords, expiration time for a password, number of bad login attempts before user account became temporarily blocked, a recover procedure password, second factor authentication (2FA), etc.
It seems fernet keys are fixed at image creation.
Once a day docker container is rotating fernet keys.
Some problems in HA balanced scenarios could happend if nodes does not share fernet keys or uses sticky sessions.
https://docs.openstack.org/keystone/pike/admin/identity-fernet-token-faq.html
How enable sticky sessions: https://thisinterestsme.com/haproxy-sticky-sessions/ A workaround could be not rotate fernet keys by default.