After a while of running Openstack and performing a lot of testing (especially Tempest) you may find that your database seems to get pretty full … and this is partly down to expired keystone token’s that remain in the DB table.
To resolve this simply setup a periodic Cron job to execute
# /usr/bin/keystone-manage token_flush
This will remove all expired tokens to help clean-up the DB a bit
Of course, this action better to insert as cron task:
# cat keystone_token_flush
10 * * * * root /usr/bin/keystone-manage token_flush