Cause: When running the command `openstack overcloud deploy` to update a deployment from a directory that wasn't used when creating the deployment the password file wont be found. This results in a new password file being generated and new random passwords will be passed to Heat.
Consequence: Heat will attempt to reconfigure the passwords for all the overcloud services, but this isn't fully supported.
Workaround (if any): Make sure that all calls to update a deployment are done from the same directory. To check you are in the correct directory, look for a file called tripleo-overcloud-passwords.