Comment 7 for bug 1717918

> We also need to modify heat to create trust. Add allow_redelegation=True parameter

You can set allow_redelegation=True in [trust] section of keystone.conf[1.]

However, redelegation does not seem to work atm (possibly keystone issue) as discussed in[2].

[1] https://github.com/openstack/keystone/blob/fab399e26cdbe7cffba895f99d7247896ec6cb82/keystone/conf/trust.py#L25

[2] https://bugs.launchpad.net/heat/+bug/1701498