Cloned from launchpad blueprint https://blueprints.launchpad.net/sahara/+spec/cluster-creation-with-trust.
Creation of cluster could be a pretty long operation. Now we use session that usually expire in less than hour. So, currently it is impossible to create cluster that require more than 1 hour for spawn.
Sahara could get trust from user and use it whatever it is needed for cluster creation.
Specification URL (additional information):