This patch introduces an override for the number of Heat engine and Heat API workers: - heat_engine_workers - heat_api_workers The values may be set in /etc/openstack_deploy/user_variables.yml and if they are unset, half the number of available vCPU's will be used instead. Implements: blueprint gate-split Change-Id: I1ecb4951fe8336d9ef86ef9d5c8c21105a299096