Description of problem:
If there is a typo in one of the templates describing the overcloud, the error message isn't overly helpful:

$ 
openstack overcloud deploy --templates ~/my_templates/ \
>    --ntp-server 10.5.26.10 \
>     --control-flavor control --compute-flavor compute --ceph-storage-flavor ceph \
>     --control-scale 3 --compute-scale 1 --ceph-storage-scale 3 \
>     --neutron-tunnel-types vxlan --neutron-network-type vxlan \
>     -e ~/my_templates/environments/storage-environment.yaml \
>     -e ~/my_templates/advanced-networking.yaml \
>     -e ~/my_templates/firstboot-environment.yaml
Deploying templates in the directory /home/stack/my_templates
ERROR: openstack ERROR: Failed to validate: Failed to validate: Error parsing template: while scanning a simple key
  in "<unicode string>", line 21, column 1
could not find expected ':'
  in "<unicode string>", line 22, column 1

At least the file where the error occurred would be nice.

Version-Release number of selected component (if applicable):
python-rdomanager-oscplugin-0.0.8-44.el7ost