RFE: tripleo-validation should warn when parameters in env files are overridden by other env files

[Dan Sneddon]

If I deploy tripleo with multiple environment files that include the same default parameters with different values, the last one included wins. This can cause a surprise for the deployer. We should create a tripleo-validation which tests the included environment files for duplicate parameters/parameter_defaults and warns when one value is overridden by another file.

For instance, if this is my deploy command-line:

openstack overcloud deploy --templates \
-e environments/network-isolation.yaml \
-e environments/neutron-ovs-dvr.yaml \
-e network-environment.yaml \
-r roles_data.yaml \
--control-scale 1 \
--compute-scale 2 \
--control-flavor control \
--compute-flavor compute \
--ntp-server 10.1.24.11

Assume that the parameter_default for OS::TripleO::Compute::Ports::ExternalPort is different in network-isolation.yaml than it is in neutron-ovs-dvr.yaml, then the value in neutron-ovs-dvr.yaml will override the value in network-isolation.yaml. This creates different outcomes depending on which file was included last.

It would be best if a warning were printed during deployment to assist with troubleshooting. The warning should happen whenever a parameter_default in one included environment file is overridden by another included environment file with a different value for the parameter.

[Cédric Jeanneret (cjeanner)]

Those scale/flavour options are deprecated already, and there's a warning about them anyway. They should be dropped sooner or later.