..
      Licensed under the Apache License, Version 2.0 (the "License"); you may
      not use this file except in compliance with the License. You may obtain
      a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
      License for the specific language governing permissions and limitations
      under the License.

============
Environments
============

The environment is used to affect the runtime behaviour of the
template. It provides a way to override the default resource
implementation and the parameters passed to Heat.

------
Format
------
It is a yaml text file with two main sections "resource_registry" and "parameters".

------------------
Command line usage
------------------
::

  heat stack-create -e my_env.yaml -P "some_parm=bla" -f my_tmpl.yaml

--------------
Usage examples
--------------

1) Pass parameters into Heat
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
::

  parameters:
    KeyName: heat_key
    InstanceType: m1.micro
    ImageId: F18-x86_64-cfntools


2) Deal with the renaming of Quantum to Neutron
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
::

  resource_registry:
    "OS::Quantum*": "OS::Neutron*"


3) Override a resource type with a custom TemplateResource
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
::

  resource_registry:
    "AWS::EC2::Instance": file:///home/mine/my_instance_with_better_defaults.yaml


4) Always map resource type X to Y
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
::

  resource_registry:
    "OS::Networking::FloatingIP": "OS::Nova::FloatingIP"


5) Use default resources except one for a particular resource in the template
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
::

  resource_registry:
    resources:
      my_db_server:
        "OS::DBInstance": file:///home/mine/all_my_cool_templates/db.yaml
