a9d9dbec1c
Commit bc93bb5f fixed a typo in the autogenerated output of the HOT
guide. This patch imports the fix in the source file.
Change-Id: I66801444324d82fb4b5a1ab7775d29f9d606af85
128 lines
3.9 KiB
ReStructuredText
128 lines
3.9 KiB
ReStructuredText
.. _environments:
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============
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Environments
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============
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The environment affects the runtime behaviour of a template. It provides a way
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to override the resource implementations and a mechanism to place parameters
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that the service needs.
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To fully understand the runtime behavior you have to consider what plug-ins are
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installed on the cloud you're using.
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Environment file format
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-----------------------
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The environment is a yaml text file that contains two main sections:
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``parameters``
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A map of key/pair values.
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``resource_registry``
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Definition of custom resources.
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Use the :option:`-e` option of the :command:`heat stack-create` command to
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create a stack using with the environment defined in such a file.
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You can also provide environment parameters as a list of key/value pairs using
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the :option:`-P` option of the :command:`heat stack-create` command.
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In the following example the environment is read from the :file:`my_env.yaml`
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file and an extra parameter is provided using the :option:`-P` option:
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.. code-block:: console
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$ heat stack-create my_stack -e my_env.yaml -P "param1=val1;param2=val2" -f my_tmpl.yaml
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Global and effective environments
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---------------------------------
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The environment used for a stack is the combination of the environment you
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use with the template for the stack, and a global environment that is
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determined by your cloud operator. An entry in the user environment takes
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precedence over the global environment. OpenStack includes a default global
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environment, but you cloud operator can add additional environment entries.
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.. TODO:
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move this to a heat section in the admin-guide-cloud
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The cloud operator can add to the global environment
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by putting environment files in a configurable directory wherever
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the Orchestration engine runs. The configuration variable is named
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"environment_dir" is found in the "[DEFAULT]" section
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of "/etc/heat/heat.conf". The default for that directory is
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"/etc/heat/environment.d". Its contents are combined in whatever
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order the shell delivers them when the service starts up,
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which is the time when these files are read.
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If the "my_env.yaml" file from the example above had been put in the
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"environment_dir" then the user's command line could be this:
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::
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heat stack-create my_stack -P "some_parm=bla" -f my_tmpl.yaml
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Define values for a template arguments
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--------------------------------------
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You can define values for the template arguments in the ``parameters`` section
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of an environment file:
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.. code-block:: yaml
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parameters:
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KeyName: my_keypair
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InstanceType: m1.tiny
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ImageId: F18-x86_64-cfntools
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Create and override resources
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-----------------------------
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You can create or override resources in the ``resource_registry`` section of an
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environment file. The resource you provide in this manner must have an
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identifier, and references either other resources IDs or the URL of an existing
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template file.
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The following example maps the new ``OS::Networking::FloatingIP``
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resource to the existing :hotref:`OS::Nova::FloatingIP` resource:
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.. code-block:: yaml
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resource_registry:
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"OS::Networking::FloatingIP": "OS::Nova::FloatingIP"
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You can use wildcards to map multiple resources:
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.. code-block:: yaml
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resource_registry:
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"OS::Network*": "OS::Neutron*"
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To create or override a resource with a custom resource, create a template file
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to define this resource, and provide the URL to the template file in the
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environment file:
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.. code-block:: yaml
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resource_registry:
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"AWS::EC2::Instance": file:///path/to/my_instance.yaml
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The supported URL scheme are ``file``, ``http`` and ``https``.
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.. note::
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The template file extension must be ``.yaml`` or ``.template``, or it will
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not be treated as a custom template resource.
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You can limit the usage of a custom resource to a specific resource of the
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template:
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.. code-block:: yaml
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resource_registry:
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resources:
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my_db_server:
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"OS::DBInstance": file:///home/mine/all_my_cool_templates/db.yaml
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