heat/doc/source/glossary.rst

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==========
 Glossary
==========

.. glossary::
   :sorted:

   API server
     HTTP REST API service for heat.

   CFN
     An abbreviated form of "AWS CloudFormation".

   constraint
     Defines valid input :term:`parameters` for a :term:`template`.

   dependency
     When a :term:`resource` must wait for another resource to finish
     creation before being created itself. Heat adds an implicit
     dependency when a resource references another resource or one of
     its :term:`attributes <resource attribute>`. An explicit
     dependency can also be created by the user in the template
     definition.

   environment
     Used to affect the run-time behavior of the template. Provides a
     way to override the default resource implementation and
     parameters passed to Heat. See :ref:`Environments`.

   Heat Orchestration Template
     A particular :term:`template` format that is native to Heat.
     Heat Orchestration Templates are expressed in YAML and are not
     backwards-compatible with CloudFormation templates.

   HOT
     An acronym for ":term:`Heat Orchestration Template`".

   input parameters
     See :term:`parameters`.

   Metadata
     May refer to :term:`Resource Metadata`, :term:`Nova Instance
     metadata`, or the :term:`Metadata service`.

   Metadata service
     A Compute service that enables virtual machine instances to
     retrieve instance-specific data. See :nova-doc:`Nova Metadata
     service documentation <user/metadata.html#metadata-service>`.

   multi-region
     A feature of Heat that supports deployment to multiple regions.

   nested resource
     A :term:`resource` instantiated as part of a :term:`nested
     stack`.

   nested stack
     A :term:`template` referenced by URL inside of another template.
     Used to reduce redundant resource definitions and group complex
     architectures into logical groups.

   Nova Instance metadata
     User-provided *key:value* pairs associated with a Compute
     Instance. See `Instance-specific data (OpenStack Operations Guide)`_.

     .. _Instance-specific data (OpenStack Operations Guide): https://wiki.openstack.org/wiki/OpsGuide/User-Facing_Operations#using-instance-specific-data

   OpenStack
     Open source software for building private and public clouds.

   orchestrate
     Arrange or direct the elements of a situation to produce a
     desired effect.

   outputs
     A top-level block in a :term:`template` that defines what data
     will be returned by a stack after instantiation.

   parameters
     A top-level block in a :term:`template` that defines what data
     can be passed to customise a template when it is used to create
     or update a :term:`stack`.

   provider resource
     A :term:`resource` implemented by a :term:`provider
     template`. The parent resource's properties become the
     :term:`nested stack's <nested stack>` parameters.

   provider template
     Allows user-definable :term:`resource providers <resource
     provider>` to be specified via :term:`nested stacks <nested
     stack>`. The nested stack's :term:`outputs` become the parent
     stack's :term:`attributes <resource attribute>`.

   resource
     An element of OpenStack infrastructure instantiated from a
     particular :term:`resource provider`. See also :term:`nested
     resource`.

   resource attribute
     Data that can be obtained from a :term:`resource`, e.g. a
     server's public IP or name. Usually passed to another resource's
     :term:`properties <resource property>` or added to the stack's
     :term:`outputs`.

   resource group
     A :term:`resource provider` that creates one or more identically
     configured :term:`resources <resource>` or :term:`nested
     resources <nested resource>`.

   Resource Metadata
     A :term:`resource property` that contains CFN-style template
     metadata. See `AWS::CloudFormation::Init (AWS CloudFormation User Guide)`_

     .. _AWS::CloudFormation::Init (AWS CloudFormation User Guide): https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-init.html

   resource plugin
     Python code that understands how to instantiate and manage a
     :term:`resource`. See `Heat Resource Plugins (OpenStack wiki)`_.

     .. _Heat Resource Plugins (OpenStack wiki): https://wiki.openstack.org/wiki/Heat/Plugins#Heat_Resource_Plugins

   resource property
     Data utilized for the instantiation of a :term:`resource`. Can be
     defined statically in a :term:`template` or passed in as
     :term:`input parameters <parameters>`.

   resource provider
     The implementation of a particular resource type. May be a
     :term:`resource plugin` or a :term:`provider template`.

   stack
     A collection of instantiated :term:`resources <resource>` that
     are defined in a single :term:`template`.

   stack resource
     A :term:`resource provider` that allows the management of a
     :term:`nested stack` as a :term:`resource` in a parent stack.

   template
     An orchestration document that details everything needed to carry
     out an :term:`orchestration <orchestrate>`.

   template resource
     See :term:`provider resource`.

   user data
     A :term:`resource property` that contains a user-provided data
     blob. User data gets passed to `cloud-init`_ to automatically
     configure instances at boot time. See also :nova-doc:`Nova User data
     documentation <user/metadata.html#user-provided-data>`.

     .. _cloud-init: https://cloudinit.readthedocs.io/

   wait condition
     A :term:`resource provider` that provides a way to communicate
     data or events from servers back to the orchestration
     engine. Most commonly used to pause the creation of the
     :term:`stack` while the server is being configured.