Service Chain Driver refactoring
Co-Authored-By: Hemanth Ravi <hemanth.ravi@oneconvergence.com> Co-Authored-By: Ivar Lazzaro <ivarlazzaro@gmail.com> Co-Authored-By: Igor Duarte Cardoso <igordcard@gmail.com> Co-Authored-By: Ranga Rajagopalan <rangar@avinetworks.com> Co-Authored-By: Isaku Yamahata <isaku.yamahata@intel.com> Defines: blueprint node-centric-chain-plugin Change-Id: I9b5f3870dcbaf9e9bc49d47f7f8147fc970b95cd
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Sumit Naiksatam
Ivar Lazzaro
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specs/kilo/gbp-service-chain-driver-refactor.rst
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specs/kilo/gbp-service-chain-driver-refactor.rst
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..
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This work is licensed under a Creative Commons Attribution 3.0 Unported
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License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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==========================================
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Service Chain Driver Refactor
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==========================================
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Problem description
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===================
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Current service chain driver is a monolithic entity that couples the service
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chaining logic along with the service configuration logic. Decoupling of these
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entities will allow development of a service configuration driver independent
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of the chaining mechanism.
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Proposed change
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===============
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At a high level the following changes are proposed:
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1. Refactor current Service Chain Service structure in order to
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easily accommodate new plugins;
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2. Create a new API object called "Service Profile". This object
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contains a set of attributes that can describe the service
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(eg. service_type, vendor, insertion_mode and so forth).
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Service Profile will be extensible from day one;
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3. Replace the "service_type" attribute on the Service Chain Node
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with the "service_profile" attribute. The latter is an UUID
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pointing to an existing Service Profile object;
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4. Create a new "Node Composition Plugin". The Plugin can load one or
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multiple "Node Driver(s)". A Node Driver is capable of deploying,
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destroying and updating Service Chain Node instances depending
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on their profile;
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4.1. The plumbing info of all the scheduled nodes will be used by the
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NCP for traffic stitching/steering. This will be a pluggable module.
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5. Define Service Configuration and Management driver interface;
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6. Implement 2 reference implementations of Node Drivers.
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They will use Nova (for NFV) and Neutron in the backend.
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The relationship between the Services Plugin and Node Drivers is as shown below:
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The Node Composition Plugin implementation is designed as the following class
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hierarchy:
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asciiflow::
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+--------------------------------------+ +---------------------------+
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|NodeComposPlugin(ServiceChainDbPlugin)| | NodeDriverBase |
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| |1 N| |
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| +--------------+ |
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+--------------------------------------+ +---------------------------+
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| *create *update *delete | | *get_plumbing_info() |
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| *SCI *SCI *SCI | | *validate(NodeContext) |
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| *SCS *SCS *SCS | | *create(NodeContext) |
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| *SCN *SCN *SCN | | *delete(NodeContext) |
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+--------------------------------------+ | *update(NodeContext) |
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+----^--------^--------^----+
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+--------------------------------------+ | | |
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| NodeContext | | | |
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| | +--------+----+ | +----+--------+
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| *core plugin | | | | | |
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| *sc plugin | | Nova | | | Neutron |
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| *provider ptg | | Node | | | Node |
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| *consumer ptg | | Driver | | | Driver |
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| *policy target(s) | | | | | |
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| *management ptg | | | | | |
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| *ser^ice chain instance | +-----^-------+ | +------^------+
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| *service chain node | | | |
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| *service chain spec | | | |
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+--------------------------------------+ | | |
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| | +-----+----+ +----+---+ +----+-----+
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| *get/update/delete service targets | | SC Node | | SC Node| | SC Node |
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| | | Driver | | Driver | | Driver |
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+--------------------------------------+ +----------+ +--------+ +----------+
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Node Driver Base
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This supports operations for CRUD of a service, and to query the number of
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data-path and management interfaces required for this service.
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Node Context
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Provides useful attributes and methods for the Node Driver to use.
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CRUD on "service targets" are useful to create service specific
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Policy Targets in defined PTGs (provider/consumer/management)
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The Node Driver operations are called as pre-/post-commit hooks.
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Service Targets
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This is an *internal only* construct. It's basically a normal Policy Target
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but with some metadata which makes easy to understand which service it
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belongs to, in which order, on which side of the relationship, for which
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Node, deployed by which driver. Will require a new table to store all
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these info.
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Nova Node Driver
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This provides a reusable implementation for managing the lifecycle of a
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service VM.
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Neutron Node Driver
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This provides a reusable implementation for managing existing Neutron
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services.
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Node Driver
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This configures the service based on the “config” provided in the Service
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Node definition.
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Data model impact
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-----------------
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Service Target
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* policy_target_id - PT UUID
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* service_chain_instance_id - SCI UUID
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* service_chain_node_id - SCN UUID, the one of the specific node this ST belongs to
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* relationship - Enum, PROVIDER|CONSUMER|MANAGEMENT
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* order - Int, order of the node within the chain
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Service Profile
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* id - standard object uuid
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* name - optional name
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* description - optional annotation
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* shared - whether the object is shared or not
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* vendor - optional string indicating the vendor
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* insertion_mode - string L2|L3|BITW|TAP
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* service_type - generic string (eg. LOADBALANCER|FIREWALL|...)
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* service_flavor - generic string (eg. m1.tiny)
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Service Chain Node
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* REMOVE service_type
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* service_profile_id - SP UUID
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REST API impact
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---------------
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The REST API changes look like follows::
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SERVICE_PROFILES: {
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'id': {'allow_post': False, 'allow_put': False,
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'validate': {'type:uuid': None}, 'is_visible': True,
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'primary_key': True},
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'name': {'allow_post': True, 'allow_put': True,
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'validate': {'type:string': None},
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'default': '', 'is_visible': True},
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'description': {'allow_post': True, 'allow_put': True,
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'validate': {'type:string': None},
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'is_visible': True, 'default': ''},
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'tenant_id': {'allow_post': True, 'allow_put': False,
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'validate': {'type:string': None},
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'required_by_policy': True, 'is_visible': True},
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attr.SHARED: {'allow_post': True, 'allow_put': True,
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'default': False, 'convert_to': attr.convert_to_boolean,
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'is_visible': True, 'required_by_policy': True,
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'enforce_policy': True},
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'vendor': {'allow_post': True, 'allow_put': True,
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'validate': {'type:string': None},
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'is_visible': True, 'default': ''},
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'insertion_mode': {'allow_post': True, 'allow_put': True,
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'validate': {'type:values':
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scc.VALID_INSERTION_MODES},
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'is_visible': True, 'default': None},
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'service_type': {'allow_post': True, 'allow_put': True,
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'validate': {'type:string': None},
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'is_visible': True, 'required': True},
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'service_flavor': {'allow_post': True, 'allow_put': True,
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'validate': {'type:string': None},
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'is_visible': True, 'required': True},
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}
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The following is added to servicechain node::
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SERVICECHAIN_NODES: {
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'service_profile_id': {'allow_post': True, 'allow_put': True,
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'validate': {'type:uuid': None},
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'required': True, 'is_visible': True},
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}
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Security impact
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---------------
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Notifications impact
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--------------------
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Other end user impact
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---------------------
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Performance impact
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------------------
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Other deployer impact
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---------------------
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TBD
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Developer impact
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----------------
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TBD
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Community impact
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----------------
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Alternatives
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------------
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Implementation
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==============
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Assignee(s)
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-----------
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* Ivar Lazzaro (mmaleckk)
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Work items
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----------
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Dependencies
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============
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Testing
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=======
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Tempest tests
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-------------
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Functional tests
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----------------
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API tests
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---------
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Documentation impact
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====================
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User documentation
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------------------
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Developer documentation
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-----------------------
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References
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==========
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