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diff --git a/docs/clamp/controlloop/controlloop-architecture.rst b/docs/clamp/controlloop/controlloop-architecture.rst deleted file mode 100644 index c5977ee4..00000000 --- a/docs/clamp/controlloop/controlloop-architecture.rst +++ /dev/null @@ -1,468 +0,0 @@ -.. This work is licensed under a Creative Commons Attribution 4.0 International License. - -.. _clamp-controlloop_architecture-label: - -TOSCA Defined Control Loops: Architecture and Design -#################################################### - - -.. contents:: - :depth: 4 - -The idea of using control loops to automatically (or autonomously) perform network management -has been the subject of much research in the Network Management research community, see -:download:`this paper <files/ControlLoops.pdf>` for some background. However, it is only with -the advent of ONAP that we have a platform that supports control loops for network management. -Before ONAP, Control Loops have been implemented by hard-coding components together and hard -coding logic into components. ONAP has taken a step forward towards automatic implementation -of Control Loops by allowing parameterization of Control Loops that work on the premise that -the Control Loops use a set of analytic, policy, and control components connected together in -set ways. - -The goal of the work is to extend and enhance the current ONAP Control Loop support to provide -a complete open-source framework for Control Loops. This will enhance the current support to -provide TOSCA based Control Loop definition and development, commissioning and run-time management. -The participants that comprise a Control Loop and the metadata needed to link the participants -together to create a Control Loop are specified in a standardized way using the `OASIS TOSCA -modelling language <http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/>`_. The TOSCA -description is then used to commission, instantiate, and manage the Control Loops in the run -time system. - -.. image:: images/01-controlloop-overview.png - -1 Terminology -============= - -This section describes the terminology used in the system. - -1.1 Control Loop Terminology ----------------------------- - -**Control Loop Type:** A definition of a Control Loop in the TOSCA language. This definition describes -a certain type of a control loop. The life cycle of instances of a Control Loop Type are managed -by CLAMP. - -**Control Loop Instance:** An instance of a Control Loop Type. The life cycle of a Control Loop -Instance is managed by CLAMP. A Control Loop Instance is a set of executing elements on which -Life Cycle Management (LCM) is executed collectively. For example, a set of microservices may be -spawned and executed together to deliver a service. This collection of services is a control loop. - -**Control Loop Element Type:** A definition of a Control Loop Element in the TOSCA language. This -definition describes a certain type of Control Loop Element for a control loop in a Control -Loop Type. - -**Control Loop Element Instance:** A single entity executing on a participant, with its Life Cycle -being managed as part of the overall control loop. For example, a single microservice that is -executing as one microservice in a service. - -**CLAMP Control Loop Runtime:** The CLAMP server that holds Control Loop Type definitions and manages -the life cycle of Control Loop Instances and their Control Loop Elements in cooperation with -participants. - - -1.2 Participant Terminology ---------------------------- - -**Participant Type:** Definition of a type of system or framework that can take part in control -loops and a definition of the capabilities of that participant type. A participant advertises -its type to the CLAMP Control Loop Runtime. - -**Participant:** A system or framework that takes part in control loops by executing Control Loop -Elements in cooperation with the CLAMP Control Loop Runtime. A participant chooses to partake -in control loops, to manage Control Loop Elements for CLAMP, and to receive, send and act on -LCM messages for the CLAMP runtime. - -1.3 Terminology for Properties ------------------------------- - -**Common Properties:** Properties that apply to all Control Loop Instances of a certain Control -Loop Type and are specified when a Control Loop Type is commissioned. - -**Instance Specific Properties:** Properties that must be specified for each Control Loop Instance -and are specified when a Control Loop Instance is Initialized. - -1.4 Concepts and their relationships ------------------------------------- - -The UML diagram below shows the concepts described in the terminology sections above and how -they are interrelated. - -.. image:: images/02-controlloop-concepts.png - -The Control Loop Definition concepts describe the types of things that are in the system. These -concepts are defined at design time and are passed to the runtime in a TOSCA document. The -concepts in the Control Loop Runtime are created by the runtime part of the system using the -definitions created at design time. - -.. _controlloop-capabilities: - -2 Capabilities -============== - -We consider the capabilities of Control Loops at Design Time and Run Time. - -At Design Time, three capabilities are supported: - -#. **Control Loop Element Definition Specification.** This capability allows users to define Control - Loop Element Types and the metadata that can be used on and configured on a Control Loop Element - Type. Users also define the Participant Type that will run the Control Loop Element when it is - taking part in in a control loop. The post condition of an execution of this capability is that - metadata for a Control Loop Element Type is defined in the Control Loop Design Time Catalogue. - -#. **Control Loop Element Definition Onboarding.** This capability allows external users and systems - (such as SDC or DCAE-MOD) to define the metadata that can be used on and configured on a Control - Loop Element Type and to define the Participant Type that will run the Control Loop Element when - it is taking part in in a control loop. The post condition of an execution of this capability - is that metadata for a Control Loop Element Type is defined in the Control Loop Design Time - Catalogue. - -#. **Control Loop Type Definition.** This capability allows users and other systems to create Control - Loop Type definitions by specifying a set of Control Loop Element Definitions from those that - are available in the Control Loop Design Time Catalogue. These Control Loop Elements will - work together to form Control Loops. In an execution of this capability, a user specifies the - metadata for the Control Loop and specifies the set of Control Loop Elements and their Participant - Types. The user also selects the correct metadata sets for each participant in the Control Loop - Type and defines the overall Control Loop Type metadata. The user also specifies the Common - Property Types that apply to all instances of a control loop type and the Instance Specific - Property Types that apply to individual instances of a Control Loop Type. The post condition for - an execution of this capability is a Control Loop definition in TOSCA stored in the Control Loop - Design Time Catalogue. - -.. note:: - Once a Control Loop Definition is commissioned to the Control Loop Runtime and has been - stored in the Run Time Inventory, it cannot be further edited unless it is decommissioned. - - -At Run Time, the following participant related capabilities are supported: - -#. **System Pre-Configuration.** This capability allows participants to register and deregister - with CLAMP. Participants explicitly register with CLAMP when they start. Control Loop Priming - is performed on each participant once it registers. The post condition for an execution of this - capability is that a participant becomes available (registration) or is no longer available - (deregistration) for participation in a control loop. - -#. **Control Loop Priming on Participants.** A participant is primed to support a Control Loop Type. - Priming a participant means that the definition of a control loop and the values of Common - Property Types that apply to all instances of a control loop type on a participant are sent - to a participant. The participant can then take whatever actions it need to do to support - the control loop type in question. Control Loop Priming takes place at participant - registration and at Control Loop Commissioning. The post condition for an execution of this - capability is that all participants in this control loop type are commissioned, that is they - are prepared to run instances of their Control Loop Element types. - - -At Run Time, the following Control Loop Life Cycle management capabilities are supported: - -#. **Control Loop Commissioning:** This capability allows version controlled Control Loop Type - definitions to be taken from the Control Loop Design Time Catalogue and be placed in the - Commissioned Control Loop Inventory. It also allows the values of Common Property Types - that apply to all instances of a Control Loop Type to be set. Further, the Control Loop - Type is primed on all concerned participants. The post condition for an execution of this - capability is that the Control Loop Type definition is in the Commissioned Control Loop - Inventory and the Control Loop Type is primed on concerned participants. - -#. **Control Loop Instance Life Cycle Management:** This capability allows a Control Loop - Instance to have its life cycle managed. - - #. **Control Loop Instance Creation:** This capability allows a Control Loop Instance to be - created. The Control Loop Type definition is read from the Commissioned Control Loop - Inventory and values are assigned to the Instance Specific Property Types defined for - instances of the Control Loop Type in the same manner as the existing CLAMP client does. - A Control Loop Instance that has been created but has not yet been instantiated on - participants is in state UNINITIALIZED. In this state, the Instance Specific Property Type - values can be revised and updated as often as the user requires. The post condition for an - execution of this capability is that the Control Loop instance is created in the - Instantiated Control Loop Inventory but has not been instantiated on Participants. - - #. **Control Loop Instance Update on Participants:** Once the user is happy with the property - values, the Control Loop Instance is updated on participants and the Control Loop Elements - for this Control Loop Instance are initialized or updated by participants using the control - loop metadata. The post condition for an execution of this capability is that the Control - Loop instance is updated on Participants. - - #. **Control Loop State Change:** The user can now order the participants to change the state - of the Control Loop Instance. If the Control Loop is set to state RUNNING, each participant - begins accepting and processing control loop events and the Control Loop Instance is set - to state RUNNING in the Instantiated Control Loop inventory. The post condition for an - execution of this capability is that the Control Loop instance state is changed on - participants. - - #. **Control Loop Instance Monitoring:** This capability allows Control Loop Instances to be - monitored. Users can check the status of Participants, Control Loop Instances, and Control - Loop Elements. Participants report their overall status and the status of Control Loop - Elements they are running periodically to CLAMP. Clamp aggregates these status reports - into an aggregated Control Loop Instance status record, which is available for monitoring. - The post condition for an execution of this capability is that Control Loop Instances are - being monitored. - - #. **Control Loop Instance Supervision:** This capability allows Control Loop Instances to be - supervised. The CLAMP runtime expects participants to report on Control Loop Elements - periodically. The CLAMP runtime checks that periodic reports are received and that each - Control Loop Element is in the state it should be in. If reports are missed or if a - Control Loop Element is in an incorrect state, remedial action is taken and notifications - are issued. The post condition for an execution of this capability is that Control Loop - Instances are being supervised by the CLAMP runtime. - - #. **Control Loop Instance Removal from Participants:** A user can order the removal of a Control - Loop Instance from participants. The post condition for an execution of this capability is - that the Control Loop instance is removed from Participants. - - #. **Control Loop Instance Deletion:** A user can order the removal of a Control Loop Instance - from the CLAMP runtime. Control Loop Instances that are instantiated on participants cannot - be removed from the CLAMP runtime. The post condition for an execution of this capability - is that the Control Loop instance is removed from Instantiated Control Loop Inventory. - -#. **Control Loop Decommissioning:** This capability allows version controlled Control Loop Type - definitions to be removed from the Commissioned Control Loop Inventory. A Control Loop - Definition that has instances in the Instantiated Control Loop Inventory cannot be removed. - The post condition for an execution of this capability is that the Control Loop Type - definition removed from the Commissioned Control Loop Inventory. - -.. note:: - The system dialogues for run time capabilities are described in detail on the - :ref:`System Level Dialogues <system-level-label>` page. - -.. _controlloop-instance-states: - -2.1 Control Loop Instance States --------------------------------- - -When a control loop definition has been commissioned, instances of the control loop can be -created, updated, and deleted. The system manages the lifecycle of control loops and control -loop elements following the state transition diagram below. - -.. image:: images/03-controlloop-instance-states.png - -3 Overall Target Architecture -============================= - -The diagram below shows an overview of the architecture of TOSCA based Control Loop -Management in CLAMP. - -.. image:: images/04-overview.png - -Following the ONAP Reference Architecture, the architecture has a Design Time part and -a Runtime part. - -The Design Time part of the architecture allows a user to specify metadata for participants. -It also allows users to compose control loops. The Design Time Catalogue contains the metadata -primitives and control loop definition primitives for composition of control loops. As shown -in the figure above, the Design Time component provides a system where Control Loops can be -designed and defined in metadata. This means that a Control Loop can have any arbitrary -structure and the Control Loop developers can use whatever analytic, policy, or control -participants they like to implement their Control Loop. At composition time, the user -parameterises the Control Loop and stores it in the design time catalogue. This catalogue -contains the primitive metadata for any participants that can be used to compose a Control -Loop. A Control Loop SDK is used to compose a Control Loop by aggregating the metadata for -the participants chosen to be used in a Control Loop and by constructing the references between -the participants. The architecture of the Control Loop Design Time part will be elaborated in -future releases. - -Composed Control Loops are commissioned on the run time part of the system, where they are -stored in the Commissioned Control Loop inventory and are available for instantiation. The -Commissioning component provides a CRUD REST interface for Control Loop Types, and implements -CRUD of Control Loop Types. Commissioning also implements validation and persistence of incoming -Control Loop Types. It also guarantees the integrity of updates and deletions of Control Loop -Types, such as performing updates in accordance with semantic versioning rules and ensuring that -deletions are not allowed on Control Loop Types that have instances defined. - -The Instantiation component manages the Life Cycle Management of Control Loop Instances and -their Control Loop Elements. It publishes a REST interface that is used to create Control Loop -Instances and set values for Common and Instance Specific properties. This REST interface is -public and is used by the CLAMP GUI. It may also be used by any other client via the public -REST interface. the REST interface also allows the state of Control Loop Instances to be changed. -A user can change the state of Control Loop Instances as described in the state transition -diagram shown in section 2 above. The Instantiation component issues update and state change -messages via DMaaP to participants so that they can update and manage the state of the Control -Loop Elements they are responsible for. The Instantiation component also implements persistence -of Control Loop Instances, control loop elements, and their state changes. - -The Monitoring component reads updates sent by participants. Participants report on the -state of their Control Loop Elements periodically and in response to a message they have -received from the Instantiation component. The Monitoring component reads the contents of -the participant messages and persists their state updates and statistics records. It also -publishes a REST interface that publishes the current state of all Participants, Control -Loop Instances and their Control Loop Elements, as well as publishing Participant and -Control Loop statistics. - -The Supervision component is responsible for checking that Control Loop Instances are correctly -instantiated and are in the correct state (UNINITIALIZED/READY/RUNNING). It also handles -timeouts and on state changes to Control Loop Instances, and retries and rolls back state -changes where state changes failed. - -A Participant is an executing component that partakes in control loops. More explicitly, a -Participant is something that implements the Participant Instantiation and Participant -Monitoring messaging protocol over DMaaP for Life Cycle management of Control Loop Elements. -A Participant runs Control Loop Elements and manages and reports on their life cycle -following the instructions it gets from the CLAMP runtime in messages delivered over DMaaP. - -In the figure above, five participants are shown. A Configuration Persistence Participant -manages Control Loop Elements that interact with the `ONAP Configuration Persistence Service -<https://docs.onap.org/projects/onap-cps/en/latest/overview.html>`_ -to store common data. The DCAE Participant runs Control Loop Elements that manage DCAE -microservices. The Kubernetes Participant hosts the Control Loop Elements that are managing -the life cycle of microservices in control loops that are in a Kubernetes ecosystem. The -Policy Participant handles the Control Loop Elements that interact with the Policy Framework -to manage policies for control loops. A Controller Participant such as the CDS Participant -runs Control Loop Elements that load metadata and configure controllers so that they can -partake in control loops. Any third party Existing System Participant can be developed to -run Control Loop Elements that interact with any existing system (such as an operator's -analytic, machine learning, or artificial intelligence system) so that those systems can -partake in control loops. - -4. Other Considerations -======================= - -.. _management-cl-instance-configs: - -4.1 Management of Control Loop Instance Configurations ------------------------------------------------------- - -In order to keep management of versions of the configuration of control loop instances -straightforward and easy to implement, the following version management scheme using -semantic versioning is implemented. Each configuration of a Control Loop Instance and -configuration of a Control Loop Element has a semantic version with 3 digits indicating -the **major.minor.patch** number of the version. - -.. note:: - A **configuration** means a full set of parameter values for a Control Loop Instance. - -.. image:: images/05-upgrade-states.png - -Change constraints: - -#. A Control Loop or Control Loop Element in state **RUNNING** can be changed to a higher patch - level or rolled back to a lower patch level. This means that hot changes that do not - impact the structure of a Control Loop or its elements can be executed. - -#. A Control Loop or Control Loop Element in state **PASSIVE** can be changed to a higher - minor/patch level or rolled back to a lower minor/patch level. This means that structural - changes to Control Loop Elements that do not impact the Control Loop as a whole can be - executed by taking the control loop to state **PASSIVE**. - -#. A Control Loop or Control Loop Element in state **UNINITIALIZED** can be changed to a higher - major/minor/patch level or rolled back to a lower major/minor/patch level. This means - that where the structure of the entire control loop is changed, the control loop must - be uninitialized and reinitialized. - -#. If a Control Loop Element has a **minor** version change, then its Control Loop Instance - must have at least a **minor** version change. - -#. If a Control Loop Element has a **major** version change, then its Control Loop Instance - must have a **major** version change. - -4.2 Scalability ---------------- - -The system is designed to be inherently scalable. The CLAMP runtime is stateless, all state -is preserved in the Instantiated Control Loop inventory in the database. When the user -requests an operation such as an instantiation, activation, passivation, or an uninitialization -on a Control Loop Instance, the CLAMP runtime broadcasts the request to participants over -DMaaP and saves details of the request to the database. The CLAMP runtime does not directly -wait for responses to requests. - -When a request is broadcast on DMaaP, the request is asynchronously picked up by participants -of the types required for the Control Loop Instance and those participants manage the life -cycle of its control loop elements. Periodically, each participant reports back on the status -of operations it has picked up for the Control Loop Elements it controls, together with -statistics on the Control Loop Elements over DMaaP. On reception of these participant messages, -the CLAMP runtime stores this information to its database. - -The participant to use on a control loop can be selected from the registered participants -in either of two ways: - -**Runtime-side Selection:** The CLAMP runtime selects a suitable participant from the list of -participants and sends the participant ID that should be used in the Participant Update message. -In this case, the CLAMP runtime decides on which participant will run the Control Loop Element -based on a suitable algorithm. Algorithms could be round robin based or load based. - -**Participant-side Selection:** The CLAMP runtime sends a list of Participant IDs that may be used -in the Participant Update message. In this case, the candidate participants decide among -themselves which participant should host the Control Loop Element. - -This approach makes it easy to scale Control Loop life cycle management. As Control Loop -Instance counts increase, more than one CLAMP runtime can be deployed and REST/supervision -operations on Control Loop Instances can run in parallel. The number of participants can -scale because an asynchronous broadcast mechanism is used for runtime-participant communication -and there is no direct connection or communication channel between participants and CLAMP -runtime servers. Participant state, Control Loop Instance state, and Control Loop Element -state is held in the database, so any CLAMP runtime server can handle operations for any -participant. Because many participants of a particular type can be deployed and participant -instances can load balance control loop element instances for different Control Loop Instances -of many types across themselves using a mechanism such as a Kubernetes cluster. - - -4.3 Sandboxing and API Gateway Support --------------------------------------- - -At runtime, interaction between ONAP platform services and application microservices are -relatively unconstrained, so interactions between Control Loop Elements for a given Control -Loop Instance remain relatively unconstrained. A -`proposal to support access-controlled access to and between ONAP services -<https://wiki.onap.org/pages/viewpage.action?pageId=103417456>`_ -will improve this. This can be complemented by intercepting and controlling services -accesses between Control Loop Elements for Control Loop Instances for some/all Control -Loop types. - -API gateways such as `Kong <https://konghq.com/kong/>`_ have emerged as a useful technology -for exposing and controlling service endpoint access for applications and services. When a -Control Loop Type is onboarded, or when Control Loop Instances are created in the Participants, -CLAMP can configure service endpoints between Control Loop Elements to redirect through an -API Gateway. - -Authentication and access-control rules can then be dynamically configured at the API gateway -to support constrained access between Control Loop Elements and Control Loop Instances. - -The diagram below shows the approach for configuring API Gateway access at Control Loop -Instance and Control Loop Element level. - -.. image:: images/06-api-gateway-sandbox.png - -At design time, the Control Loop type definition specifies the type of API gateway configuration -that should be supported at Control Loop and Control Loop Element levels. - -At runtime, the CLAMP can configure the API gateway to enable (or deny) interactions between -Control Loop Instances and individually for each Control Loop Element. All service-level -interactions in/out of a Control Loop Element, except that to/from the API Gateway, can be -blocked by networking policies, thus sandboxing a Control Loop Element and an entire Control -Loop Instance if desired. Therefore, a Control Loop Element will only have access to the APIs -that are configured and enabled for the Control Loop Element/Instance in the API gateway. - -For some Control Loop Element Types the Participant can assist with service endpoint -reconfiguration, service request/response redirection to/from the API Gateway, or -annotation of requests/responses. - -Once the Control Loop instance is instantiated on participants, the participants configure -the API gateway with the Control Loop Instance level configuration and with the specific -configuration for their Control Loop Element. - -Monitoring and logging of the use of the API gateway may also be provided. Information and -statistics on API gateway use can be read from the API gateway and passed back in monitoring -messages to the CLAMP runtime. - -Additional isolation and execution-environment sandboxing can be supported depending on the -Control Loop Element Type. For example: ONAP policies for given Control Loop Instances/Types -can be executed in a dedicated PDP engine instances; DCAE or K8S-hosted services can executed -in isolated namespaces or in dedicated workers/clusters; etc.. - - -5 APIs and Protocols -==================== - -The APIs and Protocols used by CLAMP for Control Loops are described on the pages below: - -#. :ref:`System Level Dialogues <system-level-label>` -#. :ref:`The CLAMP Control Loop Participant Protocol <controlloop-participant-protocol-label>` -#. :ref:`REST APIs for CLAMP Control Loops <controlloop-rest-apis-label>` - - -6 Design and Implementation -=========================== - -The design and implementation of TOSCA Control Loops in CLAMP is described for each executable entity on the pages below: - -#. :ref:`The CLAMP Control Loop Runtime Server <clamp-controlloop-runtime>` -#. :ref:`CLAMP Control Loop Participants <clamp-controlloop-participants>` -#. :ref:`Managing Control Loops using The CLAMP GUI <clamp-gui-controlloop>` - -End of Document |