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This dialogue is used as a heartbeat mechanism for participants, to monitor the status of Control Loop Elements, and to gather statistics on control loops. The ParticipantStatus message is sent periodically by each participant. The reporting interval for sending the message is configurable.
Messages
The CLAMP Control Loop Participant Protocol uses the following messages. The descriptions below give an overview of each message. For the precise definition of the messages, see the CLAMP code at: https://github.com/onap/policy-clamp/tree/master/models/src/main/java/org/onap/policy/clamp/controlloop/models/messages/dmaap/participant.
Participant Registration
Participant Registration Ack
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Control Loop State Change
Participant Status
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This page is updated for Istanbul to this point. |
Participant handles 4 types of messages
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2. Control Loop Update: This message creates the control loop elements and brings them from UNINITIALIZED to PASSIVE state.
ControlLoopUpdate message contains full ToscaServiceTemplate describing all components participating in a control loop.
This acts as a template for any control loop to be created according to the template.
When participant-intermediary receives this message, it triggers creation of policy-types and policies in Policy-Framework by Policy-Participant,
and deploys DCAE from DCAE-participant
3. Control Loop State change: This message is used to order a state change in control loop element.
Runtime can order one of the following ordered states.
UNINITIALIZED : The control loop or control loop element should become uninitialized on participants, it should not exist on participants.
PASSIVE : The control loop or control loop element should initialized on the participants and be passive, that is,
it is not handling control loop messages yet.
RUNNING : The control loop or control loop element should running and is executing control loops. Once any of above states are ordered, then control loop element transitions into
UNINITIALIZED : The control loop or control loop element is not initialized on participants, it does not exist on participants.
UNINITIALIZED2PASSIVE : The control loop or control loop element is changing from uninitialized to passive,
it is being initialized onto participants.
PASSIVE : The control loop or control loop element is initialized on the participants but is passive, that is, it is not
handling control loop messages yet.
PASSIVE2RUNNING : The control loop or control loop element is changing from passive to running,
the participants are preparing to execute control loops.
RUNNING : The control loop or control loop element is running and is executing control loops.
RUNNING2PASSIVE : The control loop or control loop element is completing execution of current control loops but
will not start running any more control loops and will become passive.
PASSIVE2UNINITIALIZED : The control loop or control loop element is changing from passive to uninitialized,
the control loop is being removed from participants
4. Participant Healthcheck: This message is used to learn the health status of a participant.
As a response to any of the above message participant returns a Participant Status message, holding respective message response.
Runtime receives Participant Status message and stores relevant information in database, Or performs respective actions.
Participant Pass Through
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The information in this section is speculative |
For Control Loop Elements on certain participants, there may be a need to provide domain specific directives to a Control Loop Element or elements such as a microservice or a collection of microservices while a Control Loop Instance is running.
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