Related Jira(s)

Issues and Decisions

Description

1. Define scenarios which cause a CM Handle to go stale
2. Implement changes to support tracking of CM Handle Freshness/Staleness

What might trigger a cmhandle to go to STALE?

1. dmi plugin identifies that the device is no longer contactable
2. dmi plugin identifies that an underlying device manager managing the device (node) is out of sync with the device itself. 

Requirements

Functional

Error Handling

Capabilities

1. re-registration, once a day, same requirement as first time registration
2. single node heart beat failures 30,000 / minute per instance
   1. Kafka should be able handle 2 instances i.e. 60K notifications in one minute
   2. What is expected/realistic here from CPS-NCMP see open issue #1

Scope

1. Currently only supporting NONE and COMPLETE. PARTIAL and POOR may be added later as below.

Reregistration

1. This process occurs when the DMI Plugin Availability is down and then comes back up.
   
2. NCMP makes a synchronous call to the DMI Plugin (New Audit Endpoint) to trigger a reregistration
   
3. DMI Plugin then reregisters its CMHandles with NCMP (new reregistaration Endpoint?)
   
4. NCMP then compares the CMHandles which are being reregistered with the CMHandles which already exist.
   
5. CMHandles which are in NCMP but not in DMI reregistration request are kept as trust level none
   
6. What happens if there is conflict between the old and new properties of a CMHandle, just take the new properties?
   
7. New CMHandles could be registered

High Level Interactions

{
  "dmiPlugin": "my-dmi-plugin",
  "dmiModelPlugin": "my-dmi-model-plugin",
  "cmHandles": [
    {
      "cmHandle": "my-cm-handle",
      "publicCmHandleProperties": {
        "key": "my-property"
      },
      "cmHandleProperties": {
        "key": "my-property"
      }
    },
    {
      "cmHandle": "my-cm-handle",
      "publicCmHandleProperties": {
        "key": "my-property"
      },
      "cmHandleProperties": {
        "key": "my-property"
      }
    }
  ],
  "dmiDataPlugin": "my-dmi-data-plugin"
}

Managing TrustLevels

DMI Plugins

1. NCMP is checking every DMI Plugin for health at interface 1 every 30 seconds using the DMI Trust Map
2. IF a DMI Plugin goes down, that DMI Plugin's trust level is updated to NONE in the DMI Trust Map
3. IF a DMI Plugin comes back up, NCMP requests that DMI Plugin to do a reregistration via interface 2
   1. That DMI reregisters itself using interface 3
   2. NCMP analyses the registration and compares the CMHandles it knows about to the CMHandles which have been reregistered, any CMHandles which did exist and are not reregistered are now added to the untrustworthy CMHandles Map. Existing CMHandles are updated and new ones are created.
   3. After the reregistration is complete, the DMI Plugin TrustMap is updated to set the trust level for that DMI to complete.

CMHandles HB

1. It is the responsibility of the DMI Plugins to update NCMP about the HBs of CMHandles
2. Through interface 4, DMI Plugins will provide a kafka event on the changing of trustworthiness state of a CMHandle.
   1. NCMP receives this event and updates the Untrustworthy CMHandles Map accordingly
3. Needs to be able to handle a throughput of 30,000 State changes per minute

Reading Trust Level

1. Body of request to be discussed, Will the request provide a DMI or a list of CMHandles?
2. Interface 5
3. NCMP will first check DMI Trust Map for the CMHandle
   1. If that DMI which is managing the CMHandle is marked as untrustworthy then we return NONE without checking the Untrustworthy CMHandles Map
   2. If that DMI is trustworthy, we check the individual CMHandles Map, if the CMHandle is in the Map then return NONE.
4. Logically IF (DMITrustMap.getDMIPlugin.getTrustLevel ==  NONE) Return NONE
   1. ELSE (IF UntrustworthyCMHandlesMap.getDMIPlugin.contains(CMHandle) RETURN NONE
   2. ELSE return COMPLETE