LOG Meeting Minutes 2017-08-22

Minutes:

1. Filebeat deployment:
1. OOM deployment is proceeding with one Filebeat container per pod or (as a daemonset) per container. 
2. Logs are initially being written to non-persistent volumes, making them vulnerable to loss. This is a provisional configuration only.
3. Both were decisions by the architects for the implementation teams.
2. Impact of Zipkin:
1. Confirmed to require in-container probes (→ ONAP-wide classpath changes), collector agents.
2. That's seen as prohibitive. Will proceed with REST and MDC conventions for now.
3. Tracing:
1. Continue to improve transactionID propagation.
2. Limitations of X-FromAppID. 
3. Intention is to identify and disambiguate invocations between components.
4. Suggestion (as per diagram attached to last week's minutes):
1. Generate an invocationID per service call, logged as MDC. 
2. Pass invocationID in REST invocations as per transactionID.
3. Use Markers to:
1. Report relationship between caller invocationID and invoked invocationID. 
2. Report return and/or exit.
3. (Possibly other stuff like async execution).
4. What this achieves:
1. Minimal impact; conventions, but no API changes.
2. All of the above is captured in the Elastic Stack index, allowing an invocation graph to be construction.
5. Question (Horace Ji):
   1. Does a suitable MDC already exist? 
   2. Usage is inconsistent, so I think we all agreed it's risky, and probably saves to invent something new. 
   3. (With MDCs logged as name-value pairs, there's no great cost to defining a new MDC).
6. Suggestion (Dave Williamson):
1. Record relationship between caller and invoked elements at the caller end.
2. Then:
   1. The invoking component issues an invocationID during invocation. (And records nothing new).
   2. The invoked component just sets the invocationID MDC wherever it presently sets the transactionID MDC.
7. Suggestions (Lee Breslau):
1. Use EELF audit log to record entry.
2. Use EELF metric log to record exit.
4. Logging wrappers/abstractions between the application and EELF. (Which we missed, sorry).

Actions:

• Update on Filebeat deployment (Luke Parker) 
• M3 (API freeze) debrief (Luke Parker).
• Logging abstractions (Dave Williamson).
• Draft updated logging guide. (Luke Parker).
• Continue discussion of tracing options:
  • Suggestions above. 
  • Persisting invocationID and transactionID in cases like where execution may be deferred (e.g. BPMN). 
    • (I think this supports Dave's suggestion).