[Etcd] Deprecation of V2 API and related datasets

[agithomas]

ETCD Integration is currently in Beta.

The existing integration of ETCD makes use of HTTP V2 API and Prometheus Endpoint. Below are the details of the implementation

Datastream Name	Implementation Method
leader	V2 API
metrics	Prometheus endpoint
self	V2 API
store	V2 API

Key points

• The current stable version of ETCD is 3.5 . Version 3.6 is in draft state.
• API V2 is not enabled by default in ETCD version 3.5 . It can be enabled by setting the environment variable
• API V2 will be disabled as part of 3.6 . Below are the lines from the 3.6 release plan.

I made an attempt below to link the metrics that were part of the existing ETCD datasets (leader, self, store) and equivalent metrics in the V3 prometheus metrics.

V2 field	V3 Metric
leader.follower.latency.ms	peer_round_trip_time_seconds
leader.follower.success_operations , leader.follower.failed_operations	proposals_committed_total, proposals_applied_total, proposals_pending, proposals_failed_total, has_leader ( All fields are existing in metrics ds)
self.uptime, self.start_time	process_start_time_seconds
self.recv.*, self.send	etcd_network_peer_received_bytes_total, etcd_network_peer_sent_bytes_total, etcd_network_peer_round_trip_time_seconds_bucket, peer_sent_bytes_total, peer_received_bytes_total, peer_sent_failures_total, peer_received_failures_total, peer_round_trip_time_seconds
store.gets, store.sets, store.delete, store.update, store.create	etcd_debugging_store_writes_total, etcd_debugging_store_expires_total, etcd_debugging_store_reads_total, etcd_debugging_store_watchers

[agithomas]

Task :

• ETCD 3.0 - 3.5 supports V2 APIs. Should V2 API-based dataset be supported considering below mentioned points

  • 3.5 is the current stable version.
  • V2 API output is derived from V3 metrics. Please refer to the above screenshot
  • There exist no 1-1 mapping between V2 API metrics and V3 metrics.

• Validate the necessity of including these metrics additionally as part of metrics dataset considering v2 API based datasets are decommissioned

• Validate the necessity of adding additional dashboard panels based on the selected metrics from Task 2 , mentioned above.

[agithomas]

@lalit-satapathy , @SubhrataK , @gpop63 , please share your thoughts on the Tasks, mentioned above , after going through the description of the issue.

[agithomas]

My recommendations are below

• Deprecate all datastreams based on V2 APIs
• Have additional V2 equivalent metrics collected as part of metrics datastream
• Have two panels additionally included in the Dashboard to show
  • proposals_* metrics
  • etcd_debugging_store* metrics