Deprecate Alerts for Managed Prometheus

Proposal

%13.11

  1. Add deprecation notice in https://docs.gitlab.com/ee/operations/metrics/alerts.html#managed-prometheus-instances

"%13.12"

  1. Add banner on top of Metrics page to alert users of deprecation of alerts if they are currently on Managed Prometheus. Issue: #328774 (closed)
  2. Update runbooks docs for externally managed prometheus.

%14.0

  1. Remove Alert setup menu (click on ellipsis on each menu)
  2. Remove display of existing alerts from UI (See Existing alert ui)
  3. Drop the processing of the managed ones in the NotifyService.
  4. Remove the deprecation notice on the metrics dashboard when the above is complete

Motivation

Managed Prometheus is deprecated since 13.7 and will be removed in GitLab 14.0 (&4280)

Questions

Question Answer Follow-Up Issue
How many users will be impacted by the deprecation?
The deprecation of alerts in one milestone seems abrupt for users who depend on this? How do we notify users that this is happening?
Should we fully remove the alert/runbook features if we plan to add functionality back later? Could we change the underlying logic instead of deprecating everything?
Does the feature have to be fully deprecated in %14.0 or do we have any additional time? 2 milestones?
Will existing alerts be migrated? Since we’re not removing the clusters the alerts on prometheus will still be processed correctly on GitLab if we don’t remove the data.

References

Existing alert UI

Screen_Shot_2021-04-15_at_11.26.28_AM

/cc @kbychu @seanarnold @crystalpoole

Edited by Amelia Bauerly