[Breaking change] Removal of monitoring migrate alerts endpoint

[jbaiera]

Removal of the /_monitoring/migrate/alerts endpoint.

Which release will ship the breaking change?

8.0

Is this a Kibana or Elasticsearch breaking change?

Elasticsearch

Describe the change. How will it manifest to users?

This endpoint was added last year as a way for Kibana to request the removal of default Monitoring alerts from Elasticsearch so that they may be replaced by Kibana Alerting. In 8.0 we will no longer be installing alerts with Monitoring and so this endpoint is being targeted for removal.

How many users will be affected?

This is an API that is primarily meant for consumption within Kibana, and thus a majority of user deployments are likely to be affected.

Are there any edge cases?

The endpoint will be deprecated in 7.16 and removed in 8.0, which means that rolling upgrades are a concern.

[For Kibana deprecations] Can the change be registered with the Kibana deprecation service?

This does not strike me as a deprecation service issue.

[For Elasticsearch deprecations] Can the Upgrade Assistant make the migration easier for users? Please explain the proposed solution in as much detail as possible.

Upgrade Assistant is not applicable

Test Data

Cross links

elastic/elasticsearch#50770

[elasticmachine]

Pinging @elastic/stack-monitoring (Team:Monitoring)

[jbaiera]

cc: @jasonrhodes

[jbaiera]

We are making some course changes here. This will no longer be required for 8.0, but will be needed at some point after then. I'll update the issue description.

[jbaiera]

Actually, I'll just close this for now. The time horizon for this deprecation and removal is going to be quite a bit longer than originally thought and we can address it when it gets closer.