[Kubernetes][API Server] Re-add removed visualisation

[tetianakravchenko]

Before enabling TSDB some of visualisations were using sum as an aggregation formula.

Example: One of the visualizations used the formula (sum(kubernetes.apiserver.request.duration.up.sum)/sum(kubernetes.apiserver.request.duration.up.count))/1000. The field kubernetes.apiserver.request.duration.up.* has 8 different labels, and we used to have it broken down by the kubernetes.apiserver.request.resource.

Both these metrics used in the formula are of type counter. Since now sum is not supported aggregation for counter, it should be changed to either last_value or max aggregation. However, we cannot reproduce the same visualization - request duration per resource - with these aggregations, since it is not possible to cluster the data according to a specific label.

Affected visualizations were removed in https://github.com/elastic/integrations/pull/617.

Few options:

• we split the visualization by the 8 fields
  • BUT: it will overwhelm the visualization and might be not informative
  • BUT2: maximum are supported 4 fields for breaking down
• rethink those visualizations, come up with different representation
• re-discuss support of sum (?)
• drop those visualizations

[botelastic[bot]]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!