Add support to monitor CoreDNS

[exekias]

Metricbeat Module / Dataset release checklist

Implement a new module to monitor CoreDNS. This is probably similar to what we did for apiserver: #7059

Modules

For a metricset to go GA, the following criterias should be met:

• Supported versions are documented
• System tests exist
• Automated checks that all fields are documented
• Documentation
• Fields follow ECS and naming conventions
• Dashboards exists [Metricbeat] CoreDNS module: Add Kibana Dashboard #11619
• Example data.json exists and an automated way to generate it exists (go test -data)
• Test environment in Docker exist for integration tests
• Add Data UI

[ChrsMark]

Hey @exekias!
Is anyone working on this already? @ioandr and me would be happy to implement this!

In this, are you considering this as a standalone metricebeat module, or a metricset under kubernetes' module?

This integration seems really interesting now that CoreDNS is the default cluster DNS server of k8s.

[ruflin]

Hi @ChrsMark Nobody is working on this yet. I would see this as a separate module like Nats.

[ChrsMark]

Perfect! We will give it a try with @ioandr.

[ruflin]

@ChrsMark Great, thank you 🎉

[ruflin]

Implementation started in #10585

[ChrsMark]

Hello, it would be nice to have the checklist updated!

From what I can see the only thing left is the dashboard?

[ruflin]

@ChrsMark Updated. Agree that Dashboards are missing and I added one more item to the list: Add Data UI.

[ioandr]

Hey @ruflin,

I plan to take up the Dasbhoard and @ChrsMark can move on with the Kibana Tutorial (Data UI).