K8S Processor: configure tag name with source of the IP address

[pmm-sumo]

Is your feature request related to a problem? Please describe.

It would be good to introduce some flexibility into name of the tag which includes source IP. Currently, following tags are being considered:

• k8s.pod.ip - typically added when passthrough mode is employed
• ip - legacy passthrough mode tag, also used by some clients (e.g. Jaeger)
• host.hostname - used by some metrics sources (e.g. Prometheus) - currently enabled only for metrics

Describe the solution you'd like
Introduce following configuration entry:

• ip_extraction_by_attribute_labels - by default [ip, k8s.pod.ip, host.hostname]

Describe alternatives you've considered

Perhaps host.hostname can be used as an attribute extracted by default for metrics only (which would match the current behaviour, though make the code it bit more complicated)

Additional context
N/A

[owais]

We currently support all three of these in some form. Are there other examples users might want to add? If the list is well-known, may be we can support them out of the box without a config option?

[pmm-sumo]

We currently support all three of these in some form. Are there other examples users might want to add? If the list is well-known, may be we can support them out of the box without a config option?

My thinking is that especially in case of logs there might be some custom tags containing the source IP address (and to make things more complex, at a record level)

On the other hand, it might be premature to solve this problem now and we should get a set of real-life examples before starting working on this one. I am going to research a bit more. E.g. perhaps a capability to tag by podName might be needed for log usecases. Seems to be a good topic for discussion during the next SIG.

[pmm-sumo]

I have prepared a doc with my research and some context into this: https://docs.google.com/document/d/1QlFbXz0eQUaKXK1WrnEs3VqRkcPD2RAdXJdJMjnOSd8/edit# - also #1146 contains some alternative proposal of the config entry

[pmm-sumo]

Closing in favor of #1146