KAFKA-19865: Document queues metrics changes in ops.html

[JimmyWang6]

From KAFKA-19865，
This PR introduces documentation support for monitoring Kafka share groups and share consumers, including new metric registries and documentation updates. The changes add new classes to define and expose share group metrics, and update the documentation to describe these metrics and how to monitor them.

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[JimmyWang6]

Not quite sure if we need to show the DelayedOperationPurgatory metrics in the documentation, as it doesn't only apply to share group.

[apoorvmittal10]

I think we should mention this. I do only see that following is defined in Kafka documentation kafka.server:type=DelayedRemoteFetchMetrics,name=ExpiresPerSec,topic=([-.\w]+) and not for others. Also I see kafka.server:type=DelayedOperationPurgatory,name=PurgatorySize,delayedOperation has been declared separately for Produce and Fetch then we should follow the similar pattern.

[JimmyWang6]

Hi @apoorvmittal10 @AndrewJSchofield, gentle ping on this. Please take a look when you get a chance. Thanks!

[apoorvmittal10]

Thanks for the PR @JimmyWang6. mbean miss the metric name. In Kafka documentation I can see other metrics do define the mbean correctly.

[apoorvmittal10]

In the PR we have just client metrics as sub resource under Share Group Montioring, but should we have coordinator as well which can contain group coordinator and share coordinator metrics. The other reason for this suggestion is that coordinator metrics are not yammer and broker ones are, hence the metrics name casing differs. Hence the table of metrics look odd with differnt casing so if we have the respective sections then it ll make sense. @AndrewJSchofield wdyt?

[AndrewJSchofield]

In the PR we have just client metrics as sub resource under Share Group Montioring, but should we have coordinator as well which can contain group coordinator and share coordinator metrics. The other reason for this suggestion is that coordinator metrics are not yammer and broker ones are, hence the metrics name casing differs. Hence the table of metrics look odd with differnt casing so if we have the respective sections then it ll make sense. @AndrewJSchofield wdyt?

I agree. It looks a bit odd with the different types of metrics mixed up together.