Multiple circuit breakers emit the same stat

[jmuia]

Title: Multiple circuit breakers emit the same stat

Description:
It appears that for the HTTP/2 connection pool, the cluster.<name>.upstream_rq_pending_overflow stat is emitted when two different circuit breakers are hit: max_requests [0] and max_pending_requests [1].

This has the potential to be confusing, particularly if the the thresholds are configured to be different.

I believe this was introduced in #4917

[0] https://github.com/envoyproxy/envoy/blob/2fe5b8a/source/common/http/http2/conn_pool.cc#L92
[1] https://github.com/envoyproxy/envoy/blob/2fe5b8a/source/common/http/http2/conn_pool.cc#L132

[mattklein123]

This is a duplicate of #9215 or very similar. I agree this is extremely confusing and something I would like to fix. cc @tonya11en. Can we potentially merge this into #9215 if that issue does not cover this also?

[jmuia]

I think it's good to merge into #9215.

The only requirement here is that there needs to be a separate stat for requests overflow and for pending requests overflow. Since the HTTP/1 connection pool already has this, I suspect when the work in #9125 is done the HTTP/2 connection pool will also have it.

Thanks!

[stale]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or other activity occurs. Thank you for your contributions.

[stale]

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