[clusteragent/autoscaling] Add telemetry metrics for autoscaling controller

[jennchenn]

What does this PR do?

Add the following telemetry metrics around the autoscaling controller:

• autoscaling.queue_*
• autoscaling.status_conditions
• workload_autoscaling.horizontal_scaling
• workload_autoscaling.vertical_scaling

Motivation

Improve monitoring and debugging.

Additional Notes

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

Deploy Cluster Agent with autoscaling controller activated, autoscaling.* metrics should be available on Prom endpoint (localhost:5000/metrics).
With Agent >= 7.57, metrics should also be scrape by DCA integration

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 38014940-d618-4655-a287-e9a5434b8577 Metrics dashboard Target profiles

Baseline: 6108bcf
Comparison: c6f367c

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

No significant changes in experiment optimization goals

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

There were no significant changes in experiment optimization goals at this confidence level and effect size tolerance.

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	links
➖	otel_to_otel_logs	ingress throughput	+0.82	[+0.00, +1.63]	Logs
➖	idle	memory utilization	+0.31	[+0.28, +0.35]	Logs
➖	file_tree	memory utilization	+0.29	[+0.23, +0.35]	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.01, +0.01]	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.00, +0.00]	Logs
➖	basic_py_check	% cpu utilization	-0.08	[-2.86, +2.70]	Logs
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	-0.43	[-1.31, +0.46]	Logs
➖	pycheck_1000_100byte_tags	% cpu utilization	-0.67	[-5.46, +4.12]	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-1.69	[-14.22, +10.84]	Logs

Explanation

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

[pr-commenter]

Test changes on VM

Use this command from test-infra-definitions to manually test this PR changes on a VM:

inv create-vm --pipeline-id=41250820 --os-family=ubuntu

Note: This applies to commit c6f367c

[ogaca-dd]

LGTM for files owned by ASC

[vboulineau]

/merge

[dd-devflow]

🚂 MergeQueue: pull request added to the queue

The median merge time in main is 22m.

Use /merge -c to cancel this operation!