[autoscaling] HPA migration controller for DPA workload autoscaler

[clamoriniere]

Summary

• Adds a new HPA migration controller (controller_hpa_migration.go) that detects existing HPAs targeting the same workload as a DPA, imports their configuration (metrics, replica bounds, custom queries) as DPA objectives/constraints, neutralises the HPA by setting its replica count to a sentinel value, and adds an HPAMigrationFinalizer to the DPA. On DPA deletion the finalizer handler restores the HPA to its original state.
• Adds an admission webhook (hpa_webhook.go) that intercepts UPDATE operations on HPA resources managed by a DPA, reverts any spec change to keep the HPA neutralised, and surfaces a warning to the user.
• Fixes profile template update overwriting HPA-imported objectives: RestoreHPAImportedSpec() is called before writing an updated profile spec to Kubernetes so one-shot-imported fields survive profile hash changes.
• Fixes %%tag_kube_cluster_name%% / %%env_VAR%% placeholders being stored raw in the DPA spec: ResolveMetricQuery() (exported from externalmetrics/model) is now called at import time inside resolveExternalMetricConfig().

Test plan

• Unit tests for HPAWebhook in hpa_webhook_test.go (8 tests, all passing)
• Unit tests for RestoreHPAImportedSpec in pod_autoscaler_test.go
• Unit tests for ResolveMetricQuery in utils_test.go and template variable resolution in controller_hpa_migration_test.go
• Manual validation on a kind cluster (clamoriniere-hpa-migration) with the Datadog Operator and a real HPA targeting an nginx deployment

🤖 PR description and code assisted by Claude:claude-sonnet-4-6

[datadog-prod-us1-6]

🎯 Code Coverage (details)
• Patch Coverage: 52.94%
• Overall Coverage: 50.27% (+0.00%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 79ae686 | Docs | Datadog PR Page | Give us feedback!}

[dd-octo-sts]

Files inventory check summary

File checks results against ancestor 9d5f741f:

Results for datadog-agent_7.80.0~devel.git.502.79ae686.pipeline.111614420-1_amd64.deb:

No change detected

[dd-octo-sts]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor 9d5f741
📊 Static Quality Gates Dashboard
🔗 SQG Job

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	docker_cluster_agent_amd64	+80.31 KiB (0.04% increase)	206.607 → 206.685 → 207.600
✅	docker_cluster_agent_arm64	+64.32 KiB (0.03% increase)	220.634 → 220.697 → 221.150

30 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64	742.198 MiB
✅	agent_deb_amd64_fips	700.272 MiB
✅	agent_heroku_amd64	309.139 MiB
✅	agent_rpm_amd64	742.182 MiB
✅	agent_rpm_amd64_fips	700.256 MiB
✅	agent_rpm_arm64	720.111 MiB
✅	agent_rpm_arm64_fips	681.281 MiB
✅	agent_suse_amd64	742.182 MiB
✅	agent_suse_amd64_fips	700.256 MiB
✅	agent_suse_arm64	720.111 MiB
✅	agent_suse_arm64_fips	681.281 MiB
✅	docker_agent_amd64	802.440 MiB
✅	docker_agent_arm64	805.210 MiB
✅	docker_agent_jmx_amd64	993.360 MiB
✅	docker_agent_jmx_arm64	984.909 MiB
✅	docker_cws_instrumentation_amd64	7.142 MiB
✅	docker_cws_instrumentation_arm64	6.689 MiB
✅	docker_host_profiler_amd64	301.102 MiB
✅	docker_host_profiler_arm64	312.623 MiB
✅	docker_dogstatsd_amd64	39.492 MiB
✅	docker_dogstatsd_arm64	37.690 MiB
✅	dogstatsd_deb_amd64	30.145 MiB
✅	dogstatsd_deb_arm64	28.279 MiB
✅	dogstatsd_rpm_amd64	30.145 MiB
✅	dogstatsd_suse_amd64	30.145 MiB
✅	iot_agent_deb_amd64	44.462 MiB
✅	iot_agent_deb_arm64	41.442 MiB
✅	iot_agent_deb_armhf	42.179 MiB
✅	iot_agent_rpm_amd64	44.462 MiB
✅	iot_agent_suse_amd64	44.462 MiB

On-wire sizes (compressed)

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	+11.05 KiB (0.01% increase)	175.732 → 175.743 → 179.160
✅	agent_deb_amd64_fips	-19.77 KiB (0.01% reduction)	167.436 → 167.417 → 174.440
✅	agent_heroku_amd64	-5.01 KiB (0.01% reduction)	74.980 → 74.975 → 80.310
✅	agent_rpm_amd64	+12.52 KiB (0.01% increase)	177.767 → 177.779 → 182.080
✅	agent_rpm_amd64_fips	+22.16 KiB (0.01% increase)	168.739 → 168.761 → 174.140
✅	agent_rpm_arm64	+16.43 KiB (0.01% increase)	159.797 → 159.813 → 163.610
✅	agent_rpm_arm64_fips	-37.86 KiB (0.02% reduction)	152.118 → 152.081 → 156.850
✅	agent_suse_amd64	+12.52 KiB (0.01% increase)	177.767 → 177.779 → 182.080
✅	agent_suse_amd64_fips	+22.16 KiB (0.01% increase)	168.739 → 168.761 → 174.140
✅	agent_suse_arm64	+16.43 KiB (0.01% increase)	159.797 → 159.813 → 163.610
✅	agent_suse_arm64_fips	-37.86 KiB (0.02% reduction)	152.118 → 152.081 → 156.850
✅	docker_agent_amd64	neutral	268.254 MiB → 272.990
✅	docker_agent_arm64	neutral	255.251 MiB → 261.470
✅	docker_agent_jmx_amd64	neutral	336.898 MiB → 341.610
✅	docker_agent_jmx_arm64	neutral	319.880 MiB → 326.050
✅	docker_cluster_agent_amd64	+22.37 KiB (0.03% increase)	72.424 → 72.446 → 73.460
✅	docker_cluster_agent_arm64	+25.63 KiB (0.04% increase)	67.886 → 67.911 → 68.680
✅	docker_cws_instrumentation_amd64	neutral	2.999 MiB → 3.330
✅	docker_cws_instrumentation_arm64	neutral	2.729 MiB → 3.090
✅	docker_host_profiler_amd64	neutral	110.736 MiB → 125.600
✅	docker_host_profiler_arm64	neutral	105.084 MiB → 120.000
✅	docker_dogstatsd_amd64	neutral	15.286 MiB → 15.870
✅	docker_dogstatsd_arm64	neutral	14.597 MiB → 14.890
✅	dogstatsd_deb_amd64	neutral	7.976 MiB → 8.830
✅	dogstatsd_deb_arm64	neutral	6.856 MiB → 7.750
✅	dogstatsd_rpm_amd64	neutral	7.987 MiB → 8.840
✅	dogstatsd_suse_amd64	neutral	7.987 MiB → 8.840
✅	iot_agent_deb_amd64	neutral	11.700 MiB → 13.210
✅	iot_agent_deb_arm64	neutral	9.997 MiB → 11.620
✅	iot_agent_deb_armhf	neutral	10.209 MiB → 11.780
✅	iot_agent_rpm_amd64	neutral	11.721 MiB → 13.230
✅	iot_agent_suse_amd64	neutral	11.721 MiB → 13.230

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 909ad3f0-ec59-4ff8-916a-87fefc6e140a

Baseline: 9d5f741
Comparison: 79ae686
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	+1.98	[-0.99, +4.94]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	+1.98	[-0.99, +4.94]	1	Logs
➖	quality_gate_logs	% cpu utilization	+1.57	[+0.60, +2.54]	1	Logs bounds checks dashboard
➖	docker_containers_memory	memory utilization	+1.16	[+1.03, +1.30]	1	Logs
➖	file_tree	memory utilization	+0.68	[+0.63, +0.73]	1	Logs
➖	ddot_metrics_sum_delta	memory utilization	+0.26	[+0.07, +0.44]	1	Logs
➖	quality_gate_metrics_logs	memory utilization	+0.23	[-0.01, +0.48]	1	Logs bounds checks dashboard
➖	ddot_logs	memory utilization	+0.15	[+0.09, +0.20]	1	Logs
➖	ddot_metrics_sum_cumulative	memory utilization	+0.08	[-0.07, +0.24]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.04	[-0.36, +0.44]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.01	[-0.08, +0.11]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.20, +0.20]	1	Logs
➖	ddot_metrics	memory utilization	-0.01	[-0.20, +0.18]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	-0.04	[-0.48, +0.41]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	-0.06	[-0.62, +0.51]	1	Logs
➖	uds_dogstatsd_to_api_v3	ingress throughput	-0.06	[-0.25, +0.13]	1	Logs
➖	quality_gate_idle	memory utilization	-0.06	[-0.11, -0.02]	1	Logs bounds checks dashboard
➖	file_to_blackhole_100ms_latency	egress throughput	-0.08	[-0.21, +0.06]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	-0.14	[-0.18, -0.10]	1	Logs bounds checks dashboard
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	-0.31	[-0.55, -0.07]	1	Logs
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	-0.32	[-0.37, -0.27]	1	Logs
➖	otlp_ingest_logs	memory utilization	-0.37	[-0.47, -0.27]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-0.53	[-0.73, -0.32]	1	Logs
➖	otlp_ingest_metrics	memory utilization	-0.56	[-0.72, -0.41]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	721 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	246.33MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	696 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.16GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.20GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.17GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.18GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	141.95MiB ≤ 147MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	471.57MiB ≤ 495MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	178.09MiB ≤ 195MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	354.24 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	3 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	380.18MiB ≤ 430MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard

Explanation

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

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

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".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.