Support additional Cluster Agent Remote Configuration clients

[clamoriniere]

What does this PR do?

Allows the Cluster Agent to run several Remote Configuration clients in one process, each with its own endpoint, API key, TUF roots and cache database.

An additional client is named after the subsystem it serves, which selects the RC products it owns — autoscaling, kubeactions, private_action_runner or apm_instrumentation:

cluster_agent:
  remote_configuration:
    additional_clients:
      autoscaling:
        rc_dd_url: https://config.datacat.com
        site: datacat.com
        api_key: ENC[k8s_secret@datadog/datadog-secret/datacat-api-key]

Products no client claims stay on the default client and the default cache, so existing deployments are unaffected. Clients are built lazily, only once a product they own is requested.

The setting is not published in the generated datadog.yaml documentation: it exists for testing the Cluster Agent against a second backend, not for customer configuration.

Motivation

The Cluster Agent assumed a single Remote Configuration client per process, which made endpoint and API key ownership process wide: every service watched the top-level api_key, status expvars were shared, and instances would have reused the same cache database.

Running autoscaling against a different Remote Configuration backend than the rest of the Cluster Agent requires those resources to be per-instance.

Describe how you validated your changes

Unit tests covering spec parsing and validation, product routing, lazy client creation, per-instance status and API key isolation.

Also validated end to end on a local kind cluster, with the autoscaling client pointed at a second Remote Configuration backend while the default client stayed on production: both clients authenticated independently, kept separate cache databases, and the autoscaling client received live configuration.

Additional Notes

Configuration that cannot work is rejected at startup rather than degrading quietly: an unknown client name, a cache filename that is not a basename or that collides with another client's, and products used by one subsystem split across two clients.

Stacked below #55619, which reports these clients in datadog-cluster-agent status.

🤖 PR description and code assisted by Claude:claude-opus-5

[github-actions]

AI review by Codex (OpenAI) - workflow run

Patch is incorrect: additional Remote Config instances are collected but omitted from human-readable status output.

[github-actions]

AI review by Codex (OpenAI) - workflow run

Patch is incorrect: the new status endpoint sanitization can still expose credentials embedded in URL query parameters or fragments.

[datadog-prod-us1-6]

An additional client starts before its subsystem adds the subscription. Cached configuration can arrive during this gap, and later unchanged polls do not send it again.

_{Open Bits AI session}

_{🤖 Datadog Autotest · Commit 1b6506f · What is Autotest? · @DataDog review to ask questions · Any feedback? Reach out in #autotest}

[datadog-prod-us1-6]

🎯 Code Coverage (details)
• Patch Coverage: 48.12%
• Overall Coverage: 52.73% (-1.15%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 9322eb4 | Docs | View more details | Give us feedback!}

[dd-octo-sts]

Files inventory check summary

File checks results against ancestor eb7754dc:

Results for datadog-agent_7.84.0~devel.git.591.9322eb4.pipeline.134080467-1_amd64.deb:

No change detected

Results for datadog-iot-agent_7.84.0~devel.git.591.9322eb4.pipeline.134080467-1_amd64.deb:

No change detected

[dd-octo-sts]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor eb7754d
📊 Static Quality Gates Dashboard
🔗 SQG Job
SOME SIZE DELTAS ARE N/A (ANCESTOR METRICS NOT YET AVAILABLE). RETRY JOB

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	N/A	N/A → 761.729 → 764.840
✅	agent_deb_amd64_fips	N/A	N/A → 713.983 → 716.080
✅	agent_heroku_amd64	N/A	N/A → 312.990 → 319.080
✅	agent_msi	N/A	N/A → 648.394 → 661.050
✅	agent_rpm_amd64	N/A	N/A → 761.713 → 764.810
✅	agent_rpm_amd64_fips	N/A	N/A → 713.966 → 716.080
✅	agent_rpm_arm64	N/A	N/A → 737.591 → 738.310
✅	agent_rpm_arm64_fips	N/A	N/A → 693.190 → 694.350
✅	agent_suse_amd64	N/A	N/A → 761.713 → 764.810
✅	agent_suse_amd64_fips	N/A	N/A → 713.966 → 716.080
✅	agent_suse_arm64	N/A	N/A → 737.591 → 738.310
✅	agent_suse_arm64_fips	N/A	N/A → 693.190 → 694.350
✅	docker_agent_amd64	N/A	N/A → 820.738 → 821.000
✅	docker_agent_arm64	N/A	N/A → 821.659 → 821.980
✅	docker_agent_jmx_amd64	N/A	N/A → 1011.650 → 1011.910
✅	docker_agent_jmx_arm64	N/A	N/A → 1001.352 → 1001.680
✅	docker_cluster_agent_amd64	N/A	N/A → 211.297 → 212.130
✅	docker_cluster_agent_arm64	N/A	N/A → 224.399 → 225.220
✅	docker_cws_instrumentation_amd64	N/A	N/A → 7.439 → 8.400
✅	docker_cws_instrumentation_arm64	N/A	N/A → 6.877 → 7.110
✅	docker_dogstatsd_amd64	N/A	N/A → 39.553 → 40.440
✅	docker_dogstatsd_arm64	N/A	N/A → 37.623 → 38.580
✅	docker_host_profiler_amd64	N/A	N/A → 306.870 → 317.700
✅	docker_host_profiler_arm64	N/A	N/A → 318.168 → 328.970
✅	dogstatsd_deb_amd64	N/A	N/A → 30.290 → 31.210
✅	dogstatsd_deb_arm64	N/A	N/A → 28.306 → 29.590
✅	dogstatsd_rpm_amd64	N/A	N/A → 30.290 → 31.210
✅	dogstatsd_suse_amd64	N/A	N/A → 30.290 → 31.210
✅	iot_agent_deb_amd64	N/A	N/A → 46.576 → 47.550
✅	iot_agent_deb_arm64	N/A	N/A → 43.212 → 44.220
✅	iot_agent_deb_armhf	N/A	N/A → 44.018 → 45.020
✅	iot_agent_rpm_amd64	N/A	N/A → 46.576 → 47.550
✅	iot_agent_suse_amd64	N/A	N/A → 46.575 → 47.550

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Job ID: 76df128c-9f0b-43c8-867d-8512489d51fd

Baseline: eb7754d
Comparison: 9322eb4
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	quality_gate_logs	% cpu utilization	+0.95	[+0.07, +1.84]	1	Logs bounds checks dashboard
➖	quality_gate_security_idle	memory utilization	+0.55	[+0.51, +0.60]	1	Logs bounds checks dashboard
➖	quality_gate_private_action_runner	memory utilization	+0.37	[+0.25, +0.49]	1	Logs bounds checks dashboard
➖	quality_gate_security_no_fs_load	memory utilization	+0.33	[+0.25, +0.40]	1	Logs bounds checks dashboard
➖	dsd_uds_10mb_3k_timestamped_contexts_cpu	% cpu utilization	+0.18	[-0.06, +0.42]	1	Logs
➖	dsd_uds_10mb_3k_timestamped_contexts_memory	memory utilization	+0.17	[-0.05, +0.38]	1	Logs
➖	quality_gate_idle	memory utilization	+0.10	[+0.06, +0.14]	1	Logs bounds checks dashboard
➖	quality_gate_idle_all_features	memory utilization	-0.19	[-0.23, -0.15]	1	Logs bounds checks dashboard
➖	quality_gate_security_mean_fs_load	memory utilization	-0.24	[-0.28, -0.21]	1	Logs bounds checks dashboard
➖	quality_gate_metrics_logs	memory utilization	-0.93	[-1.16, -0.70]	1	Logs bounds checks dashboard

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	quality_gate_idle	intake_connections	10/10	4 = 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	172.80MiB ≤ 179MiB	bounds checks dashboard
✅	quality_gate_idle	total_bytes_received	10/10	746.69KiB ≤ 819.20KiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	4 = 4	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	515.71MiB ≤ 537MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	total_bytes_received	10/10	1.14MiB ≤ 1.25MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	18 ≤ 40	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	210.56MiB ≤ 220MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_logs	total_bytes_received	10/10	263.42MiB ≤ 292MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	365.68 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	19 ≤ 40	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	433.92MiB ≤ 455MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	total_bytes_received	10/10	0.94GiB ≤ 1.04GiB	bounds checks dashboard
✅	quality_gate_private_action_runner	memory_usage	10/10	72.23MiB ≤ 75MiB	bounds checks dashboard
✅	quality_gate_security_idle	cpu_usage	10/10	28.32 ≤ 100	bounds checks dashboard
✅	quality_gate_security_idle	memory_usage	10/10	325.19MiB ≤ 355MiB	bounds checks dashboard
✅	quality_gate_security_mean_fs_load	cpu_usage	10/10	60.48 ≤ 200	bounds checks dashboard
✅	quality_gate_security_mean_fs_load	memory_usage	10/10	306.06MiB ≤ 335MiB	bounds checks dashboard
✅	quality_gate_security_no_fs_load	cpu_usage	10/10	21.43 ≤ 100	bounds checks dashboard
✅	quality_gate_security_no_fs_load	memory_usage	10/10	313.17MiB ≤ 345MiB	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_private_action_runner, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_mean_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_mean_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_idle, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_idle, bounds check memory_usage: 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.
• quality_gate_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_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_metrics_logs, bounds check total_bytes_received: 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 memory_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_idle, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_security_no_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_no_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.