fix(aggregator): honor forceFlushAll on MicroVM's on-demand Flush

[litianningdatadog]

Driven by Codex's comment on #54111: #54111 (comment)

/suspend and /terminate call Flush() to make MicroVM telemetry durable before the VM is snapshotted or torn down. ForceFlushToSerializer ignored that intent and always skipped the current, still-open time bucket — a metric emitted right before the call, including the /terminate metric itself, could get dropped with nothing to retry once the VM is gone. That lines up with aws.lambda.enhanced.microvm.terminate having zero data points anywhere in the org for the last 30 days.

This threads a real forceFlushAll flag from MicroVM down through ServerlessMetricAgent.Flush() into Demultiplexer.ForceFlushToSerializer. Every other cloud service opts out — none of them call Flush() outside the normal periodic/shutdown cycle, so nothing else changes.

The other issue from that comment — SampleDrainer never being wired up — needs new drain plumbing in pkg/aggregator's timeSamplerWorker; the existing shutdown()/waitForShutdown() is one-shot and would panic on a second /suspend. That's a separate PR.

Test plan

• New tests prove the fix directly: a sample in the current open bucket is delivered when forceFlushAll is true, never delivered when false.
• dda inv test on every touched package (pkg/aggregator, pkg/serverless, cmd/serverless-init, pkg/clusteragent/.../kubernetesadmissionevents) — all green.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

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[Copilot]

Pull request overview

This PR ensures AWS Lambda MicroVM lifecycle-triggered metric flushes (/suspend, /terminate) can include samples still in the current (not-yet-closed) DogStatsD time bucket, preventing “last-moment” telemetry (including the terminate metric itself) from being dropped with no chance to retry after the VM is gone.

Changes:

• Extend aggregator.Demultiplexer.ForceFlushToSerializer with a forceFlushAll flag and thread it through AgentDemultiplexer.
• Add a forceFlushAllOnFlush option to pkg/serverless/metrics.ServerlessMetricAgent and plumb it from serverless-init via a new CloudService.ShouldForceFlushAllOnForceFlushToSerializer() hook (true only for MicroVM).
• Update and add unit tests to cover open-bucket flush behavior and adjust existing call sites for the new API.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pkg/serverless/metrics/metric.go	Add forceFlushAllOnFlush to control whether Flush() includes the current open bucket.
pkg/serverless/metrics/metric_test.go	Add tests for open-bucket flushing behavior (with/without forceFlushAll).
pkg/clusteragent/admission/validate/kubernetesadmissionevents/kubernetesadmissionevents_test.go	Update mock demux flush call for the new ForceFlushToSerializer signature.
pkg/aggregator/demultiplexer.go	Update Demultiplexer interface to accept forceFlushAll.
pkg/aggregator/demultiplexer_agent.go	Thread forceFlushAll into the trigger path for manual flushes.
pkg/aggregator/demultiplexer_agent_test.go	Update tests for new ForceFlushToSerializer signature.
pkg/aggregator/aggregator_test.go	Update tests for new ForceFlushToSerializer signature.
cmd/serverless-init/main.go	Pass per-cloud-service forceFlushAll intent into the metric agent.
cmd/serverless-init/main_test.go	Update metric agent construction for new signature.
cmd/serverless-init/lifecycle/server.go	Comment update to reflect lambda_microvm_id tag naming.
cmd/serverless-init/lifecycle/server_test.go	Update assertions to match lambda_microvm_id tag naming.
cmd/serverless-init/lifecycle/heartbeat.go	Emit lambda_microvm_id:<id> tag instead of microvm_id:<id>.
cmd/serverless-init/lifecycle/heartbeat_test.go	Update tests to expect lambda_microvm_id tagging.
cmd/serverless-init/cloudservice/service.go	Extend CloudService interface with ShouldForceFlushAllOnForceFlushToSerializer.
cmd/serverless-init/cloudservice/service_test.go	Add test pinning MicroVM as the only service returning true.
cmd/serverless-init/cloudservice/microvm.go	Return true for MicroVM to force-flush open buckets on lifecycle flushes.
cmd/serverless-init/cloudservice/containerapp.go	Implement new CloudService method (returns false).
cmd/serverless-init/cloudservice/cloudrun.go	Implement new CloudService method (returns false).
cmd/serverless-init/cloudservice/cloudrun_jobs.go	Implement new CloudService method (returns false).
cmd/serverless-init/cloudservice/appservice.go	Implement new CloudService method (returns false).

Comments suppressed due to low confidence (1)

pkg/serverless/metrics/metric_test.go:300

• Same determinism concern as the positive control: using time.Now() for the sample timestamp means this negative-control test can intermittently flush the sample if a bucket boundary is crossed during the loop, even though the intent is to keep the sample in an always-open bucket. Using a future timestamp makes the test stable and ensures it actually validates open-bucket skipping behavior.

	now := float64(time.Now().UnixNano()) / float64(time.Second)
	agent.AddEnhancedMetric("test.metric", 1.0, pkgmetrics.MetricSourceServerless, now)

---

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[datadog-datadog-prod-us1]

🎯 Code Coverage (details)
• Patch Coverage: 85.71%
• Overall Coverage: 52.16% (+0.00%)

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🔗 Commit SHA: d98a128 | Docs | Datadog PR Page | Give us feedback!}

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

[dd-octo-sts]

Files inventory check summary

File checks results against ancestor 8d8cc340:

Results for datadog-agent_7.83.0~devel.git.375.d98a128.pipeline.126931455-1_amd64.deb:

No change detected

[dd-octo-sts]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor 8d8cc34
📊 Static Quality Gates Dashboard
🔗 SQG Job

Successful checks

Info

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64_fips	+5.96 KiB (0.00% increase, -0.13% of buffer)	706.062 → 706.068 → 710.520
✅	agent_rpm_amd64_fips	+5.96 KiB (0.00% increase, -0.13% of buffer)	706.046 → 706.052 → 710.520
✅	agent_rpm_arm64	+4.57 KiB (0.00% increase, -0.26% of buffer)	727.928 → 727.932 → 729.660
✅	agent_suse_amd64_fips	+5.96 KiB (0.00% increase, -0.13% of buffer)	706.046 → 706.052 → 710.520
✅	agent_suse_arm64	+4.57 KiB (0.00% increase, -0.26% of buffer)	727.928 → 727.932 → 729.660
✅	docker_agent_amd64	+8.55 KiB (0.00% increase, -0.22% of buffer)	809.955 → 809.963 → 813.790
✅	docker_agent_arm64	+11.17 KiB (0.00% increase, -0.32% of buffer)	811.656 → 811.667 → 815.030
✅	docker_agent_jmx_amd64	+8.56 KiB (0.00% increase, -0.23% of buffer)	1000.852 → 1000.860 → 1004.550
✅	docker_agent_jmx_arm64	+11.17 KiB (0.00% increase, -0.31% of buffer)	991.206 → 991.217 → 994.710
✅	docker_cluster_agent_arm64	-63.85 KiB (0.03% reduction, +226.96% of buffer)	222.953 → 222.890 → 222.980
✅	docker_host_profiler_amd64	+13.03 KiB (0.00% increase, -0.09% of buffer)	303.876 → 303.888 → 317.640
✅	docker_host_profiler_arm64	+13.05 KiB (0.00% increase, -0.09% of buffer)	315.371 → 315.383 → 328.900

21 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64	751.292 MiB
✅	agent_heroku_amd64	307.539 MiB
✅	agent_msi	639.501 MiB
✅	agent_rpm_amd64	751.275 MiB
✅	agent_rpm_arm64_fips	685.851 MiB
✅	agent_suse_amd64	751.275 MiB
✅	agent_suse_arm64_fips	685.851 MiB
✅	docker_cluster_agent_amd64	209.866 MiB
✅	docker_cws_instrumentation_amd64	7.439 MiB
✅	docker_cws_instrumentation_arm64	6.877 MiB
✅	docker_dogstatsd_amd64	39.243 MiB
✅	docker_dogstatsd_arm64	37.368 MiB
✅	dogstatsd_deb_amd64	29.984 MiB
✅	dogstatsd_deb_arm64	28.024 MiB
✅	dogstatsd_rpm_amd64	29.984 MiB
✅	dogstatsd_suse_amd64	29.984 MiB
✅	iot_agent_deb_amd64	46.153 MiB
✅	iot_agent_deb_arm64	42.845 MiB
✅	iot_agent_deb_armhf	43.613 MiB
✅	iot_agent_rpm_amd64	46.154 MiB
✅	iot_agent_suse_amd64	46.153 MiB

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 02238e4e-f28d-4b16-8847-3a05adde50dc

Baseline: 8d8cc34
Comparison: d98a128
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_private_action_runner	memory utilization	+0.73	[+0.61, +0.85]	1	Logs bounds checks dashboard
➖	quality_gate_security_no_fs_load	memory utilization	+0.29	[+0.20, +0.38]	1	Logs bounds checks dashboard
➖	quality_gate_idle	memory utilization	+0.18	[+0.12, +0.23]	1	Logs bounds checks dashboard
➖	quality_gate_security_mean_fs_load	memory utilization	-0.10	[-0.14, -0.06]	1	Logs bounds checks dashboard
➖	quality_gate_security_idle	memory utilization	-0.20	[-0.26, -0.14]	1	Logs bounds checks dashboard
➖	quality_gate_idle_all_features	memory utilization	-0.22	[-0.27, -0.18]	1	Logs bounds checks dashboard
➖	quality_gate_metrics_logs	memory utilization	-0.55	[-0.80, -0.30]	1	Logs bounds checks dashboard
➖	quality_gate_logs	% cpu utilization	-0.84	[-1.85, +0.16]	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	3 ≤ 4	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	148.01MiB ≤ 154MiB	bounds checks dashboard
✅	quality_gate_idle	total_bytes_received	10/10	735.47KiB ≤ 819.20KiB	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	498.43MiB ≤ 512MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	total_bytes_received	10/10	1.13MiB ≤ 1.25MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	3 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	182.95MiB ≤ 195MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_logs	total_bytes_received	10/10	263.77MiB ≤ 292MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	363.09 ≤ 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	401.56MiB ≤ 430MiB	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	71.41MiB ≤ 75MiB	bounds checks dashboard
✅	quality_gate_security_idle	cpu_usage	10/10	30.99 ≤ 100	bounds checks dashboard
✅	quality_gate_security_idle	memory_usage	10/10	301.63MiB ≤ 330MiB	bounds checks dashboard
✅	quality_gate_security_mean_fs_load	cpu_usage	10/10	83.80 ≤ 200	bounds checks dashboard
✅	quality_gate_security_mean_fs_load	memory_usage	10/10	277.98MiB ≤ 310MiB	bounds checks dashboard
✅	quality_gate_security_no_fs_load	cpu_usage	10/10	25.26 ≤ 100	bounds checks dashboard
✅	quality_gate_security_no_fs_load	memory_usage	10/10	288.87MiB ≤ 320MiB	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".

Replicate Execution Details

We run multiple replicates for each experiment/variant. However, we allow replicates to be automatically retried if there are any failures, up to 8 times, at which point the replicate is marked dead and we are unable to run analysis for the entire experiment. We call each of these attempts at running replicates a replicate execution. This section lists all replicate executions that failed due to the target crashing or being oom killed.

Note: In the below tables we bucket failures by experiment, variant, and failure type. For each of these buckets we list out the replicate indexes that failed with an annotation signifying how many times said replicate failed with the given failure mode. In the below example the baseline variant of the experiment named experiment_with_failures had two replicates that failed by oom kills. Replicate 0, which failed 8 executions, and replicate 1 which failed 6 executions, all with the same failure mode.

Experiment	Variant	Replicates	Failure	Logs	Debug Dashboard
experiment_with_failures	baseline	0 (x8) 1 (x6)	Oom killed		Debug Dashboard

The debug dashboard links will take you to a debugging dashboard specifically designed to investigate replicate execution failures.

❌ Retried Profiling Replicate Execution Failures (ddprof)

Note: Profiling replicas may still be executing. See the debug dashboard for up to date status.

Experiment	Variant	Replicates	Failure	Debug Dashboard
quality_gate_idle_all_features	baseline	10	Oom killed	Debug Dashboard
quality_gate_idle_all_features	comparison	10	Oom killed	Debug Dashboard
quality_gate_logs	baseline	10	Oom killed	Debug Dashboard
quality_gate_logs	comparison	10	Oom killed	Debug Dashboard
quality_gate_metrics_logs	baseline	10	Oom killed	Debug Dashboard
quality_gate_metrics_logs	comparison	10	Oom killed	Debug Dashboard
quality_gate_security_idle	comparison	10	Oom killed	Debug Dashboard
quality_gate_security_no_fs_load	baseline	10	Crashed (exit code: 134)	Debug Dashboard
quality_gate_security_no_fs_load	comparison	10	Crashed (exit code: 134)	Debug Dashboard

CI Pass/Fail Decision

✅ Passed. All Quality Gates 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_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.
• 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 cpu_usage: 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 total_bytes_received: 10/10 replicas passed. Gate passed.
• quality_gate_private_action_runner, 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_mean_fs_load, bounds check memory_usage: 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_security_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_security_idle, bounds check cpu_usage: 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 missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.