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Add 'preserve_root_device' config flag and mountinfo parser for raw device names #37878

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What does this PR do?

This PR introduces a new boolean configuration flag, preserve_root_device (default true), which lets users opt-in to seeing the original mount sources (e.g. /dev/root) exactly as they appear in /proc/self/mountinfo. When set to false, we fall back to gopsutil’s resolved device paths (e.g. /dev/nvme0n1p2).

Motivation

When migrating our disk checks from Python’s psutil to Go’s gopsutil, we discovered that by default:

  • Raw sources get “resolved”: gopsutil never reports /dev/root or overlay—it always looks up the underlying block device (e.g. /dev/nvme0n1p2) by reading /proc/1/mountinfo (falling back to /proc/self/mountinfo).
  • Context is lost in containers/overlays: in Docker, Kubernetes or other overlay fs setups, users expect to see the literal mount source (/dev/root, overlay) as shown in /proc/self/mountinfo, not the host’s NVMe device.

These differences led to inconsistent results inside containers (see here). By adding this new flag and mountinfo parser, we preserve the original mount source names by default, restoring parity with psutil, while still allowing fully-resolved host paths when desired setting preserve_root_device to false

Describe how you validated your changes

Possible Drawbacks / Trade-offs

Additional Notes

@jose-manuel-almaza jose-manuel-almaza requested review from a team as code owners June 12, 2025 07:55
@github-actions github-actions bot added short review PR is simple enough to be reviewed quickly team/agent-runtimes labels Jun 12, 2025
@jose-manuel-almaza jose-manuel-almaza added changelog/no-changelog qa/done QA done before merge and regressions are covered by tests labels Jun 12, 2025
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cit-pr-commenter bot commented Jun 12, 2025 •
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Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: e1ca397f-9b76-4a58-9fa5-cb7d1e045cbe

Baseline: 641d806
Comparison: 007c1c5
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf experiment goal Δ mean % Δ mean % CI trials links
➖ docker_containers_cpu % cpu utilization +2.92 [-0.06, +5.90] 1 Logs
➖ uds_dogstatsd_to_api_cpu % cpu utilization +1.27 [+0.41, +2.13] 1 Logs
➖ ddot_logs memory utilization +0.56 [+0.44, +0.67] 1 Logs
➖ quality_gate_logs % cpu utilization +0.51 [-2.26, +3.28] 1 Logs bounds checks dashboard
➖ quality_gate_idle memory utilization +0.29 [+0.20, +0.37] 1 Logs bounds checks dashboard
➖ file_to_blackhole_0ms_latency_http1 egress throughput +0.11 [-0.49, +0.71] 1 Logs
➖ file_to_blackhole_500ms_latency egress throughput +0.10 [-0.53, +0.73] 1 Logs
➖ docker_containers_memory memory utilization +0.09 [+0.03, +0.15] 1 Logs
➖ file_to_blackhole_100ms_latency egress throughput +0.03 [-0.57, +0.63] 1 Logs
➖ file_to_blackhole_1000ms_latency egress throughput +0.02 [-0.57, +0.62] 1 Logs
➖ otlp_ingest_logs memory utilization +0.02 [-0.11, +0.15] 1 Logs
➖ file_tree memory utilization +0.01 [-0.13, +0.15] 1 Logs
➖ file_to_blackhole_300ms_latency egress throughput +0.01 [-0.56, +0.58] 1 Logs
➖ uds_dogstatsd_to_api ingress throughput +0.00 [-0.28, +0.28] 1 Logs
➖ tcp_dd_logs_filter_exclude ingress throughput +0.00 [-0.02, +0.02] 1 Logs
➖ file_to_blackhole_0ms_latency_http2 egress throughput -0.00 [-0.59, +0.59] 1 Logs
➖ file_to_blackhole_1000ms_latency_linear_load egress throughput -0.01 [-0.24, +0.23] 1 Logs
➖ file_to_blackhole_0ms_latency egress throughput -0.05 [-0.61, +0.50] 1 Logs
➖ uds_dogstatsd_20mb_12k_contexts_20_senders memory utilization -0.12 [-0.16, -0.07] 1 Logs
➖ otlp_ingest_metrics memory utilization -0.17 [-0.33, -0.00] 1 Logs
➖ ddot_metrics memory utilization -0.47 [-0.59, -0.35] 1 Logs
➖ quality_gate_idle_all_features memory utilization -0.49 [-0.57, -0.41] 1 Logs bounds checks dashboard
➖ tcp_syslog_to_blackhole ingress throughput -1.32 [-1.37, -1.27] 1 Logs

Bounds Checks: ✅ Passed

perf experiment bounds_check_name replicates_passed links
✅ docker_containers_cpu simple_check_run 10/10
✅ docker_containers_memory memory_usage 10/10
✅ docker_containers_memory simple_check_run 10/10
✅ file_to_blackhole_0ms_latency lost_bytes 10/10
✅ file_to_blackhole_0ms_latency memory_usage 10/10
✅ file_to_blackhole_0ms_latency_http1 lost_bytes 10/10
✅ file_to_blackhole_0ms_latency_http1 memory_usage 10/10
✅ file_to_blackhole_0ms_latency_http2 lost_bytes 10/10
✅ file_to_blackhole_0ms_latency_http2 memory_usage 10/10
✅ file_to_blackhole_1000ms_latency memory_usage 10/10
✅ file_to_blackhole_1000ms_latency_linear_load memory_usage 10/10
✅ file_to_blackhole_100ms_latency lost_bytes 10/10
✅ file_to_blackhole_100ms_latency memory_usage 10/10
✅ file_to_blackhole_300ms_latency lost_bytes 10/10
✅ file_to_blackhole_300ms_latency memory_usage 10/10
✅ file_to_blackhole_500ms_latency lost_bytes 10/10
✅ file_to_blackhole_500ms_latency memory_usage 10/10
✅ quality_gate_idle intake_connections 10/10 bounds checks dashboard
✅ quality_gate_idle memory_usage 10/10 bounds checks dashboard
✅ quality_gate_idle_all_features intake_connections 10/10 bounds checks dashboard
✅ quality_gate_idle_all_features memory_usage 10/10 bounds checks dashboard
✅ quality_gate_logs intake_connections 10/10 bounds checks dashboard
✅ quality_gate_logs lost_bytes 10/10 bounds checks dashboard
✅ quality_gate_logs memory_usage 10/10 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, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate 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_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 lost_bytes: 10/10 replicas passed. Gate passed.

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agent-platform-auto-pr bot commented Jun 12, 2025 •
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Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor 641d806

Successful checks

Info

Quality gate Delta On disk size (MiB) Delta On wire size (MiB)
✅ agent_deb_amd64 $${+0.01}$$ $${696.38}$$ < $${697.37}$$ $${-0.01}$$ $${176.06}$$ < $${177.03}$$
✅ agent_deb_amd64_fips $${+0.02}$$ $${694.68}$$ < $${695.59}$$ $${+0.01}$$ $${175.51}$$ < $${176.51}$$
✅ agent_heroku_amd64 $${+0.01}$$ $${358.67}$$ < $${359.67}$$ $${+0}$$ $${96.52}$$ < $${97.47}$$
✅ agent_msi $${+0}$$ $${958.86}$$ < $${959.86}$$ $${0}$$ $${146.29}$$ < $${147.27}$$
✅ agent_rpm_amd64 $${+0.01}$$ $${696.37}$$ < $${697.36}$$ $${-0.05}$$ $${177.57}$$ < $${178.56}$$
✅ agent_rpm_amd64_fips $${+0.02}$$ $${694.67}$$ < $${695.58}$$ $${+0.02}$$ $${177.48}$$ < $${178.43}$$
✅ agent_rpm_arm64 $${+0.01}$$ $${686.38}$$ < $${687.37}$$ $${+0.03}$$ $${161.05}$$ < $${161.99}$$
✅ agent_rpm_arm64_fips $${+0.01}$$ $${684.8}$$ < $${685.72}$$ $${-0.03}$$ $${160.19}$$ < $${161.11}$$
✅ agent_suse_amd64 $${+0.01}$$ $${696.37}$$ < $${697.36}$$ $${-0.05}$$ $${177.57}$$ < $${178.56}$$
✅ agent_suse_amd64_fips $${+0.02}$$ $${694.67}$$ < $${695.58}$$ $${+0.02}$$ $${177.48}$$ < $${178.43}$$
✅ agent_suse_arm64 $${+0.01}$$ $${686.38}$$ < $${687.37}$$ $${+0.03}$$ $${161.05}$$ < $${161.99}$$
✅ agent_suse_arm64_fips $${+0.01}$$ $${684.8}$$ < $${685.72}$$ $${-0.03}$$ $${160.19}$$ < $${161.11}$$
✅ docker_agent_amd64 $${+0.01}$$ $${780.17}$$ < $${781.16}$$ $${+0.01}$$ $${268.69}$$ < $${269.63}$$
✅ docker_agent_arm64 $${+0.01}$$ $${793.63}$$ < $${794.62}$$ $${+0.01}$$ $${256.05}$$ < $${257.0}$$
✅ docker_agent_jmx_amd64 $${+0.01}$$ $${971.36}$$ < $${972.35}$$ $${-0.03}$$ $${337.63}$$ < $${338.6}$$
✅ docker_agent_jmx_arm64 $${+0.01}$$ $${973.42}$$ < $${974.41}$$ $${+0.02}$$ $${321.01}$$ < $${321.97}$$
✅ docker_agent_windows1809 $${+0}$$ $${1487.0}$$ < $${1488.0}$$ $${-0.11}$$ $${487.99}$$ < $${488.95}$$
✅ docker_agent_windows1809_core $${-0.24}$$ $${6216.72}$$ < $${6218.0}$$ $${0}$$ $${2048.0}$$ < $${2049.0}$$
✅ docker_agent_windows1809_core_jmx $${-0.13}$$ $${6338.53}$$ < $${6339.0}$$ $${0}$$ $${2048.0}$$ < $${2049.0}$$
✅ docker_agent_windows1809_jmx $${+0}$$ $${1608.63}$$ < $${1609.5}$$ $${-0.02}$$ $${530.35}$$ < $${531.32}$$
✅ docker_agent_windows2022 $${+0}$$ $${1506.3}$$ < $${1507.0}$$ $${+0.02}$$ $${500.78}$$ < $${501.7}$$
✅ docker_agent_windows2022_core $${+0.24}$$ $${6190.24}$$ < $${6311.0}$$ $${0}$$ $${2048.0}$$ < $${2049.0}$$
✅ docker_agent_windows2022_core_jmx $${-0.09}$$ $${6311.88}$$ < $${6313.0}$$ $${0}$$ $${2048.0}$$ < $${2049.0}$$
✅ docker_agent_windows2022_jmx $${-0.19}$$ $${1627.88}$$ < $${1628.16}$$ $${+0}$$ $${543.05}$$ < $${543.98}$$
✅ docker_cluster_agent_amd64 $${+0.01}$$ $${212.85}$$ < $${213.79}$$ $${+0}$$ $${72.38}$$ < $${73.33}$$
✅ docker_cluster_agent_arm64 $${0}$$ $${228.68}$$ < $${229.64}$$ $${-0}$$ $${68.64}$$ < $${69.6}$$
✅ docker_cws_instrumentation_amd64 $${0}$$ $${7.08}$$ < $${7.12}$$ $${+0}$$ $${2.95}$$ < $${3.29}$$
✅ docker_cws_instrumentation_arm64 $${+0}$$ $${6.69}$$ < $${6.92}$$ $${+0}$$ $${2.7}$$ < $${3.07}$$
✅ docker_dogstatsd_amd64 $${0}$$ $${39.22}$$ < $${39.57}$$ $${+0}$$ $${15.12}$$ < $${15.76}$$
✅ docker_dogstatsd_arm64 $${0}$$ $${37.88}$$ < $${38.2}$$ $${+0}$$ $${14.53}$$ < $${14.83}$$
✅ dogstatsd_deb_amd64 $${0}$$ $${30.45}$$ < $${31.4}$$ $${-0}$$ $${8.0}$$ < $${8.95}$$
✅ dogstatsd_deb_arm64 $${0}$$ $${29.02}$$ < $${29.97}$$ $${+0}$$ $${6.94}$$ < $${7.89}$$
✅ dogstatsd_rpm_amd64 $${0}$$ $${30.45}$$ < $${31.4}$$ $${-0}$$ $${8.01}$$ < $${8.96}$$
✅ dogstatsd_suse_amd64 $${0}$$ $${30.45}$$ < $${31.4}$$ $${-0}$$ $${8.01}$$ < $${8.96}$$
✅ iot_agent_deb_amd64 $${+0.02}$$ $${50.44}$$ < $${51.38}$$ $${+0.01}$$ $${12.84}$$ < $${13.79}$$
✅ iot_agent_deb_arm64 $${+0.01}$$ $${47.91}$$ < $${48.85}$$ $${+0}$$ $${11.14}$$ < $${12.09}$$
✅ iot_agent_deb_armhf $${+0.01}$$ $${47.48}$$ < $${48.42}$$ $${+0.01}$$ $${11.2}$$ < $${12.16}$$
✅ iot_agent_rpm_amd64 $${+0.02}$$ $${50.44}$$ < $${51.38}$$ $${+0.01}$$ $${12.86}$$ < $${13.81}$$
✅ iot_agent_rpm_arm64 $${+0.01}$$ $${47.91}$$ < $${48.85}$$ $${+0.01}$$ $${11.16}$$ < $${12.11}$$
✅ iot_agent_suse_amd64 $${+0.02}$$ $${50.44}$$ < $${51.38}$$ $${+0.01}$$ $${12.86}$$ < $${13.81}$$

@github-actions github-actions bot added medium review PR review might take time and removed short review PR is simple enough to be reviewed quickly labels Jun 13, 2025
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clarkb7 approved these changes Jun 13, 2025
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looks like issue may not be applicable to Windows
same value used for mountpoint and device in both gopsutil and python psutil

https://github.com/shirou/gopsutil/blob/ad10d4d2575ddf908388cf0c4005a07bcea8d812/disk/disk_windows.go#L151-L156

https://github.com/giampaolo/psutil/blob/3d21a43a47ab6f3c4a08d235d2a9a55d4adae9b1/psutil/arch/windows/disk.c#L325-L326

@jose-manuel-almaza jose-manuel-almaza requested a review from a team as a code owner June 16, 2025 05:37
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