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fix empty linux kernel platform information #22139

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merged 1 commit into from
Jan 19, 2024

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What does this PR do?

Uses github.com/DataDog/gopsutil instead of github.com/shirou/gopsutil/v3 for getting kernel platform information.

Motivation

If github.com/shirou/gopsutil/v3 is used and a [/host]/etc/redhat-release file/dir exists but is empty, then it returns empty platform information.

This affects helm-chart users who have kernel header downloading turned on, because it always mounts this file and k8s will create it even if it doesn't exist.

Additional Notes

This is because this line https://github.com/shirou/gopsutil/blob/83c941c791e7f294752b0cc98ba3059f63dd4f05/host/host_linux.go#L238 does not use common.PathExistsWithContents.

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

Reviewer's Checklist

  • If known, an appropriate milestone has been selected; otherwise the Triage milestone is set.
  • Use the major_change label if your change either has a major impact on the code base, is impacting multiple teams or is changing important well-established internals of the Agent. This label will be use during QA to make sure each team pay extra attention to the changed behavior. For any customer facing change use a releasenote.
  • A release note has been added or the changelog/no-changelog label has been applied.
  • Changed code has automated tests for its functionality.
  • Adequate QA/testing plan information is provided. Except if the qa/skip-qa label, with required either qa/done or qa/no-code-change labels, are applied.
  • At least one team/.. label has been applied, indicating the team(s) that should QA this change.
  • If applicable, docs team has been notified or an issue has been opened on the documentation repo.
  • If applicable, the need-change/operator and need-change/helm labels have been applied.
  • If applicable, the k8s/<min-version> label, indicating the lowest Kubernetes version compatible with this feature.
  • If applicable, the config template has been updated.

@brycekahle brycekahle added changelog/no-changelog [deprecated] qa/skip-qa - use other qa/ labels [DEPRECATED] Please use qa/done or qa/no-code-change to skip creating a QA card team/ebpf-platform qa/done QA done before merge and regressions are covered by tests labels Jan 17, 2024
@brycekahle brycekahle added this to the 7.52.0 milestone Jan 17, 2024
@brycekahle brycekahle requested a review from a team as a code owner January 17, 2024 22:47
If github.com/shirou/gopsutil/v3 is used and a [/host]/etc/redhat-release file/dir exists but is empty, then it returns empty platform information.

This affects helm-chart users who have kernel header downloading turned on, because it always mounts this file and k8s will create it even if it doesn't exist.
@brycekahle brycekahle force-pushed the bryce.kahle/fix-platform-empty branch from 9c47a0f to fc0b024 Compare January 17, 2024 22:50
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pr-commenter bot commented Jan 18, 2024

Bloop Bleep... Dogbot Here

Regression Detector Results

Run ID: 98f716d5-ee8c-4e43-ab3a-ec80f046b2d9
Baseline: 8dba779
Comparison: fc0b024
Total CPUs: 7

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.

Experiments ignored for regressions

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

perf experiment goal Δ mean % Δ mean % CI
idle memory utilization +0.31 [+0.27, +0.35]
file_tree memory utilization +0.27 [+0.13, +0.40]
file_to_blackhole % cpu utilization -0.62 [-7.14, +5.90]

Fine details of change detection per experiment

perf experiment goal Δ mean % Δ mean % CI
uds_dogstatsd_to_api_cpu % cpu utilization +0.65 [-0.78, +2.07]
process_agent_standard_check_with_stats memory utilization +0.52 [+0.45, +0.59]
process_agent_real_time_mode memory utilization +0.38 [+0.34, +0.42]
idle memory utilization +0.31 [+0.27, +0.35]
file_tree memory utilization +0.27 [+0.13, +0.40]
process_agent_standard_check memory utilization +0.08 [+0.00, +0.15]
tcp_dd_logs_filter_exclude ingress throughput -0.00 [-0.06, +0.06]
uds_dogstatsd_to_api ingress throughput -0.00 [-0.03, +0.03]
trace_agent_json ingress throughput -0.07 [-0.10, -0.05]
trace_agent_msgpack ingress throughput -0.10 [-0.12, -0.08]
tcp_syslog_to_blackhole ingress throughput -0.29 [-0.35, -0.22]
file_to_blackhole % cpu utilization -0.62 [-7.14, +5.90]
otel_to_otel_logs ingress throughput -1.11 [-1.80, -0.41]

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".

@@ -8,7 +8,7 @@
package kernel

import (
gopsutilhost "github.com/shirou/gopsutil/v3/host"
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going back to our completely unmaintained fork feels like a mistake, what are we losing to fix the issue you found ? I would like to see an upstream PR fixing the issue so that we can go back to upstream ASAP

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Opened an upstream PR to fix this particular issue: shirou/gopsutil#1584

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We will need this change too, which might be more controversial: https://github.com/DataDog/gopsutil/pull/44/files

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@brycekahle
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/merge

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dd-devflow bot commented Jan 19, 2024

🚂 MergeQueue

Pull request added to the queue.

This build is going to start soon! (estimated merge in less than 46m)

Use /merge -c to cancel this operation.!

@dd-mergequeue dd-mergequeue bot merged commit caa29ec into main Jan 19, 2024
204 checks passed
@dd-mergequeue dd-mergequeue bot deleted the bryce.kahle/fix-platform-empty branch January 19, 2024 21:51
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3 participants