usm: Enable event monitoring if USM is enabled and loaded

[guyarb]

What does this PR do?

Fixing a possible panic in the code base and a bug in which the USM event monitor can run without USM.

The fix is to enable USM's event monitoring if the appropriate configuration is set (like today) but also to check USM is enabled (to prevent a case in which USM is disabled, event monitoring is enabled, and we execute redundant code). Also, we initialize USM event monitor only if the network tracer successfully started

Motivation

If USM was enabled with event monitoring, but NPM failed to start (for instance, conntracker failure) the network tracer component didn't start, but the event monitoring of USM would start, and once we got an event of a process execution or termination, we would try to update our telemetry object which was never initialized, causing a panic as some fields are pointers (nil pointers).

The bug revealed both a possible panic in the code, but also the fact that event monitoring of USM can run even if USM failed to start.

Additional Notes

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

[pr-commenter]

Test changes on VM

Use this command from test-infra-definitions to manually test this PR changes on a VM:

inv create-vm --pipeline-id=42589299 --os-family=ubuntu

Note: This applies to commit 5421485

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: d8918ca7-e88e-42e7-9b8b-01be889b9e2f Metrics dashboard Target profiles

Baseline: 107b2fc
Comparison: 5421485

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.

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	links
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+0.57	[-0.23, +1.36]	Logs
➖	otel_to_otel_logs	ingress throughput	+0.24	[-0.57, +1.05]	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.01, +0.01]	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.01	[-0.07, +0.05]	Logs
➖	idle	memory utilization	-0.44	[-0.49, -0.40]	Logs
➖	file_tree	memory utilization	-0.50	[-0.58, -0.42]	Logs
➖	pycheck_lots_of_tags	% cpu utilization	-0.87	[-3.30, +1.56]	Logs
➖	basic_py_check	% cpu utilization	-1.31	[-4.07, +1.45]	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-5.86	[-18.36, +6.63]	Logs

Bounds Checks

perf	experiment	bounds_check_name	replicates_passed
✅	idle	memory_usage	10/10

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".

[guyarb]

/merge

[dd-devflow]

🚂 MergeQueue: pull request added to the queue

The median merge time in main is 22m.

Use /merge -c to cancel this operation!