[USM] Handle Istio binary path

[amitslavin]

What does this PR do?

• Adds configuration value for accepting Istio binary path.
• Adds path resolution for Istion monitoring support.

Motivation

We currently try to determine whether a PID represents an Envoy process using this constant path: /proc/PID/bin/envoy.

We identified a situation where Envoy is being used by a symlink path that is different from this constant path.

For that reason I have introduced in this PR 2 things:

• we have decided to use a configuration value for the Envoy path, which will allow us to update the searched path and include PIDs that are Envoy processes.

• we have added path resolution in order to be able to find those cases by default.

Additional Notes

How to use the configuration value?

• Option 1: Add the following environment variable: DD_SERVICE_MONITORING_CONFIG_TLS_ISTIO_ENVOY_PATH="/path_to_envoy"
• Option 2: Add to the configuration file as the following:

  enabled: true
  tls:
    istio:
      enabled: true
      envoy_path: "path_to_envoy"

Performance impact

• Max CPU:
  No negative impact

• Average CPU
  No negative impact

• RSS average
  No negative impact

• Max RSS average
  No negative impact

The image was tested on staging cluster:
No negative impact of the change was observed on the staging cluster.

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=40859590 --os-family=ubuntu

Note: This applies to commit 7c1f2c9

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 0eba5f76-81b8-43d1-8303-bd087bea6767 Metrics dashboard Target profiles

Baseline: 06caaaa
Comparison: a80414e

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
➖	tcp_syslog_to_blackhole	ingress throughput	+2.70	[-10.22, +15.63]	Logs
➖	basic_py_check	% cpu utilization	+1.65	[-1.00, +4.31]	Logs
➖	file_tree	memory utilization	+1.18	[+1.10, +1.27]	Logs
➖	otel_to_otel_logs	ingress throughput	+1.04	[+0.23, +1.86]	Logs
➖	pycheck_1000_100byte_tags	% cpu utilization	+0.30	[-4.57, +5.17]	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.00	[-0.01, +0.01]	Logs
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.00, +0.00]	Logs
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	-0.12	[-1.01, +0.77]	Logs
➖	idle	memory utilization	-0.54	[-0.58, -0.50]	Logs

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".

[hmahmood]

Comment does not seem relevant

[amitslavin]

/merge

[dd-devflow]

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[dd-devflow]

🚂 MergeQueue: pull request added to the queue

The median merge time in main is 23m.

Use /merge -c to cancel this operation!