[USM] Add envoy configuration value

[amitslavin]

What does this PR do?

Add configuration value for envoyCmd.

Motivation

Fix the issue where the Envoy path is not set to the default value, causing Istio support to fail.

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=38511427 --os-family=ubuntu

Note: This applies to commit 3c9bdd4

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 89debf1f-4d5c-4ab5-abef-51dcbb331261 Metrics dashboard Target profiles

Baseline: 662545f
Comparison: 3c9bdd4

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
➖	file_tree	memory utilization	+0.41	[+0.30, +0.51]	Logs
➖	otel_to_otel_logs	ingress throughput	+0.33	[-0.48, +1.15]	Logs
➖	pycheck_1000_100byte_tags	% cpu utilization	+0.06	[-4.82, +4.93]	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
➖	idle	memory utilization	-0.39	[-0.43, -0.36]	Logs
➖	basic_py_check	% cpu utilization	-0.47	[-3.09, +2.16]	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	-1.26	[-13.66, +11.14]	Logs
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	-2.11	[-2.99, -1.23]	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".

[guyarb]

Suggested change

	cfg.BindEnvAndSetDefault(join(smNS, "tls", "istio", "envoy_path"), "")
	cfg.BindEnv(join(smNS, "tls", "istio", "envoy_path"), "")

[guyarb]

Overall, that's a good change
I'm missing some documentation and reasoning

What about better path resolution? Do you defer it for a followup PR?

[amitslavin]

Issue is being handled in the following PR: #27400