Fix ECS Fargate processes not being associated with containers

[sblumenthal]

What does this PR do?

Fixes a bug where sometimes the process data generated for an ECS Fargate container is missing the container tags

Motivation

https://datadoghq.atlassian.net/browse/CONS-6242

Additional Notes

It appears that the problem was due to regex parsing, while debugging I found instances where the fargate container ID was {32}-{9}, but we were explicitly only looking at {32}-{10}. I cannot find any information on the definition of the fargate container ID format, so while this addresses the situation we came across in the support ticket, I do not know if there are other cases we have not run into yet.

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

I was able to reliably replicate this issue using the python container using the following task container definition:

        {
            "name": "api",
            "image": "public.ecr.aws/docker/library/python",
            "essential": false,
            "command": [
                "python",
                "-m",
                "http.server",
                "8080"
            ]
        }

Add this container definition as another container here, after the redis container definition, and deploy to an ECS fargate cluster

Verify that the container shows up on the live containers page, and that the process data shows up attached to this container, like so:

Also, to make sure the original bug that we ran into was being hit, log into the AWS console and navigate to the tasks page for you cluster, find the task that contains the python container, and validate that the container runtime ID matches the format that caused the issue in the first place:

The above container reliably triggered the issue, across multiple clusters. However, if it does not result in a container ID that is one character short, then it is worth noting that the QA for this has already been done in a cluster where we were able to reproduce the issue, and has been validated

[agent-platform-auto-pr]

[Fast Unit Tests Report]

On pipeline 31024874 (CI Visibility). The following jobs did not run any unit tests:

Jobs:

• tests_windows-x64

If you modified Go files and expected unit tests to run in these jobs, please double check the job logs. If you think tests should have been executed reach out to #agent-developer-experience

[AliDatadog]

Suggested change

	fileContent: ecsFargateCgroup,
	fileContent: ecsFargateCgroupShort,

[sblumenthal]

Yup, just noticed failing jobs, my bad

[rtrieu]

Looks good!

[sblumenthal]

/merge

[dd-devflow]

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[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=31024874 --os-family=ubuntu

[dd-devflow]

🚂 MergeQueue

Added to the queue.

This build is next! (estimated merge in less than 28m)

Use /merge -c to cancel this operation!

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 33621e2d-713c-433c-b195-a22da630ebbb
Baseline: b238404
Comparison: a6a7dec

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
➖	file_to_blackhole	% cpu utilization	+3.12	[-3.23, +9.47]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	file_to_blackhole	% cpu utilization	+3.12	[-3.23, +9.47]
➖	pycheck_1000_100byte_tags	% cpu utilization	+2.09	[-2.84, +7.01]
➖	tcp_syslog_to_blackhole	ingress throughput	+2.07	[+1.98, +2.16]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+1.82	[-1.06, +4.70]
➖	basic_py_check	% cpu utilization	+0.65	[-1.78, +3.08]
➖	process_agent_real_time_mode	memory utilization	+0.51	[+0.47, +0.55]
➖	idle	memory utilization	+0.42	[+0.38, +0.45]
➖	process_agent_standard_check_with_stats	memory utilization	+0.25	[+0.21, +0.29]
➖	otel_to_otel_logs	ingress throughput	+0.04	[-0.38, +0.45]
➖	trace_agent_json	ingress throughput	+0.02	[-0.02, +0.05]
➖	uds_dogstatsd_to_api	ingress throughput	+0.00	[-0.20, +0.20]
➖	trace_agent_msgpack	ingress throughput	-0.00	[-0.02, +0.02]
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.01	[-0.05, +0.03]
➖	process_agent_standard_check	memory utilization	-0.13	[-0.18, -0.09]
➖	file_tree	memory utilization	-0.16	[-0.25, -0.08]

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".