Consolidate multiple image references in initial containerd image collection

[zhuminyi]

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What does this PR do?

CONTINT-3682

Motivation

When agent starts, as a part of initialization, container images with multiple references could be pulled from containerd runtime. Since the link between imageId, repo-digest and repo-tags are not created in the beginning, some fields such as repo-digest can be missing in the first image reference. In addition, notifyInitialImageEvents will trigger workloadmetastore notify for each image reference which causes stale image in image check process.

The proposed solution is to send notify after all images reference are collected and linked. This will remove any duplicate image metadata or incomplete image metadata.

Additional Notes

Stale images can also be collected from live container check which comes from a race condition during container restart. It will be addressed in another fix.

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

Image check should no longer create a dangling image.

For example, we can launch a customized alpine image:

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: alpine-daemonset
  namespace: default
spec:
  selector:
    matchLabels:
      name: alpine-daemonset
  template:
    metadata:
      labels:
        name: alpine-daemonset
    spec:
      containers:
        - name: alpine
          image: us-east4-docker.pkg.dev/datadog-sandbox/mztest/alpine:test_image_with_fix
          command: ["sh", "-c", "while true; do sleep 1000; done"]

In UI, you should only see one row of running containers

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.

[pr-commenter[bot]]

Bloop Bleep... Dogbot Here

Regression Detector Results

Run ID: d626fc06-1909-4ecd-862a-a6c888f9f3d9 Baseline: 15cf63aa1e85d62bb6cb5b18824b98da77facb25 Comparison: a1b8ddb513f32fcd8504027626e777ea1dfa01aa 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
➖	file_to_blackhole	% cpu utilization	-0.37	[-6.93, +6.18]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	otel_to_otel_logs	ingress throughput	+2.16	[+1.56, +2.75]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+1.19	[-0.21, +2.59]
➖	process_agent_standard_check	memory utilization	+0.46	[+0.40, +0.52]
➖	file_tree	memory utilization	+0.26	[+0.15, +0.38]
➖	tcp_syslog_to_blackhole	ingress throughput	+0.11	[+0.05, +0.17]
➖	trace_agent_json	ingress throughput	+0.03	[+0.00, +0.05]
➖	uds_dogstatsd_to_api	ingress throughput	+0.00	[-0.00, +0.00]
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.00, +0.00]
➖	trace_agent_msgpack	ingress throughput	-0.01	[-0.02, -0.00]
➖	process_agent_standard_check_with_stats	memory utilization	-0.03	[-0.06, +0.01]
➖	idle	memory utilization	-0.22	[-0.26, -0.17]
➖	process_agent_real_time_mode	memory utilization	-0.35	[-0.39, -0.30]
➖	file_to_blackhole	% cpu utilization	-0.37	[-6.93, +6.18]

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".

[AliDatadog]

I think it should still be possible to have an image sent with incomplete metadata. For example, what if we pull an image ? containerd will generate two events and we need to process both before moving on.

[zhuminyi]

I think it should still be possible to have an image sent with incomplete metadata. For example, what if we pull an image ? containerd will generate two events and we need to process both before moving on.

Yes, good catch.

[AliDatadog]

/merge

[dd-devflow[bot]]

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