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[clusteragent/autoscaling] Generate local horizontal recommendations #32882

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@jennchenn jennchenn commented Jan 11, 2025

What does this PR do?

Initial implementation of local recommendation engine. This PR:

  • Adds collection of container resource information to orchestrator containers (this is needed to get request information in autoscaling podwatcher)
  • Changes some loadstore types to allow accessing them directly in local recommendation logic
  • Adds a basic interface to call the local recommendation engine and store results in the autoscaling store
  • Moves some definitions into a new package to avoid import cycle
    • Namely autoscaling podwatcher definitions - can also move the interface out of local and pass pod information directly into the recommendation logic if that makes more sense
  • Adds new autoscaling.workload.local.horizontal_scaling_recommended_replicas telemetry metric to track local recommendations

Motivation

Support local fallback.

Describe how you validated your changes

  1. Deploy the node agent (at least 7.60.0) + cluster agent with these changes
  2. Verify that you are able to see local recommendations generated (e.g. via the telemetry metric)
  3. Check that these recommendations ~ match recommendations from product for the same workload
image

Possible Drawbacks / Trade-offs

  • Increased memory consumption due to collection of container resource information in the cluster agent -> are there alternatives that should be explored here?
  • Current consumption of loadstore metric information is not very optimized: currently we loop through the entire results array to find each pod
    • we could consider preprocessing and convert the results to a map with podName as key; or
    • we can change how the results are formatted and return a map directly from the loadstore
  • Not currently using the common autoscaling API interface types

Additional Notes

This PR does not include:

  1. Config option to gate local fallback behind
  2. Logic to apply the local recommendations when in failure state
  3. Support for external recommenders
  4. Use of shared API interface for recommenders
  5. Test for full local horizontal recommendation calculation (with mocked podwatcher/loadstore)

@jennchenn jennchenn added team/containers changelog/no-changelog qa/done QA done before merge and regressions are covered by tests component/autoscaling labels Jan 11, 2025
@github-actions github-actions bot added the long review PR is complex, plan time to review it label Jan 11, 2025
@jennchenn jennchenn added this to the 7.63.0 milestone Jan 11, 2025
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agent-platform-auto-pr bot commented Jan 11, 2025

Uncompressed package size comparison

Comparison with ancestor edd9ae272a4ea05c1f9d6941b11b73d159b67cae

Diff per package
package diff status size ancestor threshold
datadog-agent-amd64-deb 0.01MB ⚠️ 929.15MB 929.14MB 0.50MB
datadog-agent-x86_64-rpm 0.01MB ⚠️ 938.81MB 938.80MB 0.50MB
datadog-agent-x86_64-suse 0.01MB ⚠️ 938.81MB 938.80MB 0.50MB
datadog-dogstatsd-amd64-deb 0.00MB 58.93MB 58.93MB 0.50MB
datadog-dogstatsd-arm64-deb 0.00MB 56.44MB 56.44MB 0.50MB
datadog-dogstatsd-x86_64-rpm 0.00MB 59.01MB 59.01MB 0.50MB
datadog-dogstatsd-x86_64-suse 0.00MB 59.01MB 59.01MB 0.50MB
datadog-iot-agent-aarch64-rpm 0.00MB 90.11MB 90.11MB 0.50MB
datadog-heroku-agent-amd64-deb 0.00MB 477.44MB 477.44MB 0.50MB
datadog-iot-agent-arm64-deb 0.00MB 90.04MB 90.04MB 0.50MB
datadog-iot-agent-x86_64-rpm -0.00MB 94.06MB 94.07MB 0.50MB
datadog-iot-agent-x86_64-suse -0.00MB 94.06MB 94.06MB 0.50MB
datadog-agent-arm64-deb -0.00MB 915.81MB 915.81MB 0.50MB
datadog-agent-aarch64-rpm -0.00MB 925.45MB 925.45MB 0.50MB
datadog-iot-agent-amd64-deb -0.00MB 93.99MB 94.00MB 0.50MB

Decision

⚠️ Warning

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agent-platform-auto-pr bot commented Jan 11, 2025

Test changes on VM

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

inv aws.create-vm --pipeline-id=53705519 --os-family=ubuntu

Note: This applies to commit 7804889

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cit-pr-commenter bot commented Jan 12, 2025

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 658ac8a6-c531-46f9-b70f-e960cef61c24

Baseline: edd9ae2
Comparison: 7804889
Diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf experiment goal Δ mean % Δ mean % CI trials links
quality_gate_logs % cpu utilization +3.15 [+0.06, +6.23] 1 Logs
uds_dogstatsd_to_api_cpu % cpu utilization +1.29 [+0.37, +2.21] 1 Logs
quality_gate_idle_all_features memory utilization +0.27 [+0.22, +0.32] 1 Logs bounds checks dashboard
file_to_blackhole_1000ms_latency_linear_load egress throughput +0.13 [-0.34, +0.59] 1 Logs
file_to_blackhole_0ms_latency_http1 egress throughput +0.07 [-0.84, +0.98] 1 Logs
quality_gate_idle memory utilization +0.06 [+0.02, +0.09] 1 Logs bounds checks dashboard
file_to_blackhole_500ms_latency egress throughput +0.05 [-0.73, +0.83] 1 Logs
file_to_blackhole_100ms_latency egress throughput +0.02 [-0.69, +0.74] 1 Logs
file_to_blackhole_300ms_latency egress throughput -0.01 [-0.64, +0.63] 1 Logs
tcp_dd_logs_filter_exclude ingress throughput -0.01 [-0.03, +0.01] 1 Logs
uds_dogstatsd_to_api ingress throughput -0.01 [-0.28, +0.26] 1 Logs
file_to_blackhole_0ms_latency egress throughput -0.01 [-0.93, +0.90] 1 Logs
file_to_blackhole_0ms_latency_http2 egress throughput -0.01 [-0.89, +0.86] 1 Logs
file_tree memory utilization -0.05 [-0.10, -0.00] 1 Logs
file_to_blackhole_1000ms_latency egress throughput -0.85 [-1.65, -0.05] 1 Logs
tcp_syslog_to_blackhole ingress throughput -1.84 [-2.02, -1.65] 1 Logs

Bounds Checks: ✅ Passed

perf experiment bounds_check_name replicates_passed links
file_to_blackhole_0ms_latency lost_bytes 10/10
file_to_blackhole_0ms_latency memory_usage 10/10
file_to_blackhole_0ms_latency_http1 lost_bytes 10/10
file_to_blackhole_0ms_latency_http1 memory_usage 10/10
file_to_blackhole_0ms_latency_http2 lost_bytes 10/10
file_to_blackhole_0ms_latency_http2 memory_usage 10/10
file_to_blackhole_1000ms_latency memory_usage 10/10
file_to_blackhole_1000ms_latency_linear_load memory_usage 10/10
file_to_blackhole_100ms_latency lost_bytes 10/10
file_to_blackhole_100ms_latency memory_usage 10/10
file_to_blackhole_300ms_latency lost_bytes 10/10
file_to_blackhole_300ms_latency memory_usage 10/10
file_to_blackhole_500ms_latency lost_bytes 10/10
file_to_blackhole_500ms_latency memory_usage 10/10
quality_gate_idle intake_connections 10/10 bounds checks dashboard
quality_gate_idle memory_usage 10/10 bounds checks dashboard
quality_gate_idle_all_features intake_connections 10/10 bounds checks dashboard
quality_gate_idle_all_features memory_usage 10/10 bounds checks dashboard
quality_gate_logs intake_connections 10/10
quality_gate_logs lost_bytes 10/10
quality_gate_logs memory_usage 10/10

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

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

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".

CI Pass/Fail Decision

Passed. All Quality Gates passed.

  • quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
  • quality_gate_logs, bounds check lost_bytes: 10/10 replicas passed. Gate passed.

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cit-pr-commenter bot commented Jan 14, 2025

Go Package Import Differences

Baseline: edd9ae2
Comparison: 7804889

binaryosarchchange
cluster-agentlinuxamd64
+2, -0
+github.com/DataDog/datadog-agent/pkg/clusteragent/autoscaling/workload/common
+github.com/DataDog/datadog-agent/pkg/clusteragent/autoscaling/workload/local
cluster-agentlinuxarm64
+2, -0
+github.com/DataDog/datadog-agent/pkg/clusteragent/autoscaling/workload/common
+github.com/DataDog/datadog-agent/pkg/clusteragent/autoscaling/workload/local

@@ -246,6 +246,7 @@ func parsePodContainers(
if containerSpec != nil {
env = extractEnvFromSpec(containerSpec.Env)
resources = extractResources(containerSpec)
podContainer.Resources = resources
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Not sure this is required in case of Kubelet collector

c := workloadmeta.OrchestratorContainer{
Name: container.Name,
}
if cpuReq, found := container.Resources.Requests[corev1.ResourceCPU]; found {
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Code is duplicated with already existing Kubelet container parsing. Perhaps we can do something to share the code.

containersList = append(containersList, c)
}

// If this list is empty, we want to return nil instead of an empty list
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Is there a reason for that? From the code I don't even think it's possible except if the POD has 0 container (which is not possible).

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Added this because of a test case failing, but you're right the test case defined a pod with 0 containers - removed!

const (
staleDataThresholdSeconds = 180 // 3 minutes
containerCPUUsageMetricName = "container.cpu.usage"
containerMemoryUsageMetricName = "container.memory.usage"
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Note for later: we may want to tweak that. For horizontal scaling, perhaps working_set could be make sense if we want to be closer to OOM limits.

}
}

func newResourceRecommenderSettings(target datadoghq.DatadogPodAutoscalerTarget) (*resourceRecommenderSettings, error) {
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I think this part will change as we may want a specific fallback target. Another point is that it's also validating targets.
It would perhaps not expect this to be done there, as validation could be done way earlier, but if it's done there, then I would expect more relevant error messages for users.

)

type resourceRecommenderSettings struct {
MetricName string
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Same here, do we need these fields to be public?

}

// ReinitLoadstore reinitializes the loadstore for the local recommender
func (l *Recommender) ReinitLoadstore(ctx context.Context) error {
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I'm not sure I understand why we need this? Is there any issue with initializing this in the new function?

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Changed this bit of logic; original motivation was that we need to check the store is not nil before calling store.GetMetricsRaw. This check is now done in the process loop directly (fixes some of the other comments above as well)

return nil, fmt.Errorf("Invalid target type: %s", target.Type)
}

func getOptionsFromPodResource(target *datadoghq.DatadogPodAutoscalerResourceTarget) (*resourceRecommenderSettings, error) {
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I think we need to split the code for the metrics/calculation and the settings/setup part in different files.

ID string
Name string
Image ContainerImage
Resources ContainerResources
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This is all because the metric we send is absolute and not relative right?

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Discussed briefly online - yes (currently using container.cpu.usage from the agent so to calculate utilization we require container requests)


//go:build kubeapiserver

package shared
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nit: usually more named common than shared

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