fix: OOMKilled alert for: 0m -> 15m

forgejo_admin commented

2026-03-27 00:16:37 +00:00

Owner

Summary

The OOMKilled alert rule fires on kube_pod_container_status_last_terminated_reason{reason="OOMKilled"} which persists indefinitely after pod recovery. With for: 0m, the alert fires forever on historical OOM state even after the pod is healthy for days. Changing to for: 15m allows the alert to auto-resolve after a deployment rollout clears the stale metric.

Changes

terraform/main.tf line 266: for = "0m" changed to for = "15m" on the OOMKilled alert rule in helm_release.kube_prometheus_stack

Test Plan

tofu fmt passes
tofu validate passes
tofu plan -lock=false shows only the for: duration change on helm_release.kube_prometheus_stack (0 to add, 1 to change, 0 to destroy)
Post-merge: OOMKilled alert clears in AlertManager after PR 1 rollout

tofu plan Output

Plan: 0 to add, 1 to change, 0 to destroy.

  ~ resource "helm_release" "kube_prometheus_stack" {
      ~ values = [
          ~ <<-EOT
              - "alert": "OOMKilled"
                "expr": "kube_pod_container_status_last_terminated_reason{reason=\"OOMKilled\"} > 0"
          -       "for": "0m"
          +       "for": "15m"
                "labels":
                  "severity": "critical"
          EOT,
        ]
    }

Review Checklist

Passed automated review-fix loop
No secrets committed
No unnecessary file changes
Commit messages are descriptive

Discovered Scope

PodRestartStorm rule at lines 252-262 also uses for = "0m" -- same staleness class. Separate ticket needed.

Closes #171
PR ordering: This is PR 2 of 2. PR 1 (pal-e-deployments memory bump 64Mi to 128Mi) has already merged.

## Summary The OOMKilled alert rule fires on `kube_pod_container_status_last_terminated_reason{reason="OOMKilled"}` which persists indefinitely after pod recovery. With `for: 0m`, the alert fires forever on historical OOM state even after the pod is healthy for days. Changing to `for: 15m` allows the alert to auto-resolve after a deployment rollout clears the stale metric. ## Changes - `terraform/main.tf` line 266: `for = "0m"` changed to `for = "15m"` on the OOMKilled alert rule in `helm_release.kube_prometheus_stack` ## Test Plan - [x] `tofu fmt` passes - [x] `tofu validate` passes - [x] `tofu plan -lock=false` shows only the `for:` duration change on `helm_release.kube_prometheus_stack` (0 to add, 1 to change, 0 to destroy) - [ ] Post-merge: OOMKilled alert clears in AlertManager after PR 1 rollout ### tofu plan Output ``` Plan: 0 to add, 1 to change, 0 to destroy. ~ resource "helm_release" "kube_prometheus_stack" { ~ values = [ ~ <<-EOT - "alert": "OOMKilled" "expr": "kube_pod_container_status_last_terminated_reason{reason=\"OOMKilled\"} > 0" - "for": "0m" + "for": "15m" "labels": "severity": "critical" EOT, ] } ``` ## Review Checklist - [x] Passed automated review-fix loop - [x] No secrets committed - [x] No unnecessary file changes - [x] Commit messages are descriptive ## Discovered Scope - `PodRestartStorm` rule at lines 252-262 also uses `for = "0m"` -- same staleness class. Separate ticket needed. ## Related - Closes #171 - PR ordering: This is PR 2 of 2. PR 1 (pal-e-deployments memory bump 64Mi to 128Mi) has already merged.

forgejo_admin added 1 commit

2026-03-27 00:16:37 +00:00

fix: increase OOMKilled alert for: duration from 0m to 15m

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86c3df3d86

The OOMKilled alert rule fires on kube_pod_container_status_last_terminated_reason
which persists after pod recovery. With for: 0m, the alert fires forever on
historical OOM state even after the pod is healthy. Changing to for: 15m allows
the alert to auto-resolve after a deployment rollout clears the stale metric.

Refs: #171

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

forgejo_admin commented

2026-03-27 00:17:00 +00:00

Author

Owner

Review: APPROVED

Diff: 1 file, 1 line changed. for = "0m" to for = "15m" on the OOMKilled alert rule at line 266 of terraform/main.tf.

Verified:

Change is scoped exactly to the OOMKilled alert for: duration -- no other lines touched
tofu fmt passes
tofu validate passes
tofu plan -lock=false shows 0 to add, 1 to change, 0 to destroy -- only the helm_release.kube_prometheus_stack values diff
No secrets committed
PR is mergeable

No findings. Clean single-line fix matching the issue spec exactly.

## Review: APPROVED **Diff:** 1 file, 1 line changed. `for = "0m"` to `for = "15m"` on the OOMKilled alert rule at line 266 of `terraform/main.tf`. **Verified:** - Change is scoped exactly to the OOMKilled alert `for:` duration -- no other lines touched - `tofu fmt` passes - `tofu validate` passes - `tofu plan -lock=false` shows 0 to add, 1 to change, 0 to destroy -- only the `helm_release.kube_prometheus_stack` values diff - No secrets committed - PR is mergeable **No findings.** Clean single-line fix matching the issue spec exactly.

forgejo_admin commented

2026-03-27 00:18:29 +00:00

Author

Owner

PR #185 Review

DOMAIN REVIEW

Tech stack: Terraform (OpenTofu) / Helm / Prometheus alerting rules

This is a single-line change to the kube_prometheus_stack Helm release values in terraform/main.tf. The OOMKilled alert rule's for field is changed from "0m" to "15m".

Technical assessment:

The kube_pod_container_status_last_terminated_reason{reason="OOMKilled"} metric persists the last termination reason even after pod recovery. With for: 0m, this fires instantly and never resolves -- the PR body correctly diagnoses this staleness class.
for: 15m means the condition must hold for 15 continuous minutes before firing. After a deployment rollout clears the stale metric (pod restarts reset last_terminated_reason), the alert resolves within one evaluation cycle.
15 minutes is a reasonable duration -- long enough to filter transient metric staleness, short enough to still catch genuine recurring OOM conditions.
The tofu plan output confirms the change is isolated to the for duration on the OOMKilled rule with 0 to add, 1 to change, 0 to destroy.

Discovered scope properly tracked: The PR body correctly identifies that PodRestartStorm (line 252-254) has the same for = "0m" pattern and defers it to a separate ticket. Good discipline.

BLOCKERS

None.

No new functionality requiring test coverage (this is a config value change on an existing Helm release)
No user input paths
No secrets or credentials
No DRY violations

NITS

None. The change is minimal and well-scoped.

SOP COMPLIANCE

Branch named after issue (171-oomkilled-alert-for-duration references #171)
PR body follows template (Summary, Changes, Test Plan, Related, Discovered Scope)
tofu plan -lock=false output included per PR conventions
tofu fmt and tofu validate confirmed passing
Discovered scope documented and deferred (PodRestartStorm same staleness class)
No secrets committed
No unnecessary file changes (1 file, 1 line changed)
Commit messages are descriptive
Related references parent issue (Closes #171)
Plan slug not required (bug fix -- straight to board per kanban flow)

PROCESS OBSERVATIONS

Change failure risk: Very low. Single value change on a Prometheus alert rule duration. The tofu plan confirms no resource additions or deletions.
Deployment frequency: No impact. Standard Terraform apply cycle.
MTTR improvement: This PR directly improves MTTR by eliminating alert noise from stale OOMKilled metrics. When the alert fires post-merge, it will represent a genuine ongoing condition rather than historical state.
Two-PR coordination: PR 1 (pal-e-deployments memory bump 64Mi to 128Mi) addresses the root cause. PR 2 (this one) addresses the alert staleness. Good decomposition -- fixes the symptom and the signal independently.

VERDICT: APPROVED

## PR #185 Review ### DOMAIN REVIEW **Tech stack**: Terraform (OpenTofu) / Helm / Prometheus alerting rules This is a single-line change to the `kube_prometheus_stack` Helm release values in `terraform/main.tf`. The OOMKilled alert rule's `for` field is changed from `"0m"` to `"15m"`. **Technical assessment**: - The `kube_pod_container_status_last_terminated_reason{reason="OOMKilled"}` metric persists the last termination reason even after pod recovery. With `for: 0m`, this fires instantly and never resolves -- the PR body correctly diagnoses this staleness class. - `for: 15m` means the condition must hold for 15 continuous minutes before firing. After a deployment rollout clears the stale metric (pod restarts reset `last_terminated_reason`), the alert resolves within one evaluation cycle. - 15 minutes is a reasonable duration -- long enough to filter transient metric staleness, short enough to still catch genuine recurring OOM conditions. - The `tofu plan` output confirms the change is isolated to the `for` duration on the OOMKilled rule with 0 to add, 1 to change, 0 to destroy. **Discovered scope properly tracked**: The PR body correctly identifies that `PodRestartStorm` (line 252-254) has the same `for = "0m"` pattern and defers it to a separate ticket. Good discipline. ### BLOCKERS None. - No new functionality requiring test coverage (this is a config value change on an existing Helm release) - No user input paths - No secrets or credentials - No DRY violations ### NITS None. The change is minimal and well-scoped. ### SOP COMPLIANCE - [x] Branch named after issue (`171-oomkilled-alert-for-duration` references #171) - [x] PR body follows template (Summary, Changes, Test Plan, Related, Discovered Scope) - [x] `tofu plan -lock=false` output included per PR conventions - [x] `tofu fmt` and `tofu validate` confirmed passing - [x] Discovered scope documented and deferred (PodRestartStorm same staleness class) - [x] No secrets committed - [x] No unnecessary file changes (1 file, 1 line changed) - [x] Commit messages are descriptive - [x] Related references parent issue (Closes #171) - [x] Plan slug not required (bug fix -- straight to board per kanban flow) ### PROCESS OBSERVATIONS - **Change failure risk**: Very low. Single value change on a Prometheus alert rule duration. The tofu plan confirms no resource additions or deletions. - **Deployment frequency**: No impact. Standard Terraform apply cycle. - **MTTR improvement**: This PR directly improves MTTR by eliminating alert noise from stale OOMKilled metrics. When the alert fires post-merge, it will represent a genuine ongoing condition rather than historical state. - **Two-PR coordination**: PR 1 (pal-e-deployments memory bump 64Mi to 128Mi) addresses the root cause. PR 2 (this one) addresses the alert staleness. Good decomposition -- fixes the symptom and the signal independently. ### VERDICT: APPROVED