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feat(observability): alert on a pod whose volume has been stranded on a departed node - #3560
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… a departed node On 2026-07-01 one hcloud volume that stayed attached to a departed node wedged all prod delivery for nine hours, and nothing reported the strand itself. The strand lives in the cloud provider, so the Kubernetes-side VolumeAttachment can look consistent throughout; the rescheduled pod's FailedAttachVolume event is the condition. Add a read-only CronJob in the observability namespace that reads FailedAttachVolume/FailedMount events every five minutes and posts to the shared Slack webhook when a pod has been failing to attach for more than ten minutes, is still failing, and is still not Ready — naming the pod, node, PVC, PV and the CSI message. The three guards (stall window, recency window, pod still not Ready) are what keep a slow-but-successful autoscaler attach quiet; a contract test replays the incident shape and every ordinary shape against a stubbed API and delivery, and each guard is proven by ablation. Fixes #2754 Part of #2363 Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Tried as a user, and self-reviewed, at The detector's user is the CronJob's own container, so the evaluation is the extracted script run exactly as the container runs it — byte-identical apart from the two in-cluster absolute paths, redirected into a sandbox — against a stubbed kube API and a stubbed curl:
Each guard was ablated on a copy and the matching scenario failed for its own reason: dropping the stall guard fires the fresh case, dropping the recency guard fires the historical case, dropping the HTTP-code check turns the 500 into a silent zero, and neutralising the pod-Ready condition fires the slow-but-successful case. (A first ablation pass was itself vacuous — the pattern never matched, nothing was removed, everything passed — so each mutation now asserts exactly one line matched before its verdict counts.) Static validation: the coroot base renders with all five new resources; both cluster overlays build; One thing to know: #2754 was parked on #2755 (bespoke checks had no delivery path). That path now exists by pattern — the CNPG-degraded and posture-staleness checks deliver through the same shared webhook Secret this one mounts — so #2755 stays open as the general item while this detector is deliverable today. The live effect (an actual strand alerting) is observable only on the next real strand; the runbook bullet records what to expect. |
…Ops-managed CronJobs C-0026 is a manual-approval control and this exception is where each reviewed CronJob is enumerated; the new detector runs in observability, which the exception already scopes to, so only the enumeration and the reason prose move. No match scope changes. Part of #2754 Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
…volume-attach alert The rendered authorization surface moves 547 -> 552 documents, purely additive: exactly the alert's ServiceAccount, Secret, ClusterRole, ClusterRoleBinding and CronJob, proven by set difference in both directions and a per-document comparison of every common identity. Grant-bearing objects move 78 -> 81 with the same one-SA/one-narrow- ClusterRole/one-binding shape as the sibling alerts; the ClusterRole is get/list only. The digest is the value the required job reported at the PR head, since the pinned renderer refuses the local toolchain. Part of #2754 Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Authorization-surface re-approval, and how it was established. The What the local toolchain can do is the conservation comparison, rendering all five roots on both sides with one renderer: |
The C-0026 exception's reason now names the stranded-volume-attach alert, and the committed Headlamp mirror is generated from the CRs, so re-run the generator rather than editing the mirror by hand. Part of #2754 Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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No actionable comments were generated in the recent review. 🎉 ℹ️ Recent review info⚙️ Run configurationConfiguration used: Repository YAML (base), Organization UI (inherited) Review profile: ASSERTIVE Plan: Team Run ID: 📒 Files selected for processing (2)
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🧠 Learnings (2)📓 Common learnings📚 Learning: 2026-08-10T13:01:12.782ZApplied to files:
🔇 Additional comments (2)
📝 WalkthroughWalkthroughAdds a read-only Kubernetes CronJob that checks recent Merge Risk: ⚪ Minimal · up to This adds a read-only scheduled alert for persistent volume attach or mount failures, with guarded notification delivery and documented manual remediation. No current merge-blocking risk remains. Important Pre-merge checks failedPlease resolve all errors before merging. Addressing warnings is optional. ❌ Failed checks (1 error, 1 warning)
✅ Passed checks (3 passed)
Full details: Linked Issues checkExplanation The pull request adds a read-only alert, but it does not meet the direct issue's core implementation and acceptance criteria [ Resolution Implement the detector against VolumeAttachments and Nodes. Require an attachment to reference an absent node and persist across two consecutive runs. Grant only get/list access to volumeattachments and nodes. Ensure the alert names the PV, VolumeAttachment, and missing node, then validate normal scale-down behavior as required by [ Full details: Out of Scope Changes checkExplanation The changes are related to the stranded-volume alert. They add the CronJob, read-only RBAC, webhook configuration, tests, documentation, security metadata, and authorization-surface updates. The formatting-only generated ConfigMap change is also related to the GitOps-managed CronJob metadata. Full details: Docstring CoverageExplanation Docstring coverage is 30.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 2 files. (1 skipped: 1 unsupported.) Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
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Inline comments:
In
`@k8s/bases/infrastructure/controllers/coroot/cron-job-stranded-volume-attach-alert.yaml`:
- Line 256: Update the webhook URL validation around the "$WEBHOOK_URL" case to
reject every non-placeholder value whose scheme is not HTTPS before delivery,
including HTTP URLs using port 443; preserve the existing placeholder handling
and only allow actual webhook requests after HTTPS validation.
In
`@k8s/bases/infrastructure/controllers/coroot/secret-stranded-volume-attach-alert.yaml`:
- Line 13: Update the webhook URL validation in the CronJob command to accept
only URLs beginning with https:// before invoking curl, rejecting non-HTTPS
schemes alongside the existing control-character checks. Preserve the current
no-redirect behavior and configured default URL handling.
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Configuration used: Repository YAML (base), Organization UI (inherited)
Review profile: ASSERTIVE
Plan: Team
Run ID: 7098abac-e40d-4c0c-bd70-2349e3f7bd5f
📒 Files selected for processing (12)
.github/workflows/ci.yamldocs/dr/alerting.mdk8s/bases/infrastructure/cluster-security-exceptions/gitops-managed-cronjobs.yamlk8s/bases/infrastructure/controllers/coroot/cluster-role-binding-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/coroot/cluster-role-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/coroot/cron-job-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/coroot/kustomization.yamlk8s/bases/infrastructure/controllers/coroot/secret-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/coroot/service-account-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/kubescape/config-map-headlamp-exceptions.yamlscripts/tests/test-stranded-volume-attach-alert.shscripts/validate-eks-ci-role-policy/main.go
Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.
📜 Review details
🧰 Additional context used
📓 Path-based instructions (1)
Never run a cluster Put a change in the layer that matches its scope
📄 CodeRabbit inference engine (AGENTS.md)
Files:
k8s/bases/infrastructure/controllers/coroot/secret-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/coroot/cluster-role-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/cluster-security-exceptions/gitops-managed-cronjobs.yamlk8s/bases/infrastructure/controllers/coroot/kustomization.yamlk8s/bases/infrastructure/controllers/coroot/service-account-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/coroot/cluster-role-binding-stranded-volume-attach-alert.yamlk8s/bases/infrastructure/controllers/kubescape/config-map-headlamp-exceptions.yamlk8s/bases/infrastructure/controllers/coroot/cron-job-stranded-volume-attach-alert.yaml
🧠 Learnings (1)
📚 Learning: 2026-08-10T13:01:12.782Z
Learnt from: devantler
Repo: devantler-tech/platform PR: 3057
File: .github/workflows/ci.yaml:622-659
Timestamp: 2026-08-10T13:01:12.782Z
Learning: Repository shell tests and scripts must remain compatible with macOS Bash 3.2. Do not use Bash 4+ features such as `mapfile`; use portable constructs, such as a `while IFS= read -r` loop, instead.
Applied to files:
scripts/tests/test-stranded-volume-attach-alert.sh
🪛 ast-grep (0.45.2)
scripts/tests/test-stranded-volume-attach-alert.sh
[warning] 221-221: Writing to or reading from a hardcoded, predictable path under /tmp is vulnerable to symlink and TOCTOU attacks: a local attacker can pre-create the file (or a symlink pointing elsewhere) and hijack or corrupt the contents. Generate a unique, unpredictable temporary file with mktemp instead, e.g. tmpfile="$(mktemp)" (or mktemp -d for directories) and reference "$tmpfile".
Context: "${dir}/tmp/${dir#/}"
Note: [CWE-377] Insecure Temporary File.
(predictable-tmp-file-bash)
🔇 Additional comments (6)
docs/dr/alerting.md (1)
102-115: LGTM!k8s/bases/infrastructure/controllers/coroot/service-account-stranded-volume-attach-alert.yaml (1)
1-6: LGTM!k8s/bases/infrastructure/controllers/coroot/cluster-role-stranded-volume-attach-alert.yaml (1)
1-19: LGTM!k8s/bases/infrastructure/controllers/coroot/cluster-role-binding-stranded-volume-attach-alert.yaml (1)
1-13: LGTM!k8s/bases/infrastructure/controllers/coroot/kustomization.yaml (1)
34-40: LGTM!k8s/bases/infrastructure/cluster-security-exceptions/gitops-managed-cronjobs.yaml (1)
23-24: LGTM!Also applies to: 49-51
…s:// webhook The webhook token travels in the URL path and the network policy allows TCP/443 by port rather than by scheme, so an http:// value would send the token and the alert in the clear. Refuse any non-https destination before delivery; the local/CI placeholder is https too, so it stays inert by the same rule. The contract test pins the refusal. Part of #2754 Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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🧠 Learnings used✅ Action performedReview finished.
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Green review at Re-tried as a user at this head: the contract test runs all nine scenarios green against the extracted script, including the new non-HTTPS refusal, which fails against the previous manifest; the coroot base renders with the guard in the rendered script. CI is green (21 checks). Enqueuing on the merge queue pinned to this head. |
Why
On 2026-07-01 a single volume that stayed attached to a departed node took all production delivery down for nine hours, and nothing reported the strand until the merge queue jammed. The strand lives in the cloud provider, so the Kubernetes-side objects can look consistent the whole time; the only reliable sign is the rescheduled pod repeatedly failing to attach its volume.
What
Adds a read-only scheduled check that reads those attach-failure events every five minutes and posts to the existing Slack alert webhook when a pod has been failing to attach for more than ten minutes, is still failing, and is still not Ready. The alert names the pod, node, claim, volume and the driver's message, so the operator can force-detach in the provider long before it cascades. A contract test replays the 2026-07-01 shape and every ordinary shape (a slow first attach, a failure that stopped, a slow-but-successful scale-up, a deleted pod) so the detector's fire and each quiet verdict are pinned by behaviour, and the runbook records it.
No feature flag: the check only observes and posts, and local/CI carry the placeholder webhook that skips delivery, which is the off state the other bespoke checks already use. Automated force-detach stays out of scope, as #2363 decided.
Fixes #2754
Part of #2363