DevContainer User
61 lines
2.5 KiB
Markdown
61 lines
2.5 KiB
Markdown
# ADR 002: Read-Only Plugin with Benchmark Exception
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**Status**: Accepted
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**Date**: 2026-03-05
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**Deciders**: Development Team
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---
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## Context
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The plugin is primarily a read-only observability tool for TNS CSI storage. However, it includes a Benchmark feature that runs kbench (FIO-based storage benchmarks) against storage classes. Running benchmarks requires creating temporary Kubernetes resources: a PVC for the test volume and a Job running the kbench container.
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These resources are tagged with `app.kubernetes.io/managed-by=headlamp-tns-csi-plugin` for lifecycle tracking. The benchmark workflow includes:
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1. `buildPvcManifest()` — Create PVC spec for test volume
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2. `createPvc()` — Create the PVC in the cluster
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3. `buildJobManifest()` — Create Job spec for kbench container
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4. `createJob()` — Create the Job in the cluster
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5. Poll for Job completion
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6. `fetchKbenchLogs()` — Retrieve benchmark output from pod logs
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7. `parseKbenchLog()` — Parse FIO results from kbench output
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8. `deleteJob()` — Clean up the benchmark Job
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9. `deletePvc()` — Clean up the test PVC
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---
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## Decision
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The plugin is read-only for all storage observability features. The sole exception is the Benchmark feature, which creates and deletes temporary PVC + Job resources. All created resources are labeled for identification and cleaned up after benchmark completion. The benchmark is triggered explicitly by user action (button on StorageClass detail page via `registerDetailsViewHeaderAction`).
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---
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## Consequences
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- ✅ Minimal RBAC requirements for normal operation (read-only)
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- ✅ Benchmark is opt-in and requires explicit user action
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- ✅ Resources are auto-cleaned after benchmark completion
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- ✅ `managed-by` label enables easy identification of plugin-created resources
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- ⚠️ Requires additional RBAC permissions (create/delete Jobs and PVCs) for benchmark feature
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- ⚠️ Failed cleanup leaves orphaned resources — mitigated by `listKbenchJobs()` which finds orphaned resources by label for manual cleanup
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---
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## Alternatives Considered
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1. **No benchmark feature (fully read-only)** — Rejected. Storage performance testing is a key use case for storage administrators evaluating CSI drivers.
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2. **External benchmark tool with results import** — Rejected. Poor user experience requiring context-switching between tools.
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3. **Benchmark as a separate plugin** — Rejected. Benchmark results are tied to storage class context and benefit from shared data in the plugin.
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---
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## Changelog
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| Date | Change |
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|------|--------|
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| 2026-03-05 | Initial decision |
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