DevContainer User
56 lines
2.1 KiB
Markdown
56 lines
2.1 KiB
Markdown
# ADR 003: Graceful Degradation for Optional CRDs
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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 uses VolumeSnapshot and VolumeSnapshotClass CRDs from `snapshot.storage.k8s.io/v1`. These CRDs are part of the Kubernetes Volume Snapshot feature, which is optional — not all clusters have the snapshot controller installed.
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The plugin should work on clusters without snapshot support, showing storage classes, volumes, metrics, and benchmarks without the snapshots page. The CRD fetch is wrapped in `try/catch`; if it fails, the `snapshotCrdAvailable` flag is set to `false`.
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---
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## Decision
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Implement graceful degradation for optional CRDs. The snapshot API calls are wrapped in `try/catch` within the data context. When the snapshot CRDs are not installed:
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- `snapshotCrdAvailable` is set to `false`
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- Snapshot-related data arrays are empty
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- The Snapshots page shows an informational message rather than an error
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- All other plugin features remain fully functional
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---
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## Consequences
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- ✅ Plugin works on clusters without snapshot CRDs installed
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- ✅ No error state for missing optional features — clean informational messaging
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- ✅ Clear user feedback about what features are available
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- ✅ Core features (volumes, storage classes, metrics, benchmarks) always work
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- ⚠️ Two code paths (with/without snapshots) to maintain and test
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- ⚠️ Snapshot data might silently fail for reasons other than missing CRDs (e.g., RBAC issues)
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---
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## Alternatives Considered
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1. **Require snapshot CRDs (hard dependency)** — Rejected. Too restrictive; many clusters do not have the snapshot controller installed.
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2. **Feature detection via API discovery before fetching** — Considered, but `try/catch` on the actual fetch is simpler and catches all failure modes including RBAC restrictions.
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3. **Disable snapshots page entirely when CRDs missing** — Rejected. Showing an informational message explaining how to enable snapshots is better UX than silently hiding the page.
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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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