8aa400a5d4
Add 37 new entries and update 7 existing entries across 13 topic files. Major contributions from agent-runtimes (K8s secrets, CI, Docker gotchas), cluster-bootstrap (ArgoCD SSA, etcd tuning, DB migrations, Compose networking), and cluster-apps/octopus-deploy (Helm vs raw manifests, ArgoCD source types). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
30 lines
1.8 KiB
Markdown
30 lines
1.8 KiB
Markdown
# Helm Charts
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## Schema Validation
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- **Always validate values against the chart schema before committing.** Run `helm show values <repo>/<chart> --version <ver>` to check the actual structure.
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- Helm chart schemas change between versions — field names and nesting can differ from documentation or online examples.
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- A quick `helm template` test locally catches schema errors before deployment.
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- `additionalProperties: false` in chart schemas means any extra keys at the wrong nesting level cause a hard failure.
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## Version Verification
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- Run `helm search repo` or check upstream docs to confirm latest stable versions
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- Don't rely on memory for chart versions — they go stale quickly
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- Check compatibility matrices between chart version, app version, and other cluster components
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## Multi-Source Applications
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- ArgoCD multi-source Applications use `$ref` syntax to combine external Helm charts with Git-stored values files
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- Keep values files in Git alongside the ArgoCD Application manifest
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## Timeout Handling
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- Under cluster pressure (many events, etcd busy), default Helm timeouts may not be enough
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- Increase timeout for initial installs (e.g., 10m instead of 5m)
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- `helm upgrade --install` is idempotent — retries are safe
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## Prefer Raw Manifests Over Complex Helm Charts for Simple Workloads
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When a Helm chart introduces infrastructure dependencies beyond the application itself (NFS servers, CSI drivers, pre-install hooks with trust bootstrapping, RWX PVC requirements), evaluate whether a raw Deployment or StatefulSet with environment variables would be simpler. Complex charts that bundle infrastructure assumptions are fragile on non-standard clusters. If the application image handles its own configuration via env vars, a raw manifest is often more reliable and debuggable.
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