avav25/helm-procedures

Helm Procedures — diff, atomic upgrade, rollback

Knowledge reference for Helm operations used by infrastructure-change workflows. Covers chart linting, diff preview via the helm-diff plugin, the safe upgrade pattern (--atomic + --wait), rollback, and inspection of release state.

Inspect current release state

helm list -n <namespace>
helm get values <release-name> -n <namespace>
helm history <release-name> -n <namespace>

Record current image tags, replica counts, and values-file diffs as the rollback baseline before any upgrade.

Lint the chart

Before any diff or upgrade, lint:

helm lint <chart-path>

Lint failures should block the workflow.

Diff preview — helm-diff plugin

The helm-diff plugin is the recommended tool for previewing chart changes before upgrade. Install once:

helm plugin install https://github.com/databus23/helm-diff

Then preview:

helm diff upgrade <release> <chart-path> -n <namespace> -f <values-file>

Diff summary format

When presenting a diff for review, summarise as:

## Helm Diff Summary
| Object | Action | Key Changes |
|--------|--------|-------------|
| Deployment/X | changed | replicas: 1->2, image: v1->v2 |
| Service/Y | added | port 8080 |
| Secret/Z | changed | keys modified |

WARNING — Critical changes:
- [deployment restart expected]
- [secret reference changed]

Downtime risk: [yes/no]

Atomic upgrade — the safe default

helm upgrade <release> <chart-path> -n <namespace> -f <values-file> \
  --atomic --timeout 5m --wait

Flag rationale:

• --atomic — auto-rolls back on failure (recommended for production). If any resource fails to reach Ready within --timeout, Helm reverts the entire release to the prior revision.
• --timeout 5m — should match the application's readiness-probe budget, with headroom for image pull and init containers. Tune per environment.
• --wait — blocks until all resources reach Ready. Without --wait, the upgrade command returns immediately after the API server accepts the manifests, hiding rollout failures from the operator.

Install vs upgrade

helm install <release> <chart-path> -n <namespace> -f <values-file> \
  --atomic --timeout 5m --wait

For idempotent flows, prefer helm upgrade --install which installs if missing and upgrades if present.

Rollback

helm rollback <release> <previous-revision> -n <namespace>

Use helm history to find the target revision number. Rollback creates a new revision (it does not delete the failed one), so the release history grows monotonically.

For releases deployed with --atomic, an automatic rollback already executed on failure — manual rollback is needed only for issues detected after the upgrade reports success.

Values-file conventions

Common values-file layouts:

• values.yaml — chart defaults, checked into the chart repo
• values-<env>.yaml (e.g., values-prod.yaml, values-staging.yaml) — per-environment overrides
• values-secrets.yaml — encrypted with SOPS or sealed-secrets, never committed in plaintext

Pass multiple values files in precedence order (later wins):

helm upgrade <release> <chart-path> -n <namespace> \
  -f values.yaml -f values-prod.yaml -f values-secrets.yaml \
  --atomic --timeout 5m --wait

When this applies

| Phase | Apply this knowledge | |---|---| | Step 3 — Review current state | helm list, helm get values, helm history | | Step 4 — Implement | Modify values.yaml / templates; helm lint <chart-path> | | Step 5 — Plan review | helm diff upgrade and diff-summary format | | Step 6 — Apply | helm upgrade ... --atomic --timeout 5m --wait | | Step 8 — Rollback | helm rollback <release> <revision> |

Integration

• Used by: /infra-change (Steps 3, 4, 5, 6, 8 — Helm release lifecycle), /deploy-production, /deploy-staging (when charts are the deploy unit)
• Companion knowledge: @deployment-procedures (rolling/canary/blue-green strategy choice), @gitops-detection (Argo CD / Flux own the apply gate when GitOps is in use)
• External references: Helm docs, helm-diff plugin, Helm upgrade flags