Upgrading Releases

1. Upgrading Release

helm upgrade api ./chart -n web -f values-prod.yaml

Flag	Behavior
`--install / -i`	Install if release missing, otherwise upgrade (idempotent for CI)

Flag	Behavior
`--force`	Replace resources via delete + recreate when patch is rejected

Warning: --force can cause downtime — Services are recreated, losing ClusterIP; PVCs may be deleted. Use sparingly.

Flag	Effect
`--reset-values`	Discard previous user values; use chart defaults + new `-f`/`--set`

Flag	Effect
`--reuse-values`	Keep previous values; merge new `--set` on top
Default (3.x)	If no `-f` or `--set` provided, reuses; otherwise resets and applies new only

Note: Helm 3 default behavior surprises many users. Always explicitly pass -f values.yaml + --reset-values for reproducible upgrades.

helm upgrade api bitnami/nginx --version 18.1.0 \
  --reuse-values --set image.tag=1.27.0

Flag	Effect
`--atomic`	Implies `--wait`; auto-rolls back on failure
`--cleanup-on-fail`	Delete newly created resources from failed upgrade

helm upgrade --install api ./chart \
  --atomic --cleanup-on-fail --timeout 10m \
  -f values-prod.yaml

Flag	Behavior
`--history-max N`	Keep N revisions (0 = unlimited; default 10)