helm --set, --set-string and -f: override chart values

updated 2026-10-20

tool: Helm
command: helm install / helm upgrade / helm template
flag: --set
default: values from values.yaml

--set key=value overrides a value from the chart's values.yaml for one release. Dots address nested keys (image.tag=1.29.0), braces build lists (list={a,b,c}), and commas separate several assignments. Helm guesses the type: true becomes a boolean and 3 an integer, which --set-string prevents.

See how values are typed

bash

helm create mychart >/dev/null
cat > mychart/templates/cm.yaml <<'EOF'
apiVersion: v1
kind: ConfigMap
metadata:
  name: cfg
data:
  flag: {{ kindOf .Values.flag | quote }}
  num: {{ kindOf .Values.num | quote }}
  list: {{ .Values.list | join "," | quote }}
  host: {{ .Values.ingress.host | quote }}
EOF
helm template demo ./mychart --show-only templates/cm.yaml \
  --set flag=true --set num=3 --set 'list={a,b,c}' --set ingress.host=app.example.com
helm template demo ./mychart --show-only templates/cm.yaml --set-string flag=true --set num=3 \
  --set 'list={a}' --set ingress.host=x | grep flag

Output

---
# Source: mychart/templates/cm.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: cfg
data:
  flag: "bool"
  num: "int64"
  list: "a,b,c"
  host: "app.example.com"

  flag: "string"

Precedence

Later sources win: chart values.yaml, then each -f file in order, then --set/--set-string/--set-file in order.

bash

helm upgrade --install web ./mychart -f values.prod.yaml --set image.tag=1.29.0

Syntax

Flag	Example	Result
--set	replicaCount=3	replicaCount: 3 (int)
--set	image.tag=1.29.0	image: {tag: "1.29.0"}
--set	'list={a,b,c}'	list: [a, b, c]
--set	servers[0].port=80	first list item, key port
--set	name=a\,b	a literal comma: name: "a,b"
--set-string	flag=true	flag: "true" (string)
--set-file	config=./app.conf	value read from a file
-f / --values	values.prod.yaml	a whole values file

Sources

errors · helmHelm: nil pointer evaluating interface {}.valuehelm template and helm install fail with nil pointer evaluating interface {} when a template reads a nested value whose parent key is missing from values.yaml.commands · kubernetesGenerate Kubernetes YAML with kubectl create --dry-run=client -o yamlkubectl create deployment, service, configmap or secret with --dry-run=client -o yaml prints a ready manifest without a cluster. Save it with > file.yaml.cheat sheets · kuberneteskubectl cheat sheet: everyday Kubernetes commandskubectl cheat sheet: contexts and namespaces, get and describe, logs and exec, apply and rollout, port-forward, scaling, and manifests with --dry-run=client.

See how values are typed

Precedence

Syntax

Sources

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