Helm Values

Managing values files and configuration overrides in Helm.

Values Hierarchy

Helm merges values from multiple sources (lower precedence first):

• Built-in default values

• Chart's values.yaml

• Parent chart's values

• Values files specified with -f (can be multiple)

• Individual parameters with --set

values.yaml Structure

Organize by Resource

Global settings

global: environment: production domain: example.com

Application settings

app: name: myapp version: "1.0.0"

Image settings

image: repository: myregistry/myapp pullPolicy: IfNotPresent tag: "" # Overrides appVersion

Service settings

service: type: ClusterIP port: 80 targetPort: 8080

Ingress settings

ingress: enabled: false className: nginx annotations: {} hosts: - host: myapp.example.com paths: - path: / pathType: Prefix tls: []

Resources

resources: limits: cpu: 500m memory: 512Mi requests: cpu: 250m memory: 256Mi

Persistence

persistence: enabled: false storageClass: "" accessMode: ReadWriteOnce size: 8Gi

Override Strategies

Override with File

Single file

helm install myrelease ./mychart -f custom-values.yaml

Multiple files (later files override earlier)

helm install myrelease ./mychart
-f values-base.yaml
-f values-production.yaml

Override with --set

Single value

helm install myrelease ./mychart --set image.tag=2.0.0

Multiple values

helm install myrelease ./mychart
--set image.tag=2.0.0
--set replicaCount=5

Nested values

helm install myrelease ./mychart
--set ingress.enabled=true
--set ingress.hosts[0].host=myapp.com

Override with --set-string

Force string type (useful for numeric-looking strings)

helm install myrelease ./mychart
--set-string version="1.0"

Override with --set-file

Read value from file

helm install myrelease ./mychart
--set-file config=./config.json

Environment-Specific Values

values-development.yaml

replicaCount: 1

image: tag: "dev-latest" pullPolicy: Always

resources: limits: cpu: 200m memory: 256Mi

ingress: enabled: true hosts: - host: dev.myapp.com

postgresql: enabled: true

values-production.yaml

replicaCount: 5

image: tag: "1.0.0" pullPolicy: IfNotPresent

resources: limits: cpu: 1000m memory: 1Gi

ingress: enabled: true hosts: - host: myapp.com tls: - secretName: myapp-tls hosts: - myapp.com

postgresql: enabled: false external: host: prod-db.example.com

Global Values

Parent Chart values.yaml

global: environment: production storageClass: fast-ssd

postgresql: auth: existingSecret: db-credentials

Subchart Access

In subchart template

environment: {{ .Values.global.environment }}

Schema Validation

values.schema.json

{ "$schema": "http://json-schema.org/draft-07/schema#", "type": "object", "required": ["image"], "properties": { "replicaCount": { "type": "integer", "minimum": 1, "maximum": 10 }, "image": { "type": "object", "required": ["repository"], "properties": { "repository": { "type": "string" }, "tag": { "type": "string" }, "pullPolicy": { "type": "string", "enum": ["Always", "IfNotPresent", "Never"] } } }, "service": { "type": "object", "properties": { "type": { "type": "string", "enum": ["ClusterIP", "NodePort", "LoadBalancer"] }, "port": { "type": "integer", "minimum": 1, "maximum": 65535 } } } } }

Secrets in Values

Don't Commit Secrets

values.yaml - public defaults

database: host: "" username: "" password: ""

values-secrets.yaml - not in git

database: host: "prod-db.example.com" username: "dbuser" password: "super-secret"

Use External Secrets

values.yaml

database: useExistingSecret: true existingSecretName: db-credentials

In template

{{- if .Values.database.useExistingSecret }} secretKeyRef: name: {{ .Values.database.existingSecretName }} key: password {{- else }} value: {{ .Values.database.password | quote }} {{- end }}

Complex Value Structures

Lists

values.yaml

extraEnvVars:

• name: LOG_LEVEL value: info
• name: API_KEY valueFrom: secretKeyRef: name: api-secret key: key

template

{{- range .Values.extraEnvVars }}

• name: {{ .name }} {{- if .value }} value: {{ .value | quote }} {{- else if .valueFrom }} valueFrom: {{- toYaml .valueFrom | nindent 4 }} {{- end }} {{- end }}

Maps

values.yaml

annotations: prometheus.io/scrape: "true" prometheus.io/port: "9090"

labels: team: platform environment: production

template

annotations: {{- range $key, $value := .Values.annotations }} {{ $key }}: {{ $value | quote }} {{- end }}

Best Practices

Document Values

values.yaml with comments

Number of replicas

@param replicaCount - Number of pod replicas

replicaCount: 3

Image configuration

@param image.repository - Docker image repository

@param image.tag - Docker image tag (defaults to Chart appVersion)

image: repository: myapp tag: ""

Sensible Defaults

Provide production-ready defaults

replicaCount: 3 # Not 1

resources: limits: cpu: 500m memory: 512Mi requests: cpu: 500m # Same as limit for guaranteed QoS memory: 512Mi

Feature Flags

Allow enabling/disabling features

features: metrics: enabled: true port: 9090

tracing: enabled: false endpoint: ""

View Computed Values

See final merged values

helm get values myrelease

See all values (including defaults)

helm get values myrelease --all

Template with values

helm template myrelease ./mychart -f custom-values.yaml