Values Management

values.yaml Overrides Environment-Specific Values Schema Validation

A comprehensive guide to Helm values management covering values.yaml, overrides, environment-specific values, schema validation, and best practices for configuration management.

values.yaml Overrides Environment Values Schema Validation

What are Helm Values?

Helm values are the configuration parameters that customize chart behavior. They allow you to adapt a chart for different environments, use cases, and requirements without modifying the chart itself.

Values flow into templates and determine the final Kubernetes manifests. They are defined in:

values.yaml - Default values in the chart
--set - Command-line overrides
-f - External values files
--values - Multiple values files (merged in order)
Subchart values - Passed from parent to dependencies

Key Concept: Values are the primary interface between chart authors and chart users. Well-designed values make charts flexible, reusable, and easy to configure.

values.yaml: Default Configuration

values.yaml contains the default values for a chart. It serves as documentation and provides sensible defaults.

                # values.yaml - Example with structure

# Global settings
global:
  imagePullSecrets: []
  storageClass: standard
  registry: docker.io

# Application settings
replicaCount: 3
image:
  repository: nginx
  tag: latest
  pullPolicy: IfNotPresent
  pullSecrets: []

# Name overrides
nameOverride: ""
fullnameOverride: ""

# Service configuration
service:
  type: ClusterIP
  port: 80
  targetPort: 8080
  annotations: {}

# Ingress configuration
ingress:
  enabled: false
  className: ""
  annotations: {}
  hosts:
    - host: app.example.com
      paths:
        - path: /
          pathType: Prefix
  tls: []

# Resources
resources:
  requests:
    memory: "64Mi"
    cpu: "250m"
  limits:
    memory: "128Mi"
    cpu: "500m"

# Autoscaling
autoscaling:
  enabled: false
  minReplicas: 1
  maxReplicas: 10
  targetCPUUtilizationPercentage: 80

# Environment
environment: production

# ConfigMap data
configMap:
  key1: value1
  key2: value2

# Pod settings
podAnnotations: {}
podSecurityContext: {}
securityContext: {}

# Node selector and tolerations
nodeSelector: {}
tolerations: []
affinity: {}

# Persistence
persistence:
  enabled: false
  storageClass: ""
  accessMode: ReadWriteOnce
  size: 1Gi

# Extra resources
extraVolumes: []
extraVolumeMounts: []
extraEnv: []
            

values.yaml Best Practices:

Organize values logically with clear sections
Use descriptive keys and comments
Set sensible defaults for all configurable options
Document all values in README.md
Use global for shared configuration
Never store secrets in values.yaml

Values Overrides

Values can be overridden at installation or upgrade time using multiple methods.

                # Method 1: --set flag (single value)
helm install my-release ./my-chart --set replicaCount=5 --set image.tag=1.25

# Method 2: --set-string (force string)
helm install my-release ./my-chart --set-string service.type=ClusterIP

# Method 3: --set-file (load from file)
helm install my-release ./my-chart --set-file config=config.json

# Method 4: -f (values file)
helm install my-release ./my-chart -f custom-values.yaml

# Method 5: --values (multiple files, merged in order)
helm install my-release ./my-chart \
  --values base-values.yaml \
  --values env-values.yaml \
  --values secret-values.yaml

# Method 6: --set with JSON/YAML
helm install my-release ./my-chart \
  --set 'resources={"requests":{"memory":"128Mi"}}'

# Method 7: --set with nested values
helm install my-release ./my-chart \
  --set ingress.enabled=true \
  --set ingress.hosts[0].host=app.example.com

# Method 8: Using environment variables
export HELM_VALUES_REPLICAS=5
helm install my-release ./my-chart \
  --set replicaCount=$HELM_VALUES_REPLICAS

# Upgrade with new values
helm upgrade my-release ./my-chart -f production-values.yaml
            

--set

Override individual values from the command line. Good for quick changes and CI/CD.

-f / --values

Use external values files. Best for environment-specific configurations.

Multiple Files

Merge multiple values files (later files override earlier ones).

--set-string

Force values to be strings (useful for boolean-like strings).

Override Priority (highest to lowest):

Command-line --set
--values files (last file has highest priority)
values.yaml from the chart

Environment-Specific Values

Use different values files for different environments (dev, staging, production).

                # values-dev.yaml (Development)
replicaCount: 1
image:
  tag: dev
environment: development
ingress:
  enabled: true
  hosts:
    - host: dev.example.com
resources:
  requests:
    memory: "64Mi"
    cpu: "100m"

# values-staging.yaml (Staging)
replicaCount: 2
image:
  tag: staging
environment: staging
ingress:
  enabled: true
  hosts:
    - host: staging.example.com
resources:
  requests:
    memory: "128Mi"
    cpu: "250m"

# values-prod.yaml (Production)
replicaCount: 5
image:
  tag: latest
environment: production
ingress:
  enabled: true
  annotations:
    kubernetes.io/ingress.class: nginx
    cert-manager.io/cluster-issuer: letsencrypt-prod
  hosts:
    - host: app.example.com
  tls:
    - hosts:
        - app.example.com
      secretName: app-tls
resources:
  requests:
    memory: "256Mi"
    cpu: "500m"
  limits:
    memory: "512Mi"
    cpu: "1000m"
autoscaling:
  enabled: true
  minReplicas: 3
  maxReplicas: 10

# Install with environment files
helm install my-release ./my-chart -f values-dev.yaml
helm upgrade my-release ./my-chart -f values-staging.yaml
helm upgrade my-release ./my-chart -f values-prod.yaml

# Combine base + environment values
helm install my-release ./my-chart \
  -f values-base.yaml \
  -f values-dev.yaml
            

Environment Values Best Practices:

Maintain separate values files for each environment
Use a base values file for common settings
Keep environment-specific overrides minimal
Don't store secrets in environment values files
Use CI/CD to apply the correct values file
Document all environment-specific overrides

Values Schema Validation

values.schema.json provides JSON Schema validation for values.yaml, catching misconfigurations before installation.

                # values.schema.json
{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "replicaCount": {
      "type": "integer",
      "minimum": 1,
      "maximum": 10,
      "description": "Number of replicas for the deployment"
    },
    "image": {
      "type": "object",
      "properties": {
        "repository": {
          "type": "string",
          "description": "Container image repository"
        },
        "tag": {
          "type": "string",
          "default": "latest",
          "description": "Container image tag"
        },
        "pullPolicy": {
          "type": "string",
          "enum": ["Always", "IfNotPresent", "Never"],
          "default": "IfNotPresent"
        }
      },
      "required": ["repository"]
    },
    "service": {
      "type": "object",
      "properties": {
        "type": {
          "type": "string",
          "enum": ["ClusterIP", "NodePort", "LoadBalancer"],
          "default": "ClusterIP"
        },
        "port": {
          "type": "integer",
          "minimum": 1,
          "maximum": 65535,
          "description": "Service port"
        }
      },
      "required": ["port"]
    },
    "ingress": {
      "type": "object",
      "properties": {
        "enabled": {
          "type": "boolean",
          "default": false
        },
        "hosts": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "host": {
                "type": "string",
                "format": "hostname"
              }
            },
            "required": ["host"]
          }
        }
      }
    },
    "resources": {
      "type": "object",
      "properties": {
        "requests": {
          "type": "object",
          "properties": {
            "memory": {
              "type": "string",
              "pattern": "^[0-9]+(Mi|Gi|M|G)$"
            },
            "cpu": {
              "type": "string",
              "pattern": "^[0-9]+(m)?$"
            }
          }
        },
        "limits": {
          "type": "object",
          "properties": {
            "memory": {
              "type": "string",
              "pattern": "^[0-9]+(Mi|Gi|M|G)$"
            },
            "cpu": {
              "type": "string",
              "pattern": "^[0-9]+(m)?$"
            }
          }
        }
      }
    }
  },
  "required": ["image"]
}
            

Schema Validation Benefits:

Prevents invalid configurations
Provides better error messages
Documents expected values
Enforces type safety
Improves developer experience

Global Values

Global values are accessible from all subcharts. They're defined in the global section of values.yaml.

                # Parent chart values.yaml
global:
  storageClass: standard
  imagePullSecrets:
    - name: regcred
  registry: docker.io
  environment: production

# Subchart uses global values
# In subchart templates
{{ .Values.global.storageClass }}
{{ .Values.global.registry }}/{{ .Values.image.repository }}

# Override global values
helm install my-release ./my-chart \
  --set global.storageClass=ssd \
  --set global.environment=staging

# Subchart can also have its own values
# Subchart values.yaml
image:
  repository: myapp
  tag: latest

# Combined with global values
# Final image: {{ .Values.global.registry }}/{{ .Values.image.repository }}:{{ .Values.image.tag }}
            

Global Values Best Practices:

Use global values for shared configuration
Document global values clearly
Keep global values minimal
Use global for registry, storage class, image pull secrets
Override global values at the parent level

Frequently Asked Questions

What is the difference between values.yaml and values.schema.json?

values.yaml contains default values. values.schema.json provides JSON Schema validation for values, ensuring they meet the expected format and constraints.

How do I override values in a subchart?

Use the subchart name as a key in the parent values. Example: postgresql: {postgresqlPassword: secret} overrides values for the postgresql subchart.

What is the priority order for values?

From highest to lowest: --set > --values files (later files override earlier) > values.yaml in the chart > default values.

How do I pass secrets as values?

Use --set with sensitive values, or use external secret management tools. Never store secrets in values.yaml files. Use --set or environment variables in CI/CD.

What are global values?

Global values are defined in the global section of values.yaml and are accessible from all subcharts. They're used for shared configuration like registry, storage class, and image pull secrets.

How do I validate values before installation?

Use values.schema.json for JSON Schema validation. You can also use helm template --dry-run to test values and see the rendered output.

Can I use environment variables in values files?

Helm doesn't directly support environment variables in values files. Use --set with environment variables or use a templating tool like envsubst before passing to Helm.

How do I view the final values used by a release?

Use helm get values <release> to see the values for an installed release. Use helm get values --all to see all values including defaults.

Values Management

--set

-f / --values

Multiple Files

--set-string

What is Helm?

Chart Structure

Helm Templating

Template Helpers

Sprig Functions

Helm Best Practices