Working with Values Files

1. Creating values.yaml Default Values

Property	Default Value	Description
replicaCount	`1`	Number of replicas for the deployment
image.repository	`nginx`	Container image repository name
image.tag	`latest`	Container image tag
service.type	`ClusterIP`	Kubernetes service type to expose the application
service.port	`80`	Port to expose the service on
resources.limits.cpu	`500m`	CPU limit for the container
resources.limits.memory	`512Mi`	Memory limit for the container

Example: Default values.yaml

replicaCount: 1
image:
  repository: nginx
  tag: latest
service:
  type: ClusterIP
  port: 80
resources:
  limits:
    cpu: 500m
    memory: 512Mi

2. Understanding Values Hierarchy

Level	File	Description
1	`values.yaml`	Default values provided by the chart author
2	`values.yaml` in chart	Override values within the chart's own `values.yaml`
3	`values.yaml` from `--set`	Command-line overrides using `--set` flag
4	`values.yaml` from `--set-string`	Command-line overrides for string values using `--set-string`
5	`values.yaml` from `--set-file`	Command-line overrides using file content with `--set-file`
6	`values.yaml` from `-f`	Override values using additional `-f` files (e.g., `-f prod.yaml`)
7	`values.yaml` from `--values`	Override values using additional `--values` files (e.g., `--values staging.yaml`)

Example: Values Hierarchy in Action

# Default values from chart
replicaCount: 1
image:
  repository: nginx
  tag: "latest"
  pullPolicy: IfNotPresent

# Override in --set
--set image.tag="v1.23"

# Override via -f prod.yaml
image:
  tag: "production-v1"

Note: The order of precedence is defined in the Helm documentation. Values from --set and -f files override default values in the chart.

3. Using Custom Values Files

Property	Values	Description
values.yaml	`config: { port: 8080 }`	Default values file for chart configuration
--set	`key=value`	Override values from command line
--values	`custom-values.yaml`	Specify custom values file path

Example: Using custom values file

helm install my-app ./my-chart --values custom-values.yaml

Example: Overriding with --set

helm install my-app ./my-chart --set config.port=9000

4. Setting Individual Values

Property	Value	Description
helm install --set key1=value1,key2=value2	`helm install my-release my-chart --set database.port=5432,database.username=admin`	Set individual values during installation using comma-separated key-value pairs
helm upgrade --set key1=value1	`helm upgrade my-release my-chart --set image.tag=v2.0`	Update a release with new individual values
helm template --set key1=value1	`helm template my-release my-chart --set service.type=LoadBalancer`	Render templates with individual values without installing

Example: Setting a nested value

helm install my-app stable/nginx --set service.port=8080

Example: Setting multiple values at once

helm install my-app stable/nginx --set image.tag=v2.0,image.pullPolicy=Always

5. Using String Values

Property	Value Type	Description
app.name	`string`	Name of the application
app.version	`string`	Version of the application
app.image	`string`	Docker image name and tag

Example: Setting String Values

app:
  name: "my-app"
  version: "1.0.0"
  image: "nginx:latest"

6. Setting File Content Values

Property	Values	Description
configMap.data	`string`	Data to be stored in the ConfigMap
configMap.binaryData	`string`	Binary data to be stored in the ConfigMap
secret.data	`string`	Data to be stored in the Secret
secret.stringData	`string`	Unencoded string data to be stored in the Secret

Example: Setting File Content in ConfigMap

configMap:
  name: "app-config"
  data:
    app.properties: |
      server.port=8080
      logging.level=INFO

Example: Setting File Content in Secret

secret:
  name: "app-secret"
  stringData:
    database.password: "secret123"

7. Setting JSON Values

Property	Value	Description
jsonValue	`{"key": "value"}`	Direct JSON object value
nested.json.key	`"string"`	String value within nested JSON structure

Example: Setting JSON Values in Values File

jsonValue:
  key: value
nested:
  json:
    key: "string"

Note: JSON values in Helm are handled as YAML, so nested structures can be defined using standard YAML syntax.

8. Merging Multiple Values Files

Example: Merging values files

# values-dev.yaml
replicaCount: 2
image:
  repository: nginx
  tag: "1.21"
service:
  type: ClusterIP
  port: 80

# values-prod.yaml
replicaCount: 10
image:
  tag: "1.22"
service:
  type: LoadBalancer
  port: 8080
  nodePort: 30080

# Merged result (prod overrides dev)
replicaCount: 10
image:
  repository: nginx
  tag: "1.22"
service:
  type: LoadBalancer
  port: 8080
  nodePort: 30080

File	Merge Priority	Description
values.yaml	`lowest`	Default values file, merged first
values-<env>.yaml	`higher`	Environment-specific overrides
--set	`highest`	Command-line overrides (highest priority)

Note: Helm merges values files in the order they are specified, with later files taking precedence.

Workflow: Merging multiple values files

Define base values.yaml with default settings
Create environment-specific files like values-staging.yaml, values-prod.yaml
Use helm install --values values-prod.yaml to merge files
Override with --set key=value for last-minute changes

9. Creating Environment-Specific Values

Environment-specific values files allow you to customize Helm chart deployments for different environments like development, staging, and production.

File Name Pattern	Description	Usage
values-dev.yaml	Values for the development environment	Used with `helm install --values values-dev.yaml`
values-staging.yaml	Values for the staging environment	Used with `helm install --values values-staging.yaml`
values-prod.yaml	Values for the production environment	Used with `helm install --values values-prod.yaml`

Example: values-dev.yaml

replicaCount: 1
image:
  repository: myapp
  tag: "latest"
  pullPolicy: IfNotPresent
service:
  type: ClusterIP
  port: 80
resources:
  limits:
    cpu: 500m
    memory: 512Mi
  requests:
    cpu: 250m
    memory: 256Mi

Example: values-prod.yaml

replicaCount: 3
image:
  repository: myapp
  tag: "v1.2.3"
  pullPolicy: Always
service:
  type: LoadBalancer
  port: 80
resources:
  limits:
    cpu: 1000m
    memory: 1Gi
  requests:
    cpu: 500m
    memory: 512Mi

Note: Values files support YAML syntax and can be used to override any chart values. They are merged in order of precedence: default values < values file < --set overrides.

10. Documenting Values

Example: Using Comments in Values Files

# Helm Values File with Documentation
#
# Database Configuration
database:
  # The hostname of the database server
  host: "localhost"
  # The port to connect to the database
  port: 5432
  # The name of the database to connect to
  name: "myapp"
  # The username for database authentication
  username: "admin"
  # The password for database authentication (use secrets in production)
  password: "secret123"

# Service Configuration
service:
  # The port to expose the service on
  port: 8080
  # The type of service to create (ClusterIP, NodePort, etc.)
  type: "ClusterIP"

Field	Description	Type	Default Value
database.host	Hostname of the database server	string	`"localhost"`
database.port	Port to connect to the database	integer	`5432`
database.name	Name of the database to connect to	string	`"myapp"`
database.username	Username for database authentication	string	`"admin"`
database.password	Password for database authentication	string	`"secret123"`
service.port	Port to expose the service on	integer	`8080`
service.type	Type of service to create (e.g., ClusterIP, NodePort)	string	`"ClusterIP"`

Note: Comments in YAML files are not preserved when values are processed by Helm. For documentation purposes, consider using a separate README.md file or inline comments in templates.

11. Using Global Values

Property	Description	Usage
global.imageRegistry	Registry to use for all images in the chart	`global.imageRegistry: "my-registry.com"`
global.replicaCount	Number of replicas for all deployments	`global.replicaCount: 3`
global.storageClass	Storage class to use for persistent volumes	`global.storageClass: "fast"`

Example: Setting global values in values.yaml

global:
  imageRegistry: "my-registry.com"
  replicaCount: 3
  storageClass: "fast"

# Chart can reference these values using .Values.global.imageRegistry

Note: Global values are merged into the chart's values during template rendering and can be overridden at the chart level.