How to Manage Helm Chart Dependencies

Helm dependencies let you compose complex applications from reusable charts. Learn to declare, configure, and manage chart dependencies effectively.

Declaring Dependencies

# Chart.yaml
apiVersion: v2
name: myapp
version: 1.0.0
appVersion: "2.0.0"

dependencies:
  - name: postgresql
    version: "12.x.x"
    repository: "https://charts.bitnami.com/bitnami"
  - name: redis
    version: "17.x.x"
    repository: "https://charts.bitnami.com/bitnami"
  - name: common
    version: "2.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    tags:
      - backend

Building Dependencies

# Download dependencies to charts/ directory
helm dependency build

# Update dependencies (also downloads)
helm dependency update

# List dependencies
helm dependency list

Conditional Dependencies

# Chart.yaml
dependencies:
  - name: postgresql
    version: "12.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: postgresql.enabled
  - name: mysql
    version: "9.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    condition: mysql.enabled

# values.yaml
postgresql:
  enabled: true

mysql:
  enabled: false

Using Tags for Groups

# Chart.yaml
dependencies:
  - name: backend-api
    version: "1.0.0"
    repository: "file://../backend-api"
    tags:
      - backend
  - name: worker
    version: "1.0.0"
    repository: "file://../worker"
    tags:
      - backend
  - name: frontend
    version: "1.0.0"
    repository: "file://../frontend"
    tags:
      - frontend

# values.yaml
publishDate: "2026-01-22"
tags:
  backend: true
  frontend: true

# Install only backend components
helm install myapp . --set tags.frontend=false

Overriding Subchart Values

# values.yaml - Override postgresql subchart values
postgresql:
  enabled: true
  auth:
    postgresPassword: "secretpassword"
    database: "myapp"
  primary:
    persistence:
      size: 20Gi
    resources:
      requests:
        memory: 256Mi
        cpu: 100m
      limits:
        memory: 512Mi
        cpu: 500m

redis:
  enabled: true
  architecture: standalone
  auth:
    enabled: true
    password: "redispassword"
  master:
    persistence:
      size: 5Gi

Importing Values from Subcharts

# Chart.yaml
dependencies:
  - name: postgresql
    version: "12.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    import-values:
      - child: primary.service
        parent: database

# Now in templates, use .Values.database.port instead of
# .Values.postgresql.primary.service.port

Alias for Multiple Instances

# Chart.yaml
dependencies:
  - name: redis
    version: "17.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    alias: redis-cache
  - name: redis
    version: "17.x.x"
    repository: "https://charts.bitnami.com/bitnami"
    alias: redis-session

# values.yaml
redis-cache:
  architecture: standalone
  master:
    persistence:
      size: 2Gi

redis-session:
  architecture: standalone
  master:
    persistence:
      size: 1Gi

Local Chart Dependencies

# Chart.yaml - Reference local charts
dependencies:
  - name: shared-lib
    version: "1.0.0"
    repository: "file://../shared-lib"
  - name: auth-service
    version: "2.0.0"
    repository: "file://./charts/auth-service"

OCI Registry Dependencies

# Chart.yaml - Using OCI registries
dependencies:
  - name: mylib
    version: "1.0.0"
    repository: "oci://registry.example.com/charts"

# Login to OCI registry first
helm registry login registry.example.com

Global Values

# values.yaml - Global values available to all subcharts
global:
  imageRegistry: "registry.example.com"
  imagePullSecrets:
    - name: registry-secret
  storageClass: "fast-ssd"

# Subcharts can access via .Values.global.imageRegistry

Template Usage with Dependencies

# templates/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ .Release.Name }}-config
data:
  # Reference subchart service names
  DATABASE_HOST: {{ .Release.Name }}-postgresql
  DATABASE_PORT: "5432"
  DATABASE_NAME: {{ .Values.postgresql.auth.database }}
  REDIS_HOST: {{ .Release.Name }}-redis-master
  REDIS_PORT: "6379"

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}-app
spec:
  template:
    spec:
      containers:
        - name: app
          env:
            - name: DATABASE_URL
              value: "postgres://{{ .Values.postgresql.auth.database }}:$(DB_PASSWORD)@{{ .Release.Name }}-postgresql:5432/{{ .Values.postgresql.auth.database }}"
            - name: DB_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: {{ .Release.Name }}-postgresql
                  key: postgres-password

Wait for Dependencies

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}-app
spec:
  template:
    spec:
      initContainers:
        - name: wait-for-db
          image: busybox:latest
          command:
            - /bin/sh
            - -c
            - |
              until nc -z {{ .Release.Name }}-postgresql 5432; do
                echo "Waiting for PostgreSQL..."
                sleep 2
              done
              echo "PostgreSQL is ready!"
        - name: wait-for-redis
          image: busybox:latest
          command:
            - /bin/sh
            - -c
            - |
              until nc -z {{ .Release.Name }}-redis-master 6379; do
                echo "Waiting for Redis..."
                sleep 2
              done
              echo "Redis is ready!"
      containers:
        - name: app
          image: {{ .Values.image.repository }}:{{ .Values.image.tag }}

Dependency Lock File

# Chart.lock - Auto-generated, commit to version control
dependencies:
- name: postgresql
  repository: https://charts.bitnami.com/bitnami
  version: 12.5.6
- name: redis
  repository: https://charts.bitnami.com/bitnami
  version: 17.11.3
digest: sha256:abc123...
generated: "2024-01-15T10:30:00Z"

# Rebuild from lock file (reproducible builds)
helm dependency build

Summary

Helm dependencies enable modular, reusable chart composition. Use conditions and tags for flexibility, override values for customization, and leverage global values for consistency across subcharts.

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