nodejs-api

description	Generate Helm chart for Kubernetes application
shortcut	kh
category	devops
difficulty	advanced
estimated_time	3 minutes

Helm Chart Generator

Creates production-ready Helm charts for Kubernetes applications with parameterized templates, values files, and best practices.

When to Use This

• Package app for multiple environments (dev, staging, prod)
• Need configurable deployments (replicas, resources, ingress)
• Want version-controlled releases
• Deploy to multiple clusters with different configs
• Single environment deployment (use /k8s-manifest-generate)
• Quick one-off deployment (use kubectl run)

How It Works

You are a Helm expert. When user runs /k8s-helm-chart or /kh:

1. Detect application:

   • Identify workload type (Deployment, StatefulSet)
   • Determine configuration needs
   • Check for persistence requirements
   • Assess external access needs

2. Generate chart structure:

   mychart/
   ├── Chart.yaml           # Chart metadata
   ├── values.yaml          # Default values
   ├── values-dev.yaml      # Dev overrides
   ├── values-prod.yaml     # Production overrides
   ├── templates/
   │   ├── deployment.yaml  # Parameterized deployment
   │   ├── service.yaml     # Parameterized service
   │   ├── ingress.yaml     # Conditional ingress
   │   ├── configmap.yaml   # Configuration
   │   ├── secret.yaml      # Secrets (template only)
   │   ├── hpa.yaml         # Auto-scaling (conditional)
   │   └── _helpers.tpl     # Template helpers
   └── README.md            # Usage documentation
   

3. Parameterize templates:

   • Use Go templating ({{ .Values.* }})
   • Add conditionals for optional resources
   • Create reusable helpers
   • Apply naming conventions

4. Provide values files:

   • Sensible defaults in values.yaml
   • Environment-specific overrides
   • Comments explaining each value

5. Include deployment guide:

   • Installation commands
   • Upgrade procedures
   • Rollback instructions
   • Values customization guide

Output Format

# Complete chart directory structure
# Ready to use with helm install/upgrade

## Installation

### Install chart:
```bash
helm install myapp ./mychart -f values-prod.yaml

Upgrade:

helm upgrade myapp ./mychart -f values-prod.yaml

Rollback:

helm rollback myapp <revision>

## Example

**User:** `/kh` (for Node.js API)

**Questions:**
- App name? → `nodejs-api`
- Chart version? → `1.0.0`
- Default image? → `myregistry/nodejs-api:latest`
- Configurable options? → Replicas, resources, ingress, auto-scaling

**Output:**

```yaml
# Chart.yaml
apiVersion: v2
name: nodejs-api
description: Production-ready Node.js API Helm chart
type: application
version: 1.0.0
appVersion: "1.0.0"
keywords:
  - nodejs
  - api
  - microservice
maintainers:
  - name: Your Name
    email: [email protected]

# values.yaml
# Default values for nodejs-api chart

# Docker image configuration
image:
  repository: myregistry/nodejs-api
  pullPolicy: IfNotPresent
  tag: "latest"  # Override this in production!

# Number of replicas
replicaCount: 3

# Resource limits and requests
resources:
  requests:
    cpu: 250m
    memory: 512Mi
  limits:
    cpu: 500m
    memory: 1Gi

# Horizontal Pod Autoscaler (HPA)
autoscaling:
  enabled: true
  minReplicas: 2
  maxReplicas: 10
  targetCPUUtilizationPercentage: 70
  targetMemoryUtilizationPercentage: 80

# Service configuration
service:
  type: ClusterIP
  port: 80
  targetPort: 3000

# Ingress configuration
ingress:
  enabled: true
  className: nginx
  annotations:
     
  
      
      
          
           
  
      
      
         



   
   
   



     
       
          



  
     
     
     
  
     
     
     



   
   
   


 {}


 {}


 []


 {}

# values-dev.yaml
# Development environment overrides

replicaCount: 1

autoscaling:
  enabled: false

image:
  tag: "dev"

resources:
  requests:
    cpu: 100m
    memory: 256Mi
  limits:
    cpu: 250m
    memory: 512Mi

ingress:
  enabled: true
  hosts:
    - host: api-dev.example.com
      paths:
        - path: /
          pathType: Prefix

config:
  NODE_ENV: "development"
  LOG_LEVEL: "debug"

# values-prod.yaml
# Production environment overrides

replicaCount: 5

image:
  tag: "1.0.0"  # Specific version, not 'latest'

autoscaling:
  enabled: true
  minReplicas: 3
  maxReplicas: 20

resources:
  requests:
    cpu: 500m
    memory: 1Gi
  limits:
    cpu: 1000m
    memory: 2Gi

ingress:
  enabled: true
  annotations:
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
    nginx.ingress.kubernetes.io/rate-limit: "100"
  hosts:
    - host: api.example.com
      paths:
        - path: /
          pathType: Prefix

config:
  NODE_ENV: "production"
  LOG_LEVEL: "info"

# Pod disruption budget for high availability
podDisruptionBudget:
  enabled: true
  minAvailable: 

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "nodejs-api.fullname" . }}
  labels:
    {{- include "nodejs-api.labels" . | nindent 4 }}
spec:
  {{- if not .Values.autoscaling.enabled }}
  replicas: {{ .Values.replicaCount }}
  {{- end }}
  selector:
    matchLabels:
      {{- include "nodejs-api.selectorLabels" . | nindent 6 }}
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  template:
    metadata:
      annotations:
        checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . |  }}
        {{   }}
        {{      }}
        {{  }}
      
        {{       }}
    
      
        {{      }}
      
        {{  }}
         
         {{  }}
        
          
           {{  }}
           
        
         
             {{    }}
         
             {{    }}
        
          {{      }}
        
          
             {{  }}
             
           {{  }}
           {{  }}
        
          
             {{  }}
             
           {{  }}
           {{  }}
      {{   }}
      
        {{      }}
      {{  }}
      {{   }}
      
        {{      }}
      {{  }}
      {{   }}
      
        {{      }}
      {{  }}

# templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: {{ include "nodejs-api.fullname" . }}
  labels:
    {{- include "nodejs-api.labels" . | nindent 4 }}
spec:
  type: {{ .Values.service.type }}
  ports:
    - port: {{ .Values.service.port }}
      targetPort: http
      protocol: TCP
      name: http
  selector:
    {{- include "nodejs-api.selectorLabels" . | nindent 4 }}

# templates/ingress.yaml
{{- if .Values.ingress.enabled -}}
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: {{ include "nodejs-api.fullname" . }}
  labels:
    {{- include "nodejs-api.labels" . | nindent 4 }}
  {{- with .Values.ingress.annotations }}
  annotations:
    {{- toYaml . | nindent 4 }}
  {{- end }}
spec:
  ingressClassName: {{ .Values.ingress.className }}
  {{- if .Values.ingress.tls }}
  tls:
    {{- range .Values.ingress.tls }}
    - hosts:
        {{- range .hosts }}
        - {{ . | quote }}
        {{- end }}
      secretName: {{  }}
    {{  }}
  {{  }}
  
    {{   }}
      {{    }}
      
        
          {{   }}
            {{  }}
             {{  }}
            
              
                 {{    }}
                
                   {{  }}
          {{  }}
    {{  }}
{{  }}

# templates/hpa.yaml
{{- if .Values.autoscaling.enabled }}
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: {{ include "nodejs-api.fullname" . }}
  labels:
    {{- include "nodejs-api.labels" . | nindent 4 }}
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: {{ include "nodejs-api.fullname" . }}
  minReplicas: {{ .Values.autoscaling.minReplicas }}
  maxReplicas: {{ .Values.autoscaling.maxReplicas }}
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
  - type: Resource
    resource:
      name: memory
      
         
         {{  }}
{{  }}

{{/* templates/_helpers.tpl */}}

{{/*
Expand the name of the chart.
*/}}
{{- define "nodejs-api.name" -}}
{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
{{- end }}

{{/*
Create a default fully qualified app name.
*/}}
{{- define "nodejs-api.fullname" -}}
{{- if .Values.fullnameOverride }}
{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- $name := default .Chart.Name .Values.nameOverride }}
{{- if contains $name .Release.Name }}
{{- .Release.Name | trunc 63 | trimSuffix "-" }}
{{- else }}
{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
{{- end }}
{{- end }}
{{- end }}

{{/*
Create chart name and version as used by the chart label.
*/}}
{{- define "nodejs-api.chart" -}}
{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" }}
{{- end }}

{{/*
Common labels
*/}}
{{- define "nodejs-api.labels" -}}
helm.sh/chart: {{ include "nodejs-api.chart" . }}
{{ include "nodejs-api.selectorLabels" . }}
{{- if .Chart.AppVersion }}
app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
{{- end }}
app.kubernetes.io/managed-by: {{ .Release.Service }}
{{- end }}

{{/*
Selector labels
*/}}
{{- define "nodejs-api.selectorLabels" -}}
app.kubernetes.io/name: {{ include "nodejs-api.name" . }}
app.kubernetes.io/instance: {{ .Release.Name }}
{{- end }}

Deployment Guide:

# Helm Chart Usage

## Installation

### Development:
```bash
helm install nodejs-api ./nodejs-api -f values-dev.yaml

Production:

# Set secrets via command line (more secure)
helm install nodejs-api ./nodejs-api \
  -f values-prod.yaml \
  --set secrets.DATABASE_URL="postgresql://..." \
  --set secrets.JWT_SECRET="..." \
  --set secrets.API_KEY="..."

Upgrade

helm upgrade nodejs-api ./nodejs-api -f values-prod.yaml

Rollback

# List revisions
helm history nodejs-api

# Rollback to previous
helm rollback nodejs-api

# Rollback to specific revision
helm rollback nodejs-api 3

Verify Installation

helm list
helm status nodejs-api
kubectl get pods -l app.kubernetes.io/name=nodejs-api

Uninstall

helm uninstall nodejs-api

Pro Tips

Use values files for environments (values-{env}.yaml) Set secrets via --set (don't commit them) Pin image tags in production (not 'latest') Test with: helm template nodejs-api ./nodejs-api -f values-prod.yaml Validate with: helm lint ./nodejs-api