Helm - Parser Full Documentation

The parser for Helm translates Docker configurations into Kubernetes Helm Charts. The parser logic can be found in GitHub inside the docker-to-iac repo.

Parser language abbreviation for API

• languageAbbreviation: HELM.

Prerequisite to deploy Helm Charts

To deploy the generated Helm Charts, you need:

• A Kubernetes cluster (local or cloud-based)
• Helm CLI installed (version 3.x recommended)
• Appropriate RBAC permissions to deploy resources in your target namespace

Kubernetes Resources

The generated Helm Chart creates the following Kubernetes resources for each service in your Docker configuration:

• Deployments: Container specifications, replica count, resource limits
• Services: Network access to your pods with appropriate ports
• ConfigMaps: Non-sensitive environment variables
• Secrets: Sensitive environment variables (passwords, tokens, etc.)

Database Support

For database services, the parser leverages Helm's dependency management to incorporate official Bitnami charts:

• MySQL/MariaDB: Uses Bitnami's MySQL/MariaDB chart
• PostgreSQL: Uses Bitnami's PostgreSQL chart
• Redis: Uses Bitnami's Redis chart
• MongoDB: Uses Bitnami's MongoDB chart

Each database dependency is configured with appropriate defaults and includes persistent storage for data.

Default output format

• The default output format for this parser: YAML.

File Configuration

The Helm parser generates a complete Helm Chart directory structure:

• Chart.yaml - The main chart definition with metadata and dependencies
• values.yaml - Configuration values that can be customized at deployment time
• templates/ - Directory containing Kubernetes YAML templates:
  • deployment.yaml - Deployment specifications for each service
  • service.yaml - Service definitions for network access
  • configmap.yaml - ConfigMap for non-sensitive environment variables
  • secret.yaml - Secret for sensitive environment variables
  • _helpers.tpl - Helper functions for template generation
  • NOTES.txt - Usage instructions displayed after installation

This multi-file approach follows the standard Helm Chart structure and allows for maximum flexibility when deploying to Kubernetes.

Supported Docker Compose Variables

This parser supports the following Docker Compose variables:

• image
• environment
• ports
• command
• volumes

Volume Support

The parser supports Docker volume mappings by converting them to Kubernetes volume mounts:

• Each volume is converted to a hostPath volume by default
• Volume names are sanitized to conform to Kubernetes naming conventions
• For production use, you should modify the generated templates to use more appropriate volume types (PersistentVolumeClaims, etc.)

Database Integration

When a database service is detected (MySQL, PostgreSQL, Redis, MongoDB), the parser:

1. Adds the corresponding Bitnami Helm chart as a dependency in Chart.yaml
2. Configures database settings in values.yaml
3. Maps environment variables to the expected format for the database chart
4. Sets up appropriate persistence configurations

Example Database Configuration

For a PostgreSQL database in your Docker Compose file:

services:
  db:
    image: postgres:13
    environment:
      POSTGRES_USER: myuser
      POSTGRES_PASSWORD: mypassword
      POSTGRES_DB: myapp

The parser will create:

# In Chart.yaml
dependencies:
  - name: db
    repository: https://charts.bitnami.com/bitnami
    version: ^12.0.0
    condition: dependencies.db.enabled

# In values.yaml
dependencies:
  db:
    enabled: true
    auth:
      postgres:
        password: mypassword
      database: myapp
      username: myuser
      password: mypassword
    primary:
      service:
        ports:
          postgresql: 5432
      persistence:
        enabled: true
        size: 8Gi

Service Connections

The parser supports service-to-service connections by leveraging Kubernetes DNS for service discovery. When a service refers to another service in an environment variable, the parser automatically configures the appropriate DNS references.

For example, if your app service connects to a db service:

# Docker Compose
services:
  app:
    image: myapp
    environment:
      DATABASE_URL: postgresql://postgres:password@db:5432/mydb
  
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mydb

The parser will create:

# In ConfigMap template
data:
  DATABASE_URL: {{ include "deploystack.serviceReference" (dict "service" (index $.Values.services "db") "serviceKey" "db") }}

Which resolves to the Kubernetes DNS name: db.{{ .Release.Namespace }}.svc.cluster.local:5432

Multi Services Support

Multi services support for Helm: yes

Helm Charts are designed to handle multiple services and dependencies in a single deployment, making them ideal for complex applications. The parser transforms all services from your Docker Compose file into corresponding Kubernetes resources.

Please read more about multi service support here.

Deployment Instructions

To deploy the generated Helm Chart:

1. Navigate to the directory containing the generated chart

2. Install dependencies:

   helm dependency update

3. Install the chart:

   helm install my-release .

4. For custom configurations:

   helm install my-release . --set services.app.replicaCount=2

Production Considerations

For production deployments, consider the following modifications to the generated chart:

1. Replace hostPath volumes with appropriate persistent volume claims
2. Adjust resource limits in values.yaml
3. Configure proper ingress settings for external access
4. Enable and configure horizontal pod autoscaling
5. Set up proper liveness and readiness probes