Helm Best Practices

Helm Best Practices

As you become proficient with Helm, it’s important to adopt best practices that ensure your Helm charts are maintainable, scalable, and secure. Following best practices not only helps you create high-quality charts but also simplifies collaboration, reduces the likelihood of errors, and makes it easier to manage deployments across different environments. In this lesson, we will cover a range of Helm best practices, from chart structure and versioning to security considerations and testing. By the end of this lesson, you’ll have a solid foundation for creating and maintaining Helm charts that adhere to industry standards.

Structuring Your Helm Charts

A well-structured Helm chart is easier to manage, understand, and extend. Following a consistent structure ensures that anyone who uses or maintains the chart can easily navigate and modify it.

Organizing Templates

Keep your templates organized and modular. Large, monolithic templates can be difficult to read and maintain. Instead, break down your templates into smaller, reusable components.

Best Practices for Organizing Templates:

• Use the _helpers.tpl File: Store common template logic and functions in the _helpers.tpl file. This reduces duplication and makes your templates more modular.

• Separate Concerns: Group related Kubernetes resources together in separate templates (e.g., deployment.yaml, service.yaml, configmap.yaml). This makes it easier to manage specific components of your chart.

Example of Using _helpers.tpl:

{{- define "myapp.labels" -}}
app: {{ include "myapp.name" . }}
{{- end -}}

metadata:
  labels:
    {{ include "myapp.labels" . }}

This approach centralizes label management, ensuring consistency across resources.

Consistent Naming Conventions

Use consistent naming conventions for your resources, values, and template functions. This improves readability and helps avoid conflicts, especially when integrating multiple charts.

Best Practices for Naming Conventions:

• Use Chart and Release Names: Incorporate the chart name and release name into resource names to avoid naming collisions.

• Use Lowercase and Hyphens: Stick to lowercase letters and hyphens for naming resources, as this is the standard in Kubernetes.

Example of Naming Resources:

yamlCopy codemetadata:
  name: {{ include "myapp.fullname" . }}

This ensures that the resource name includes both the release and chart name, preventing conflicts.

Versioning and Dependency Management

Versioning your charts correctly and managing dependencies effectively are critical for maintaining stability and compatibility across different environments.

Semantic Versioning

Follow semantic versioning (SemVer) for your Helm charts. This makes it clear when changes are backward-compatible, introduce new features, or break existing functionality.

Semantic Versioning Format:

• MAJOR.MINOR.PATCH

  • MAJOR: Incremented for incompatible API changes.

  • MINOR: Incremented for backward-compatible new features.

  • PATCH: Incremented for backward-compatible bug fixes.

Example of Versioning:

version: 1.2.0
appVersion: "2.3.4"

This versioning approach clearly communicates the level of changes between releases.

Managing Dependencies

If your chart relies on other charts, manage these dependencies carefully. Ensure that the versions of dependent charts are compatible with your chart.

Best Practices for Managing Dependencies:

• Use Specific Versions: Avoid using wildcard versions (e.g., * or ^). Specify exact versions of dependencies to ensure consistent deployments.

• Regularly Update Dependencies: Keep your dependencies up to date to benefit from bug fixes, security patches, and new features.

Example of Defining Dependencies in Chart.yaml:

yamlCopy codedependencies:
  - name: redis
    version: 6.0.8
    repository: https://charts.bitnami.com/bitnami

Specifying the exact version ensures that the chart always uses the same, tested version of Redis.

Security Best Practices

Security is a paramount concern when deploying applications in Kubernetes. Following security best practices in Helm helps protect your charts from vulnerabilities and misconfigurations.

Limiting Permissions

Ensure that your Helm charts do not grant unnecessary permissions to the resources they create. Follow the principle of least privilege, granting only the permissions required for the application to function.

Best Practices for Limiting Permissions:

• Use Minimal Service Accounts: Define service accounts with minimal permissions.

• Avoid Cluster-Wide Permissions: Where possible, avoid using cluster-wide roles and resources like ClusterRole and ClusterRoleBinding.

Example of a Minimal Service Account:

yamlCopy codeapiVersion: v1
kind: ServiceAccount
metadata:
  name: {{ include "myapp.fullname" . }}
  namespace: {{ .Release.Namespace }}

This service account is namespace-bound and does not have any unnecessary permissions.

Securing Sensitive Data

Handle sensitive data such as passwords, API keys, and certificates securely. Avoid hardcoding sensitive data directly in your charts.

Best Practices for Securing Sensitive Data:

• Use Kubernetes Secrets: Store sensitive information in Kubernetes Secrets.

• Support External Secrets: Allow your chart to reference externally managed secrets instead of embedding them in values.yaml.

Example of Using a Kubernetes Secret:

apiVersion: v1
kind: Secret
metadata:
  name: {{ include "myapp.fullname" . }}-secret
type: Opaque
data:
  password: {{ .Values.password | b64enc | quote }}

This approach stores sensitive information securely in a Kubernetes Secret.

Testing and Validation

Thoroughly testing and validating your Helm charts ensures they work as expected and reduces the risk of issues during deployment.

Helm Linting

Use helm lint to check your chart for common issues and misconfigurations before deploying it. This tool provides immediate feedback and helps catch errors early in the development process.

Command to Lint a Helm Chart:

helm lint myapp

Running this command ensures that your chart follows best practices and is free from syntax errors.

Automated Testing

Incorporate automated tests into your CI/CD pipeline to validate your Helm charts. Helm provides a test framework that allows you to define tests as Kubernetes Jobs.

Best Practices for Automated Testing:

• Write Simple Tests: Use Helm’s built-in test framework to create simple tests that verify the basic functionality of your deployment.

• Integrate with CI/CD: Ensure your tests run automatically in your CI/CD pipeline, catching issues before they reach production.

Example of a Helm Test Job:

apiVersion: batch/v1
kind: Job
metadata:
  name: "{{ .Release.Name }}-test-connection"
spec:
  template:
    spec:
      containers:
      - name: curl
        image: busybox
        command: ['curl', 'http://{{ .Release.Name }}-service']
      restartPolicy: Never

This test verifies that the service is accessible after deployment.

Continuous Integration with Helm

Integrate Helm into your CI/CD pipeline to automate chart testing, packaging, and deployment. This ensures consistent and reliable deployments across environments.

Best Practices for CI/CD Integration:

• Automate Linting and Testing: Ensure helm lint and your Helm tests run on every commit.

• Automate Chart Packaging and Release: Package and release new chart versions automatically based on successful tests.

Example of a Simple CI/CD Pipeline Step:

steps:
  - name: Lint and Test Helm Chart
    run: |
      helm lint myapp
      helm test myapp

This step automates linting and testing of the Helm chart in a CI/CD pipeline.

Documentation and Community Standards

Clear documentation and adherence to community standards are essential for creating charts that others can easily use and contribute to.

Writing Clear Documentation

Provide clear and comprehensive documentation for your Helm charts. This should include instructions on installation, configuration, and troubleshooting.

Best Practices for Documentation:

• Include a README.md: Document how to install and use the chart, including examples and explanations of values.

• Document Configuration Options: Clearly explain all configurable values in values.yaml, including their defaults and possible options.

Example of a README.md Structure:

# MyApp Helm Chart

## Introduction
This Helm chart installs MyApp on a Kubernetes cluster.

## Prerequisites
- Kubernetes 1.16+
- Helm 3.0+

## Installation
```bash
helm install myapp ./myapp

Configuration

Parameter	Description	Default
replicaCount	Number of replicas	2
image.repository	Image repository	nginx
image.tag	Image tag	1.19.0

Troubleshooting

Refer to the Helm documentation for troubleshooting common issues.

vbnetCopy codeThis structure provides a clear and organized way to communicate important information to users.

##### 4.1.5.2 Adhering to Community Standards

Follow established community standards when developing and maintaining your Helm charts. This includes using best practices for chart structure, naming, and versioning, as well as following guidelines set by popular Helm repositories like Artifact Hub.

**Best Practices for Community Standards:**
- **Contribute to Existing Charts**: Where possible, contribute improvements back to the community by submitting pull requests to existing charts.
- **Follow Repository Guidelines**: Adhere to the submission guidelines of the Helm repository you are contributing to, such as Artifact Hub.

#### 4.1.6 Summary

Following best practices when developing Helm charts ensures that your charts are maintainable, secure, and easy to use. By structuring your charts consistently, managing dependencies and versions effectively, and incorporating security and testing measures, you can create high-quality charts that meet the needs of your users. Clear documentation and adherence to community standards further enhance the usability and contribution potential of your charts.

In the next lesson, we’ll explore advanced Helm features and workflows, such as Helmfile and Helm secrets, to further streamline and secure your Kubernetes deployments.

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### Quiz Questions:
1. What are some best practices for structuring Helm charts?
2. Why is semantic versioning important in Helm chart development?
3. How can you secure sensitive data in Helm charts?
4. What is the purpose of `helm lint`, and how does it contribute to best practices?

### Hands-on Exercise:
- Review an existing Helm chart from a public repository. Identify areas where best practices are followed and areas where improvements could be made. Consider submitting a pull request to improve the chart according to the best practices covered in this lesson.

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This lesson equips you with the best practices needed to create and maintain high-quality Helm charts that are secure, maintain