Helm templating

Overview

Helm supports advanced templating while remaining easy to use when pre-prepared Helm charts are available. It enables the continuous evolution of Helm charts over time, allowing service developers to leverage them effectively.

Helm Charts

The helm-charts repository provides Helm charts for various backend services and infrastructure components.

Helm charts allow applications to be packaged with Kubernetes manifests and configuration values, providing a standardized and repeatable deployment method.

A typical Helm chart may include:

• Deployments: Manages pod lifecycle.
• Services: Defines networking access.
• Jobs / CronJobs: Handles scheduled tasks.
• Ingress / HTTPRoutes: Controls traffic routing.
• ConfigMaps / Secrets: Manages application configuration.

Example service helm chart

eit-ingress-service

Renders manifests (all configurable by values / parameters):

• service
• deployment
• RestTest cron job and job (optionally)
• ingress (optionally)
• HTTPRoute (optionally)

default values

example of values used for deployment of svc-blog-posts

Development and Testing of Helm Charts

To test Helm charts using snapshot tests, the following workflow is followed:

1. Create a test folder under tests/ in the repository.
2. Run the rendering script to generate Kubernetes manifests:

   tests/rerender-charts.sh
   

3. Manually verify the rendered manifests.
4. Store expected results for regression testing, ensuring they act as unit tests in the CI/CD pipeline.
5. Run tests manually via:

   ./tests/run-tests.sh
   

Part of the output of snapshot tests pipeline step

For additional details, refer to the README.md.

Helm Registry

The helm-registry repository acts as an artifact repository where Helm charts are stored after packaging and versioning.

Structure of the registry:

packages/{app-name}/{app-name}-{version}.tgz

Example helm chart packages:

packages/eit-ingress-service/eit-ingress-service-1.2.0.tgz
packages/eit-ingress-service/eit-ingress-service-1.1.8.tgz
packages/eit-keycloak/eit-keycloak-1.0.0.tgz

eit-ingress-service helm chart packages

This repository enables:

• Centralized storage of Helm charts for easier access and version management.
• Simplified chart distribution and deployment across environments.
• Easy access to Helm charts from pipelines, as they are stored in a standard Git repository.