One chart to rule them all

A generic Helm chart for your application deployments.

Because no-one can remember the Kubernetes yaml syntax.

https://gimlet.io/docs/reference/onechart-reference

Getting started

OneChart is a generic Helm Chart for web applications. The idea is that most Kubernetes manifest look alike, only very few parts actually change.

Add the Onechart Helm repository:

helm repo add onechart https://chart.onechart.dev

Set your image name and version, the boilerplate is generated.

helm template my-release onechart/onechart \
  --set image.repository=nginx \
  --set image.tag=1.19.3

The example below deploys your application image, sets environment variables and configures the Kubernetes Ingress domain name:

helm repo add onechart https://chart.onechart.dev
helm template my-release onechart/onechart -f values.yaml

# values.yaml
image:
  repository: my-app
  tag: fd803fc
vars:
  VAR_1: "value 1"
  VAR_2: "value 2"
ingress:
  annotations:
    kubernetes.io/ingress.class: nginx
  host: my-app.mycompany.com

Alternative: using an OCI repository

You can also template and install onechart from an OCI repository as follows:

Check the generated Kubernetes yaml:

helm template my-release oci://ghcr.io/gimlet-io/onechart --version 0.62.0 \
  --set image.repository=nginx \
  --set image.tag=1.19.3

Deploy with Helm:

helm install my-release oci://ghcr.io/gimlet-io/onechart --version 0.62.0 \
  --set image.repository=nginx \
  --set image.tag=1.19.3

See all Examples

Contribution Guidelines

Thank you for your interest in contributing to the Gimlet project.

Below are some guidelines and best practices for contributing to this repository:

Issues

If you are running a fork of OneChart and would like to upstream a feature, please open a pull request for it.

New Features

If you are planning to add a new feature to OneChart, please open an issue for it first. Helm charts are prone to having too many features, and OneChart want to keep the supported use-cases in-check. Proposed features have to be generally applicable, targeting newcomers to the Kubernetes ecosystem.

Pull Request Process

• Fork the repository.
• Create a new branch and make your changes.
• Open a pull request with detailed commit message and reference issue number if applicable.
• A maintainer will review your pull request, and help you throughout the process.

Development

Development of OneChart does not differ from developing a regular Helm chart.

The source for OneChart is under charts/onechart where you can locate the Chart.yaml, values.yaml and the templates.

We write unit tests for our helm charts. Pull requests are only accepted with proper test coverage.

The tests are located under charts/onechart/test and use the https://github.com/helm-unittest/helm-unittest Helm plugin to run the tests.

For installation, refer to the CI workflow at .github/workflows/build.yaml.

Release process

make all to test and package the Helm chart. The chart archives are put under docs/ together with the Helm repository manifest (index.yaml) It is then served with Github Pages on https://chart.onechart.dev

Github Actions is used to automate the make calls on git tag events.