fluxcd / flux2-kustomize-helm-example

Minimizing Duplication - fluxcd/flux2-kustomize-helm-example

In the project “https://github.com/fluxcd/flux2-kustomize-helm-example/”, the repository structure and Kustomize patches help reduce code duplication and improve maintainability by using Kustomize for configuration management and Helm for deploying applications.

Kustomize is a standalone tool to customize Kubernetes objects through a kustomization file. It allows for reusing and overlaying base configurations, minimizing duplication. The repository structure in “https://github.com/fluxcd/flux2-kustomize-helm-example/” demonstrates this approach with the following directory structure:

flux2-kustomize-helm-example/
├── clusters/
│   └── dev/
│       └── flux-system/
│           ├── gotk-components.yaml
│           ├── gotk-sync.yaml
│           └── kustomization.yaml
└── overlays/
└── dev/
├── kustomization.yaml
├── kustomize-controller.yaml
├── helm-controller.yaml
├── notification-controller.yaml
└── source-controller.yaml

The kustomization.yaml files in the overlays/dev/ directory use Kustomize patches to customize the base configurations in clusters/dev/flux-system/. For example, the source-controller.yaml in the overlays/dev/ directory contains patches to customize the source-controller Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
name: source-controller
patchesStrategicMerge:
- patch: |
- op: add
path: /spec/template/spec/containers/0/args/-
value: --helm-cache-max-size=10
- op: add
path: /spec/template/spec/containers/0/args/-
value: --helm-cache-ttl=60m
- op: add
path: /spec/template/spec/containers/0/args/-
value: --helm-cache-purge-interval=5m

This approach allows for reusing the base configurations and customizing them for specific environments (in this case, dev), minimizing duplication and improving maintainability.

Additionally, the project uses Helm for deploying applications, which also helps reduce duplication. Helm Charts are reusable packages that can be shared and used across different projects and environments. The Chart.yaml file in a Helm Chart defines the chart’s metadata, and the values.yaml file contains default configuration values that can be overridden during installation. This separation of concerns allows for easy customization and reuse of Helm Charts.

In the project “https://github.com/fluxcd/flux2-kustomize-helm-example/”, the Chart.yaml and values.yaml files for the PodInfo application are located in the charts/podinfo/ directory. The Kustomization file in overlays/dev/ references the PodInfo Helm Chart and provides custom values for the dev environment:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
- ../../charts/podinfo

helmCharts:
- chart: podinfo
values:
- values.yaml
- overlay-values.yaml

The overlay-values.yaml file in overlays/dev/ contains custom values for the dev environment:

image:
tag: v2.22.0

replicaCount: 3

service:
type: ClusterIP
port: 80
targetPort: 9898

By using Kustomize and Helm together, the project “https://github.com/fluxcd/flux2-kustomize-helm-example/” demonstrates best practices for minimizing duplication and improving maintainability in a GitOps environment.

Sources: