fluxcd / flux2-kustomize-helm-example

Application Deployment - fluxcd/flux2-kustomize-helm-example

Application Deployment using Helm Charts and Flux

In this guide, we will demonstrate how to deploy an application using Helm charts and configure it for different environments using Flux. We will use the flux2-kustomize-helm-example project as an example.

Prerequisites

Before we begin, make sure you have the following tools installed:

Design Philosophy

The project follows the GitOps philosophy, which means that all the application configuration and deployment artifacts are stored in a Git repository, and changes to the configuration are made by modifying the Git repository. Flux monitors the Git repository and automatically applies the changes to the cluster.

Programming Languages

The project uses the following programming languages:

  • Helm charts (written in YAML)
  • Kustomize (written in YAML)

Key Technologies and Dependencies

The project uses the following technologies and dependencies:

  • Flux: a GitOps tool for Kubernetes
  • Helm: a package manager for Kubernetes
  • Kustomize: a tool for customizing Kubernetes objects
  • GitHub: a Git repository hosting service
  • Cert-Manager: a tool for managing TLS certificates
  • Ingress-NGINX: a Kubernetes Ingress controller
  • Kubernetes: a container orchestration platform
  • HelmRepository: a Helm repository for hosting Helm charts
  • HelmRelease: a Helm release for deploying Helm charts
  • Kustomize API: an API for customizing Kubernetes objects

Deploying the Application

To deploy the application, follow these steps:

  1. Install Flux in the flux-system namespace:
$ flux install --components=source-controller,kustomize-controller,helm-controller,notification-controller
  1. Configure the deploy key:
$ flux create secret git deploy-key --url=https://github.com/fluxcd/flux2-kustomize-helm-example --key=<path-to-deploy-key>
  1. Create a Kustomization object to deploy the application:
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
wait: true
timeout: 3m0s
retryInterval: 2m0s
prune: true
force: false
targetNamespace: apps
sourceRef:
kind: GitRepository
name: webapp
namespace: apps
path: ./deploy/production
  1. Create a HelmRelease object to deploy the application:
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
chart:
spec:
chart: webapp
version: <chart-version>
sourceRef:
kind: GitRepository
name: webapp
namespace: apps
targetNamespace: apps
  1. Create a GitRepository object to reference the Git repository:
apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: GitRepository
metadata:
name: webapp
namespace: apps
spec:
url: https://github.com/fluxcd/flux2-kustomize-helm-example
ref:
branch: main
  1. Apply the configuration to the cluster:
$ kubectl apply -f <path-to-configuration>

Configuring the Application for Different Environments

To configure the application for different environments, we can use Kustomize overlays. An overlay is a directory that contains Kustomize patches that modify the base configuration.

For example, to create an overlay for the production environment, we can create a directory called overlays/production and add the following Kustomize patch:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
wait: true
timeout: 3m0s
retryInterval: 2m0s
prune: true
force: false
targetNamespace: apps
patchesStrategicMerge:
- patch.yaml

The patch.yaml file contains the Kustomize patches that modify the base configuration. For example, to set the replicaCount to 2 and change the service type to NodePort, we can add the following patch:

replicaCount: 2
service:
type: NodePort

To enable the overlay, we need to add a Kustomization object to the flux-system namespace:

apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
name: core-webapp
namespace: flux-system
spec:
interval: 5m
sourceRef:
kind: GitRepository
name: webapp
namespace: apps
path: ./overlays/production

Possible Options

The following options are possible when deploying an application using Helm charts and Flux:

  • Using Helm repositories to host Helm charts
  • Using Helm values to customize Helm charts
  • Using Kustomize overlays to customize Kubernetes objects
  • Using Kustomize patches to modify Kubernetes objects
  • Using GitOps to automate the deployment of applications
  • Using Flux to monitor Git repositories and apply changes to the cluster

Examples

The following examples demonstrate how to use the different options:

  • Using Helm repositories:
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
chart:
spec:
chart: webapp
version: <chart-version>
sourceRef:
kind: HelmRepository
name: webapp
namespace: apps
targetNamespace: apps
  • Using Helm values:
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
chart:
spec:
chart: webapp
version: <chart-version>
sourceRef:
kind: GitRepository
name: webapp
namespace: apps
values:
- replicaCount: 2
- service:
type: NodePort
targetNamespace: apps
  • Using Kustomize overlays:
apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
wait: true
timeout: 3m0s
retryInterval: 2m0s
prune: true
force: false
targetNamespace: apps
sourceRef:
kind: GitRepository
name: webapp
namespace: apps
path: ./deploy/production
  • Using Kustomize patches:
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
metadata:
name: webapp
namespace: apps
spec:
interval: 60m0s
wait: true
timeout: 3m0s
retryInterval: 2m0s
prune: true
force: false
targetNamespace: apps