jaya-venkatesan/flux2-kustomize-helm-example

A GitOps workflow example for multi-env deployments with Flux, Kustomize and Helm.

flux2-kustomize-helm-example

For this example we assume a scenario with two clusters: staging and production. The end goal is to leverage Flux and Kustomize to manage both clusters while minimizing duplicated declarations.

We will configure Flux to install, test and upgrade a demo app using HelmRepository and HelmRelease custom resources. Flux will monitor the Helm repository, and it will automatically upgrade the Helm releases to their latest chart version based on semver ranges.

Prerequisites

You will need a Kubernetes cluster version 1.16 or newer and kubectl version 1.18. For a quick local test, you can use Kubernetes kind. Any other Kubernetes setup will work as well though.

In order to follow the guide you'll need a GitHub account and a personal access token that can create repositories (check all permissions under repo).

Install the Flux CLI on MacOS and Linux using Homebrew:

brew install fluxcd/tap/flux

Or install the CLI by downloading precompiled binaries using a Bash script:

curl -s https://toolkit.fluxcd.io/install.sh | sudo bash

Repository structure

The Git repository contains the following top directories:

• apps dir contains Helm releases with a custom configuration per cluster
• infrastructure dir contains common infra tools such as NGINX ingress controller and Helm repository definitions
• clusters dir contains the Flux configuration per cluster

├── apps
│   ├── base
│   ├── production 
│   └── staging
├── infrastructure
│   ├── nginx
│   ├── redis
│   └── sources
└── clusters
    ├── production
    └── staging

The apps configuration is structured into:

• apps/base/ dir contains namespaces and Helm release definitions
• apps/production/ dir contains the production Helm release values
• apps/staging/ dir contains the staging values

./apps/
├── base
│   └── podinfo
│       ├── kustomization.yaml
│       ├── namespace.yaml
│       └── release.yaml
├── production
│   ├── kustomization.yaml
│   └── podinfo-patch.yaml
└── staging
    ├── kustomization.yaml
    └── podinfo-patch.yaml

In apps/base/podinfo/ dir we have a HelmRelease with common values for both clusters:

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: podinfo
  namespace: podinfo
spec:
  releaseName: podinfo
  chart:
    spec:
      chart: podinfo
      sourceRef:
        kind: HelmRepository
        name: podinfo
        namespace: flux-system
  interval: 5m
  values:
    cache: redis-master.redis:6379
    ingress:
      enabled: true
      annotations:
        kubernetes.io/ingress.class: nginx
      path: "/*"

In apps/staging/ dir we have a Kustomize patch with the staging specific values:

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: podinfo
spec:
  chart:
    spec:
      version: ">=1.0.0-alpha"
  test:
    enable: true
  values:
    ingress:
      hosts:
        - podinfo.staging

Note that with version: ">=1.0.0-alpha" we configure Flux to automatically upgrade the HelmRelease to the latest chart version including alpha, beta and pre-releases.

In apps/production/ dir we have a Kustomize patch with the production specific values:

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: podinfo
  namespace: podinfo
spec:
  chart:
    spec:
      version: ">=1.0.0"
  values:
    ingress:
      hosts:
        - podinfo.production

Note that with version: ">=1.0.0" we configure Flux to automatically upgrade the HelmRelease to the latest stable chart version (alpha, beta and pre-releases will be ignored).

Infrastructure:

./infrastructure/
├── nginx
│   ├── kustomization.yaml
│   ├── namespace.yaml
│   └── release.yaml
├── redis
│   ├── kustomization.yaml
│   ├── namespace.yaml
│   └── release.yaml
└── sources
    ├── bitnami.yaml
    ├── kustomization.yaml
    └── podinfo.yaml

In infrastructure/sources/ dir we have the Helm repositories definitions:

apiVersion: source.toolkit.fluxcd.io/v1beta1
kind: HelmRepository
metadata:
  name: podinfo
spec:
  interval: 5m
  url: https://stefanprodan.github.io/podinfo
---
apiVersion: source.toolkit.fluxcd.io/v1beta1
kind: HelmRepository
metadata:
  name: bitnami
spec:
  interval: 30m
  url: https://charts.bitnami.com/bitnami

Note that with interval: 5m we configure Flux to pull the Helm repository index every five minutes. If the index contains a new chart version that matches a HelmRelease semver range, Flux will upgrade the release.

Bootstrap staging and production

The clusters dir contains the Flux configuration:

./clusters/
├── production
│   ├── apps.yaml
│   └── infrastructure.yaml
└── staging
    ├── apps.yaml
    └── infrastructure.yaml

In clusters/staging/ dir we have the Kustomization definitions:

apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
  name: apps
  namespace: flux-system
spec:
  interval: 10m0s
  dependsOn:
    - name: infrastructure
  sourceRef:
    kind: GitRepository
    name: flux-sytem
  path: ./apps/staging
  prune: true
  validation: client
---
apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
  name: infrastructure
  namespace: flux-system
spec:
  interval: 10m0s
  sourceRef:
    kind: GitRepository
    name: flux-system
  path: ./infrastructure

Note that with path: ./apps/staging we configure Flux to sync the staging Kustomize overlay and with dependsOn we tell Flux to create the infrastructure items before deploying the apps.

Fork this repository on your personal GitHub account and export your GitHub access token, username and repo name:

export GITHUB_TOKEN=<your-token>
export GITHUB_USER=<your-username>
export GITHUB_REPO=<repository-name>

Verify that your staging cluster satisfies the prerequisites with:

flux check --pre

Set the kubectl context to your staging cluster and bootstrap Flux:

flux bootstrap github \
    --context=staging \
    --owner=${GITHUB_USER} \
    --repository=${GITHUB_REPO} \
    --branch=main \
    --personal \
    --path=cluster/staging

The bootstrap command commits the manifests for the Flux components in clusters/staging/flux-system dir and creates a deploy key with read-only access on GitHub, so it can pull changes inside the cluster.

Watch for the Helm releases being install on staging:

$ watch flux get helmreleases --all-namespaces 
NAMESPACE	NAME   	REVISION	SUSPENDED	READY	MESSAGE                          
nginx    	nginx  	5.6.14  	False    	True 	release reconciliation succeeded	
podinfo  	podinfo	5.0.3   	False    	True 	release reconciliation succeeded	
redis    	redis  	11.3.4  	False    	True 	release reconciliation succeeded

Verify that the demo app can be accessed via ingress:

$ kubectl -n nginx port-forward svc/nginx-ingress-controller 8080:80 &

$ curl -H "Host: podinfo.staging" http://localhost:8080
{
  "hostname": "podinfo-59489db7b5-lmwpn",
  "version": "5.0.3"
}

Bootstrap Flux on production by setting the context and path to your production cluster:

flux bootstrap github \
    --context=production \
    --owner=${GITHUB_USER} \
    --repository=${GITHUB_REPO} \
    --branch=main \
    --personal \
    --path=cluster/production

Watch the production reconciliation:

$ watch flux get kustomizations
NAME          	REVISION                                        READY
apps          	main/797cd90cc8e81feb30cfe471a5186b86daf2758d	True
flux-system   	main/797cd90cc8e81feb30cfe471a5186b86daf2758d	True
infrastructure	main/797cd90cc8e81feb30cfe471a5186b86daf2758d	True

Add clusters

If you want to add a cluster to your fleet, first clone your repo locally:

git clone https://github.com/${GITHUB_USER}/${GITHUB_REPO}.git
cd ${GITHUB_REPO}

Create a dir inside clusters with your cluster name:

mkdir -p clusters/dev

Copy the sync manifests from staging:

cp clusters/staging/infrastructure.yaml clusters/dev
cp clusters/staging/apps.yaml clusters/dev

You could create a dev overlay inside apps, make sure to change the spec.path inside clusters/dev/apps.yaml to path: ./apps/dev.

Push the changes to main branch:

git add -A && git commit -m "add dev cluster" && git push

Set the kubectl context and path to your dev cluster and bootstrap Flux:

flux bootstrap github \
    --context=dev \
    --owner=${GITHUB_USER} \
    --repository=${GITHUB_REPO} \
    --branch=main \
    --personal \
    --path=cluster/dev

Customize Flux manifests

Assuming you want to add custom annotations and labels to the Flux controllers in production.

First clone your repo locally:

git clone https://github.com/${GITHUB_USER}/${GITHUB_REPO}.git
cd ${GITHUB_REPO}

Create a Kustomize patch and set the metadata for source-controller and kustomize-controller pods:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: source-controller
  namespace: flux-system
spec:
  template:
    metadata:
      annotations:
        custom: annotation
      labels:
        custom: label
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: kustomize-controller
  namespace: flux-system
spec:
  template:
    metadata:
      annotations:
        custom: annotation
      labels:
        custom: label

Save the above file as flux-system-patch.yaml inside the clusters/production dir.

Create clusters/production/kustomization.yaml file with the following content:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  - flux-system
  - infrastructure.yaml
  - apps.yaml
patchesStrategicMerge:
  - flux-system-patch.yaml

Push the changes to main branch:

git add -A && git commit -m "add production metadata" && git push

Flux will detect the change and will update itself on the production cluster. You can request an immediate reconciliation with:

flux reconcile kustomization flux-system \
--context=production \
--with-source