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.
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
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.
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
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=${GITHUB_REPO} \
--branch=main \
--personal \
--path=cluster/dev
Assuming you want to add custom annotations and labels to the Flux controllers in production.
First clone your repo locally:
git clone https://github.com/${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