In this Tutorial we try Flux CD with multiple stages and minikube clusters using kustomize.

Prerequisites

• Docker installed
• Minikube installed
• fluxctl installed
• Github account
• kubectx installed
• kubectl installed

Install minikube clusters

We setup two minikube clusters on our local machine named mini-acpt and mini-prod.

minikube start --profile mini-acpt
minikube start --profile mini-prod

Create empty Github repository

Login to your Github account and create an empty repository named flux-multi-stage. Clone the repository to your local machine.

Install flux on minikube clusters

First we install flux on our mini-acpt cluster. Adjust the GHUSER variable and --git-url parameter. With the --git-path parameter we configure flux to only check for manifests under this path in the Github repository. Switch the context to the mini-acpt cluster and create the flux namespace.

kubectx mini-acpt
kubectl create ns flux

export GHUSER="your user"
fluxctl install \
--git-user=${GHUSER} \
--git-email=${GHUSER}@users.noreply.github.com \
--git-path=acpt \
--manifest-generation=true \
--git-url=git@github.com:${GHUSER}/flux-multi-stage \
--namespace=flux | kubectl apply -f -

Now let’s do the same for the mini-prod cluster changing the --git-path parameter to prod.

kubectx mini-prod
kubectl create ns flux

export GHUSER="your user"
fluxctl install \
--git-user=${GHUSER} \
--git-email=${GHUSER}@users.noreply.github.com \
--git-path=prod \
--manifest-generation=true \
--git-url=git@github.com:${GHUSER}/flux-multi-stage \
--namespace=flux | kubectl apply -f -

Now we need to add the deploy key to our Github repository so that flux can communicate with it.

kubectx mini-acpt
fluxctl identity --k8s-fwd-ns flux

Add public key to our Github repository as a deploy key with write permission! Then we need to do the same for the mini-prod cluster.

kubectx mini-prod
fluxctl identity --k8s-fwd-ns flux

Add a namespace to the clusters

Go to your cloned repository flux-multi-stage. Add the file .flux.yaml to the root with the following content:

version: 1
patchUpdated:
  generators:
    - command: kustomize build .
patchFile: flux-patch.yaml

Add the following three directories to the root of the repository base, acpt, prod.

Change to the base directory. Create the file demo-ns.yaml in it with the following content:

apiVersion: v1
kind: Namespace
metadata:
  labels:
    name: demo
  name: demo

In the same base directory create a new file kustomization.yaml with the following content:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- demo-ns.yaml

Then create in the prod and acpt directory a new file named kustomization.yaml with the following content:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
bases:
- ../base/

Our repository now should look like:

.
├── acpt
│   └── kustomization.yaml
├── base
│   ├── demo-ns.yaml
│   └── kustomization.yaml
├── .flux.yaml
├── LICENSE
├── prod
│   └── kustomization.yaml
└── README.md

Commit and push everything. Flux syncs the repository every 5 minutes. After that we should find our demo namespace created in both clusters.

Go and list the namespaces in our clusters.

kubectx mini-acpt
kubectl get ns

kubectx mini-prod
kubectl get ns

The output should be like this:

kubectl get ns   
NAME                   STATUS   AGE
default                Active   4h17m
demo                   Active   5m13s
flux                   Active   53m
kube-node-lease        Active   4h17m
kube-public            Active   4h17m
kube-system            Active   4h17m
kubernetes-dashboard   Active   52m

As shown above the demo namespace got created.

Add a pod to the clusters

Add a new file to the base directory named nginx-dep.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
  namespace: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
template:
  metadata:
    labels:
      app: nginx
  spec:
    containers:
    - image: nginx
      name: nginx

Edit the kustomization.yaml and add the new deployment:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- demo-ns.yaml
- nginx-dep.yaml

Change to the acpt directory and add a file named flux-patch.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  annotations:
    flux.weave.works/automated: "true"
  name: nginx
  namespace: demo

The above annotation will deploy new images automatically.

Change to the prod directory and add a file named flux-patch.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  annotations:
    flux.weave.works/automated: "false"
  name: nginx
  namespace: demo

With the above annotation we prevent autmatic image updates in production.

In the prod directory add a new file named nginx-dep.yaml wit the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
  namespace: demo
spec:
  replicas: 2

With this kustomization we scale the nginx to 2 in production. Edit the kustomization.yam to add the file above:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
bases:
- ../base/
patchesStrategicMerge:
- nginx-dep.yaml

Commit and push everything. Flux syncs the repository every 5 minutes. After that we should find in acpt one nginx pod running and in prod two pod’s.

Example:

kubectl -n demo get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx-57b5958569-f4znb   1/1     Running   0          16m
nginx-57b5958569-ngktd   1/1     Running   0          16m

Stop the clusters

To stop the clusters enter

minikube stop --profile mini-prod
minikube stop --profile mini-acpt

Summary

In this tutorial we setup two clusters, installed Flux CD on them and deployed some workload.