Kubernetes GitOps Flux Repo

This is an example on how I would structure a 1:1 (repo-to-single cluster) git repo for a Kubernetes cluster. Kubernetes with Argo repo I created.

This example assumes (as I mentioned in the 1:1 part above) that it's a single repo for a single cluster. However, this can be modified (quite easily) for poly/mono repos or for multiple clusters. This is meant as a good starting point and not what your final repo will look like.

This repo is based on Flux, but uses the same(-ish) repo structure as my Argo CD example.

Structure

Below is an explanation on how this repo is laid out. You'll notice that I use Kustomize heavily. I do this since I follow the DRY principal when it comes to YAML files.

cluster-XXXX/ # 1
├── bootstrap # 2
│   ├── base
│   │   └── kustomization.yaml
│   └── overlays
│       └── default
│           └── kustomization.yaml
├── components # 3
│   ├── gitrepositories
│   │   ├── cluster-gitrepo.yaml
│   │   └── kustomization.yaml
│   ├── helmreleases
│   │   ├── kustomization.yaml
│   │   └── sample-quarkus.yaml
│   ├── helmrepositories
│   │   ├── kustomization.yaml
│   │   └── redhat-helm-charts.yaml
│   └── kustomizations
│       ├── core-components-kustomization.yaml
│       ├── kustomization.yaml
│       └── tenants-kustomization.yaml
├── core # 4
│   ├── gitops-controller
│   │   └── kustomization.yaml
│   └── sample-admin-workload
│       ├── kustomization.yaml
│       └── sample-admin-config.yaml
└── tenants # 5
    ├── bgd-blue
    │   ├── bgd-deployment.yaml
    │   └── kustomization.yaml
    └── myapp
        ├── kustomization.yaml
        ├── myapp-deployment.yaml
        ├── myapp-ns.yaml
        └── myapp-service.yaml

#	Directory Name	Description
1.	cluster-XXXX	This is the cluster name. This name should be unique to the specific cluster you're targeting. If you're using CAPI, this should be the name of your cluster, the output of kubectl get cluster
2.	bootstrap	This is where bootstrapping specifc configurations are stored. These are items that get the cluster/automation started. They are usually install manifests. base is where are the "common" YAML would live and overlays are configurations specific to the cluster. The kustomization.yaml file in default has cluster-XXXX/components/gitrepositories/, cluster-XXXX/components/helmreleases, cluster-XXXX/components/helmrepositories and cluster-XXXX/components/kustomizations as a part of it's bases config.
3.	components	This is where specific components for the GitOps Controller lives (in this case Flux) . gitrepositories is where all the configuration YAMLs to access this (and other) git repos live, helmrepositories is where the configuration for your helm repositories YAMLs live, helmreleases is where your HelmReleases live, and kustomizations are where Kustomizations for this cluster live. Other things that can live here are other Flux components (each in their repsective directories).
4.	core	This is where YAML for the core functionality of the cluster live. Here is where the Kubernetes administrator will put things that is necissary for the functionality of the cluster (like cluster configs or cluster workloads). Under gitops-controller is where you are using Flux to manage itself. The kustomization.yaml file uses cluster-XXXX/bootstrap/overlays/default in it's bases configuration. Everything in this core directory gets deployed as a part of the kustomization found under cluster-XXXX/components/kustomizations/core-components-kustomization.yaml. To add a new "core functionality" workoad, one needs to add a directory with some yaml in the core directory. See the sample-admin-config directory as an example.
5.	tenants	This is where the workloads for this cluster live. Similar to core, the tenants directory gets loaded as part of a kustomization that is under cluster-XXXX/components/kustomizations/tenants-kustomization.yaml. This is where Devlopers/Release Engineers do the work. They just need to commit a directory with some YAML and the kustomization takes care of creating the workload. Note that bgd-blue/kustomization.yaml file points to another Git repo. This is to show that you can host your YAML in one repo, or many repos.

Testing

To see this in action, first get yourself a cluster (using kind as an example)

kind create cluster

Then, just apply this repo.

until kubectl apply -k https://github.com/christianh814/example-kubernetes-goflux-repo/cluster-XXXX/bootstrap/overlays/default; do sleep 3; done

This should give you 2 kustomizations

$ kubectl get kustomizations -n flux-system 
NAME          READY   STATUS                                                            AGE
core          True    Applied revision: main/111881dc371dd1b2abd823450f01ee085aff3726   3m50s
tenants       True    Applied revision: main/111881dc371dd1b2abd823450f01ee085aff3726   3m50s

This should also load your git source

$ kubectl get gitrepositories -n flux-system
NAME                   URL                                                               READY   STATUS                                                            AGE
cluster-xxxx-gitrepo   https://github.com/christianh814/example-kubernetes-goflux-repo   True    Fetched revision: main/111881dc371dd1b2abd823450f01ee085aff3726   4m25s

Enjoy

Fork and Enjoy!

⚠️ Feel free to fork this and play around with it, but remember if you'll maybe have to change the where the bases are pointing to if you're changing names of things.