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Template for deploying k3s backed by Flux

Highly opinionated template for deploying a single k3s cluster with Ansible and Terraform backed by Flux and SOPS.

The purpose here is to showcase how you can deploy an entire Kubernetes cluster and show it off to the world using the GitOps tool Flux. When completed, your Git repository will be driving the state of your Kubernetes cluster. In addition with the help of the Ansible, Terraform and Flux SOPS integrations you'll be able to commit Age encrypted secrets to your public repo.

Overview

👋 Introduction

The following components will be installed in your k3s cluster by default. They are only included to get a minimum viable cluster up and running. You are free to add / remove components to your liking but anything outside the scope of the below components are not supported by this template.

Feel free to read up on any of these technologies before you get started to be more familiar with them.

  • cert-manager - SSL certificates - with Cloudflare DNS challenge
  • calico - CNI (container network interface)
  • echo-server - REST Server Tests (Echo-Server) API (useful for debugging HTTP issues)
  • external-dns - Automatically configure external DNS servers for Kubernetes Ingresses and Services
  • flux - GitOps tool for deploying manifests from the cluster directory
  • hajimari - start page with ingress discovery
  • k8s_gateway - DNS resolver for all types of external Kubernetes resources
  • kube-vip - layer 2 load balancer for the Kubernetes control plane
  • local-path-provisioner - default storage class provided by k3s
  • metallb - bare metal load balancer
  • reloader - restart pods when Kubernetes configmap or secret changes
  • reflector - mirror configmaps or secrets to other Kubernetes namespaces
  • system-upgrade-controller - (opt-in) automate upgrading k3s
  • traefik - ingress controller

For provisioning the following tools will be used:

  • Ubuntu - this is a pretty universal operating system that supports running all kinds of home related workloads in Kubernetes
  • Ansible - this will be used to provision the Ubuntu operating system to be ready for Kubernetes and also to install k3s
  • Terraform - in order to help with the DNS settings this will be used to provision an already existing Cloudflare domain and certain DNS settings

📝 Prerequisites

Note: This template has not been tested on cloud providers like AWS EC2, Hetzner, Scaleway etc... Those cloud offerings probably have a better way of provsioning a Kubernetes cluster and it's advisable to use those instead of the Ansible playbooks included here. This repository can still be used for the GitOps/Flux portion if there's a cluster working in one those environments.

💻 Systems

  • One or more nodes with a fresh install of Ubuntu Server 22.04.
    • These nodes can be bare metal or VMs.
    • An odd number of control plane nodes, greater than or equal to 3 is required if deploying more than one control plane node.
  • A Cloudflare account with a domain, this will be managed by Terraform.
  • Some experience in debugging problems and a positive attitude ;)

📍 It is recommended to have 3 master nodes for a highly available control plane.

🔧 Tools

📍 You should install the below CLI tools on your workstation. Make sure you pull in the latest versions.

Required

Tool Purpose
ansible Preparing Ubuntu for Kubernetes and installing k3s
direnv Exports env vars based on present working directory
flux Operator that manages your k8s cluster based on your Git repository
age A simple, modern and secure encryption tool (and Go library) with small explicit keys, no config options, and UNIX-style composability.
go-task A task runner / simpler Make alternative written in Go
ipcalc Used to verify settings in the configure script
jq Used to verify settings in the configure script
yq Used to verify settings in the configure script
kubectl Allows you to run commands against Kubernetes clusters
sops Encrypts k8s secrets with Age
terraform Prepare a Cloudflare domain to be used with the cluster

Optional

Tool Purpose
helm Manage Kubernetes applications
kustomize Template-free way to customize application configuration
pre-commit Runs checks pre git commit
gitleaks Scan git repos (or files) for secrets
prettier Prettier is an opinionated code formatter.

⚠️ pre-commit

It is advisable to install pre-commit and the pre-commit hooks that come with this repository. sops-pre-commit and gitleaks will check to make sure you are not by accident committing your secrets un-encrypted.

After pre-commit is installed on your machine run:

task pre-commit:init

Remember to run this on each new clone of the repository for it to have effect.

Commands are of interest, for learning purposes:

This command makes it so pre-commit runs on git commit, and also installs environments per the config file.

pre-commit install --install-hooks

This command checks for new versions of hooks, though it will occasionally make mistakes, so verify its results.

pre-commit autoupdate

📂 Repository structure

The Git repository contains the following directories under cluster and are ordered below by how Flux will apply them.

  • base directory is the entrypoint to Flux
  • crds directory contains custom resource definitions (CRDs) that need to exist globally in your cluster before anything else exists
  • core directory (depends on crds) are important infrastructure applications (grouped by namespace) that should never be pruned by Flux
  • apps directory (depends on core) is where your common applications (grouped by namespace) could be placed, Flux will prune resources here if they are not tracked by Git anymore
cluster
├── apps
│   ├── default
│   ├── kube-system
│   ├── networking
│   └── system-upgrade
├── base
│   └── flux-system
├── core
│   ├── cert-manager
│   ├── kube-system
│   ├── metallb-system
│   └── namespaces
└── crds
    ├── cert-manager
    ├── system-upgrade-controller
    └── traefik

🚀 Lets go

Very first step will be to create a new repository by clicking the Use this template button on this page.

Clone the repo to you local workstation and cd into it.

📍 All of the below commands are run on your local workstation, not on any of your cluster nodes.

🔐 Setting up Age

📍 Here we will create a Age Private and Public key. Using SOPS with Age allows us to encrypt and decrypt secrets.

  1. Create a Age Private / Public Key

    age-keygen -o age.agekey

  2. Set up the directory for the Age key and move the Age file to it

    mkdir -p ~/.config/sops/age
mv age.agekey ~/.config/sops/age/keys.txt

  3. Export the SOPS_AGE_KEY_FILE variable in your bashrc, zshrc or config.fish and source it, e.g.

    export SOPS_AGE_KEY_FILE=~/.config/sops/age/keys.txt
source ~/.bashrc

  4. Fill out the Age public key in the .config.env under BOOTSTRAP_AGE_PUBLIC_KEY, note the public key should start with age...

☁️ Global Cloudflare API Key

In order to use Terraform and cert-manager with the Cloudflare DNS challenge you will need to create a API key.

  1. Head over to Cloudflare and create a API key by going here.

  2. Under the API Keys section, create a global API Key.

  3. Use the API Key in the configuration section below.

📍 You may wish to update this later on to a Cloudflare API Token which can be scoped to certain resources. I do not recommend using a Cloudflare API Key, however for the purposes of this template it is easier getting started without having to define which scopes and resources are needed. For more information see the Cloudflare docs on API Keys and Tokens.

📄 Configuration

📍 The .config.env file contains necessary configuration that is needed by Ansible, Terraform and Flux.

  1. Copy the .config.sample.env to .config.env and start filling out all the environment variables. All are required unless otherwise noted in the comments.

  2. Once that is done, verify the configuration is correct by running ./configure.sh --verify

  3. If you do not encounter any errors run ./configure.sh to start having the script wire up the templated files and place them where they need to be.

⚡ Preparing Ubuntu with Ansible

📍 Here we will be running a Ansible Playbook to prepare Ubuntu for running a Kubernetes cluster.

📍 Nodes are not security hardened by default, you can do this with dev-sec/ansible-collection-hardening or similar if it supports Ubuntu 22.04.

  1. Ensure you are able to SSH into your nodes from your workstation using your private ssh key. This is how Ansible is able to connect to your remote nodes. How to configure SSH key-based authentication

  2. Install the deps by running task ansible:deps

  3. Verify Ansible can view your config by running task ansible:list

  4. Verify Ansible can ping your nodes by running task ansible:ping

  5. Finally, run the Ubuntu Prepare playbook by running task ansible:prepare

  6. If everything goes as planned you should see Ansible running the Ubuntu Prepare Playbook against your nodes.

⛵ Installing k3s with Ansible

📍 Here we will be running a Ansible Playbook to install k3s with this wonderful k3s Ansible galaxy role. After completion, Ansible will drop a kubeconfig in ./provision/kubeconfig for use with interacting with your cluster with kubectl.

☢️ If you run into problems, you can run task ansible:nuke to destroy the k3s cluster and start over.

  1. Verify Ansible can view your config by running task ansible:list

  2. Verify Ansible can ping your nodes by running task ansible:ping

  3. Run the k3s install playbook by running task ansible:install

  4. If everything goes as planned you should see Ansible running the k3s install Playbook against your nodes.

  5. Verify the nodes are online

    kubectl --kubeconfig=./provision/kubeconfig get nodes
# NAME           STATUS   ROLES                       AGE     VERSION
# k8s-0          Ready    control-plane,master      4d20h   v1.21.5+k3s1
# k8s-1          Ready    worker                    4d20h   v1.21.5+k3s1

☁️ Configuring Cloudflare DNS with Terraform

📍 Review the Terraform scripts under ./provision/terraform/cloudflare/ and make sure you understand what it's doing (no really review it). If your domain already has existing DNS records be sure to export those DNS settings before you continue.

  1. Pull in the Terraform deps by running task terraform:init

  2. Review the changes Terraform will make to your Cloudflare domain by running task terraform:plan

  3. Finally have Terraform execute the task by running task terraform:apply

If Terraform was ran successfully you can log into Cloudflare and validate the DNS records are present. The cluster application external-dns will be managing the rest of the DNS records you will need.

🔹 GitOps with Flux

📍 Here we will be installing flux after some quick bootstrap steps.

  1. Verify Flux can be installed

    flux --kubeconfig=./provision/kubeconfig check --pre
# ► checking prerequisites
# ✔ kubectl 1.21.5 >=1.18.0-0
# ✔ Kubernetes 1.21.5+k3s1 >=1.16.0-0
# ✔ prerequisites checks passed

  2. Pre-create the flux-system namespace

    kubectl --kubeconfig=./provision/kubeconfig create namespace flux-system --dry-run=client -o yaml | kubectl --kubeconfig=./provision/kubeconfig apply -f -

  3. Add the Age key in-order for Flux to decrypt SOPS secrets

    cat ~/.config/sops/age/keys.txt |
    kubectl --kubeconfig=./provision/kubeconfig \
    -n flux-system create secret generic sops-age \
    --from-file=age.agekey=/dev/stdin

    📍 Variables defined in ./cluster/base/cluster-secrets.sops.yaml and ./cluster/base/cluster-settings.yaml will be usable anywhere in your YAML manifests under ./cluster except ./cluster/base

  4. Verify the ./cluster/base/cluster-secrets.sops.yaml and ./cluster/core/cert-manager/secret.sops.yaml files are encrypted with SOPS

  5. If you verified all the secrets are encrypted, you can delete the tmpl directory now

  6. Push you changes to git

    git add -A
git commit -m "initial commit"
git push

  7. Install Flux

    📍 Due to race conditions with the Flux CRDs you will have to run the below command twice. There should be no errors on this second run.

    kubectl --kubeconfig=./provision/kubeconfig apply --kustomize=./cluster/base/flux-system
# namespace/flux-system configured
# customresourcedefinition.apiextensions.k8s.io/alerts.notification.toolkit.fluxcd.io created
# ...
# unable to recognize "./cluster/base/flux-system": no matches for kind "Kustomization" in version "kustomize.toolkit.fluxcd.io/v1beta1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "GitRepository" in version "source.toolkit.fluxcd.io/v1beta1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1beta1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1beta1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1beta1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1beta1"

  8. Verify Flux components are running in the cluster

    kubectl --kubeconfig=./provision/kubeconfig get pods -n flux-system
# NAME                                       READY   STATUS    RESTARTS   AGE
# helm-controller-5bbd94c75-89sb4            1/1     Running   0          1h
# kustomize-controller-7b67b6b77d-nqc67      1/1     Running   0          1h
# notification-controller-7c46575844-k4bvr   1/1     Running   0          1h
# source-controller-7d6875bcb4-zqw9f         1/1     Running   0          1h

🎤 Verification Steps

Mic check, 1, 2

  1. View the Flux kustomizations

    kubectl --kubeconfig=./provision/kubeconfig get kustomizations --all-namespaces

  2. View all the Flux Helm Releases

    kubectl --kubeconfig=./provision/kubeconfig get helmreleases --all-namespaces

  3. View all the Pods

    kubectl --kubeconfig=./provision/kubeconfig get pods --all-namespaces

🏆 Congratulations if all goes smooth you'll have a Kubernetes cluster managed by Flux, your Git repository is driving the state of your cluster.

☢️ If you run into problems, you can run task ansible:nuke to destroy the k3s cluster and start over.

🧠 Now it's time to pause and go get some coffee ☕ because next is describing how DNS is handled.

📣 Post installation

🌐 DNS

📍 The external-dns application created in the networking namespace will handle creating public DNS records. By default, echo-server is the only public domain exposed on your Cloudflare domain. In order to make additional applications public you must set an ingress annotation like in the HelmRelease for echo-server. You do not need to use Terraform to create additional DNS records unless you need a record outside the purposes of your Kubernetes cluster (e.g. setting up MX records).

k8s_gateway is deployed on the IP choosen for ${BOOTSTRAP_METALLB_K8S_GATEWAY_ADDR}. Inorder to test DNS you can point your clients DNS to the ${BOOTSTRAP_METALLB_K8S_GATEWAY_ADDR} IP address and load https://hajimari.${BOOTSTRAP_CLOUDFLARE_DOMAIN} in your browser.

You can also try debugging with the command dig, e.g. dig @${BOOTSTRAP_METALLB_K8S_GATEWAY_ADDR} hajimari.${BOOTSTRAP_CLOUDFLARE_DOMAIN} and you should get a valid answer containing your ${BOOTSTRAP_METALLB_TRAEFIK_ADDR} IP address.

If your router (or Pi-Hole, Adguard Home or whatever) supports conditional DNS forwarding (also know as split-horizon DNS) you may have DNS requests for ${SECRET_DOMAIN} only point to the ${BOOTSTRAP_METALLB_K8S_GATEWAY_ADDR} IP address. This will ensure only DNS requests for ${SECRET_DOMAIN} will only get routed to your k8s_gateway service thus providing DNS resolution to your cluster applications/ingresses.

To access services from the outside world port forwarded 80 and 443 in your router to the ${BOOTSTRAP_METALLB_TRAEFIK_ADDR} IP, in a few moments head over to your browser and you should be able to access https://echo-server.${BOOTSTRAP_CLOUDFLARE_DOMAIN} from a device outside your LAN.

Now if nothing is working, that is expected. This is DNS after all!

🤖 Renovatebot

Renovatebot will scan your repository and offer PRs when it finds dependencies out of date. Common dependencies it will discover and update are Flux, Ansible Galaxy Roles, Terraform Providers, Kubernetes Helm Charts, Kubernetes Container Images, Pre-commit hooks updates, and more!

The base Renovate configuration provided in your repository can be view at .github/renovate.json5. If you notice this only runs on weekends and you can change the schedule to anything you want or simply remove it.

To enable Renovate on your repository, click the 'Configure' button over at their Github app page and choose your repository. Over time Renovate will create PRs for out-of-date dependencies it finds. Any merged PRs that are in the cluster directory Flux will deploy.

🪝 Github Webhook

Flux is pull-based by design meaning it will periodically check your git repository for changes, using a webhook you can enable Flux to update your cluster on git push. In order to configure Github to send push events from your repository to the Flux webhook receiver you will need two things:

  1. Webhook URL Your webhook receiver will be deployed on https://flux-receiver.${BOOTSTRAP_CLOUDFLARE_DOMAIN}/hook/:hookId. In order to find out your hook id you can run the following command:

    kubectl -n flux-system get receiver/github-receiver --kubeconfig=./provision/kubeconfig
# NAME              AGE    READY   STATUS
# github-receiver   6h8m   True    Receiver initialized with URL: /hook/12ebd1e363c641dc3c2e430ecf3cee2b3c7a5ac9e1234506f6f5f3ce1230e123

    So if my domain was k8s-at-home.com the full url would look like this:

    https://flux-receiver.k8s-at-home.com/hook/12ebd1e363c641dc3c2e430ecf3cee2b3c7a5ac9e1234506f6f5f3ce1230e123

  2. Webhook secret Your webhook secret can be found by decrypting the secret.sops.yaml using the following command:

    sops -d ./cluster/apps/flux-system/webhooks/github/secret.sops.yaml | yq .stringData.token

    Note: Don't forget to update the BOOTSTRAP_FLUX_GITHUB_WEBHOOK_SECRET variable in your .config.env file so it matches the generated secret if applicable

Now that you have the webhook url and secret, it's time to set everything up on the Github repository side. Navigate to the settings of your repository on Github, under "Settings/Webhooks" press the "Add webhook" button. Fill in the webhook url and your secret.

💾 Storage

Rancher's local-path-provisioner is a great start for storage but soon you might find you need more features like replicated block storage, or to connect to a NFS/SMB/iSCSI server. Check out the projects below to read up more on some storage solutions that might work for you.

👉 Troubleshooting

Our wiki (WIP, contributions welcome) is a good place to start troubleshooting issues. If that doesn't cover your issue, come join and say Hi in our Discord server by starting a new thread in the #kubernetes support channel.

You may also open a issue on this GitHub repo or open a discussion on GitHub.

❔ What's next

The world is your cluster, see below for important things you could work on adding.

Our Check out our wiki (WIP, contributions welcome) for more integrations!

🤝 Thanks

Big shout out to all the authors and contributors to the projects that we are using in this repository.

Community member @Whazor created this website as a creative way to search Helm Releases across GitHub. You may use it as a means to get ideas on how to configure an applications' Helm values.

Many people have shared their awesome repositories over at awesome-home-kubernetes.

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