k3s cluster backed by Flux

Overview

• Introduction
• Prerequisites
• Repository structure
• Lets go!
• Post installation
• Thanks

Introduction

The following components are installed by default. They are only included to get a minimum viable cluster up and running.

• cert-manager - SSL certificates - with Cloudflare DNS challenge
• calico - CNI (container network interface)
• flux - GitOps tool for deploying manifests from the cluster directory
• hajimari - start page with ingress discovery
• 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
• system-upgrade-controller - upgrade k3s
• traefik - ingress controller

📝  Prerequisites

💻  Systems

• One or more nodes with a fresh install of Ubuntu Server 20.04. These nodes can be bare metal or VMs.
• A Cloudflare account with a domain, this will be managed by Terraform.
• Some experience in debugging problems and a positive attitude ;)

🔧  Tools

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

Required

| Tool | Purpose | |----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------- | 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 | | 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
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 will check to make sure you are not by accident committing your secrets un-encrypted.

After pre-commit is installed on your machine run:

pre-commit install-hooks

📂  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
│   ├── networking
│   └── system-upgrade
├── base
│   └── flux-system
├── core
│   ├── cert-manager
│   ├── metallb-system
│   ├── namespaces
│   └── system-upgrade
└── crds
    └── cert-manager

🚀  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.

📄  Configuration

📍 The .config.env file contains necessary configuration files that are 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 and read the comments they will explain further what is required.

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 something similar.

1. Ensure you are able to SSH into you nodes from your workstation with using your private ssh key. This is how Ansible is able to connect to your remote nodes.

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:adhoc:ping

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

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

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

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

🔹  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.sops.yaml will be usable anywhere in your YAML manifests under ./cluster

4. Verify all the above 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

🎉 Congratulations you have a Kubernetes cluster managed by Flux, your Git repository is driving the state of your cluster.

☁️  Configure Cloudflare DNS with Terraform

📍 Review the Terraform scripts under ./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. Ideally you can update the terraform script to manage DNS for all records if you so choose to.

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

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

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

If Terraform was ran successfully head over to your browser and you should be able to access https://hajimari.${BOOTSTRAP_CLOUDFLARE_DOMAIN}

📣  Post installation

👉  Troubleshooting

Our wiki is a good place to start troubleshooting issues. If that doesn't cover your issue, start a new thread in the #support channel on our Discord.

🤖  Integrations

Our Check out our wiki for more integrations!

❔  What's next

The world is your cluster, try installing another application or if you have a NAS and want storage back by that check out the helm charts for democratic-csi, csi-driver-nfs or nfs-subdir-external-provisioner.

If you plan on exposing your ingress to the world from your home. Checkout our rough guide to run a k8s CronJob to update DDNS.

🤝  Thanks

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