Documentation

Quick note

This repo was templated from https://github.com/k8s-at-home/template-cluster-k3s and reduced/modified to match my own needs.

Cluster components

The following components will be installed in the k3s cluster by default.

• cert-manager - Operator to request SSL certificates and store them as Kubernetes resources
• 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 - local storage class provided by k3s
• nfs-subdir-external-provisioner - nfs default storage class provided by k3s (existing NFS server must be setup beforehand)
• metallb - bare metal load balancer
• reloader - restart pods when Kubernetes configmap or secret changes
• system-upgrade-controller - upgrade k3s
• traefik - ingress controller
• prometheus-kube-stack - prometheus operator with alertmanager
• blackbox-exporter - Exporter for prometheus to monitor HTTP/ICMP endpoints
• alertmanager-discord - Allows alerting to discord
• grafana - Webdashboard to visualize prometheus metrics
• home-assistant - Open source home automation platform
• tandoorrecipes - recipe manager that allows management of digital recipes
• pi-hole - a DNS sinkhole that protects your devices from unwanted content without installing any client-side software
• Argo CD - a declarative, GitOps continuous delivery tool for Kubernetes
• Miniflux - a minimalist and opinionated feed reader

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

Prerequisites

Systems

• One or more raspberry pis with a fresh install of Ubuntu Server 20.04.
• Some experience in debugging problems and a positive attitude ;)

Tools

Tools that needs to be installed on the local workstation.

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 (snap install task --classic)
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
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
|   ├── kube-system
|   ├── monitoring
│   ├── networking
│   └── system-upgrade
├── base
│   └── flux-system
├── core
│   ├── cert-manager
│   ├── metallb-system
│   ├── namespaces
|   ├── nfs-subdir-external-provisioner
│   └── system-upgrade
└── crds
    ├── traefik
    └── cert-manager

Installation

Setting up Age

Create a Age Private and Public key for encrypting and decrypting 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 in zshrc and source it

echo "export SOPS_AGE_KEY_FILE=~/.config/sops/age/keys.txt" >> ~/.zshrc
source ~/.zshrc

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

Configuration

The .config.env file contains necessary configuration files that are needed by Ansible and Flux.

1. Start filling out all the environment variables. All are required and read the comments they will explain further what is required.

2. Copy tmpl folder from k8s-at-home/template-cluster-k3s into the root directory of that repository

3. Verify the configuration is correct:

./configure.sh --verify

(If ssh test failed, make sure the ssh key is copied onto the servers)

4. 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

(Nodes are not security hardened by default, you can do this with dev-sec/ansible-collection-hardening or something similar.)

1. Install the deps by running task ansible:deps

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

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

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

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

6. Must be done manually for now. Open /boot/firmware/cmdline.txt and add cgroup_enable=memory cgroup_memory=1 to all raspberry pis. Reboot afterwards. https://rancher.com/docs/k3s/latest/en/advanced/#enabling-cgroups-for-raspbian-buster

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. Copy kubeconfig to ~/.kube/

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. 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    <none>                    4d20h   v1.21.5+k3s1
# k8s-2          Ready    <none>                    4d20h   v1.21.5+k3s1

5. Optionally label the workers so their role is displayed correctly

kubectl --kubeconfig=./provision/kubeconfig label node k8s-1 node-role.kubernetes.io/worker=''
kubectl --kubeconfig=./provision/kubeconfig label node k8s-2 node-role.kubernetes.io/worker=''
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
# k8s-2          Ready    worker                    4d20h   v1.21.5+k3s1

GitOps with Flux

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

4. Verify all the above files are encrypted with SOPS Commands for encryption / decryption:

# Decrypt secrets
sops --decrypt cluster/base/cluster-secrets.sops.yaml > cluster/base/cluster-secrets.yaml     
# Encrypt secrets 
sops --encrypt cluster/base/cluster-secrets.yaml > cluster/base/cluster-secrets.sops.yaml

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.

# Optional:
cp ./provision/kubeconfig ~/.kube/config && chmod 0600 ~/.kube/config

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/v1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1"
# unable to recognize "./cluster/base/flux-system": no matches for kind "HelmRepository" in version "source.toolkit.fluxcd.io/v1"

Workaround for error error GitRepository/flux-system.flux-system - Reconciler error auth secret error: Secret "flux-system" not found

export GITHUB_USER=<GITHUB_USER>
export GITHUB_TOKEN=<GITHUB_TOKEN>
flux bootstrap github --owner=$GITHUB_USER --repository=k3s-rpi-gitops --branch=main --path=./cluster/base --personal --private=false

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

Post installation

Upgrade kubernetes version

Update the channel spec of cluster/apps/system-upgrade-system-upgrade-controller/server-plan.yaml and cluster/apps/system-upgrade-system-upgrade-controller/agent-plan.yaml to the desired version.

Upgrade tigera-operator

1. Download the v<UPDATE_VERSION> operator manifest.

kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/<VERSION>/manifests/tigera-operator.yaml

2. Use the following command to initiate an upgrade.

kubectl replace -f tigera-operator.yaml

https://docs.tigera.io/calico/latest/operations/upgrading/kubernetes-upgrade#upgrading-an-installation-that-uses-the-operator

helpful commands

TODO

# Force reconciliation
flux reconcile helmrelease <HELMRELEASE> -n <NAMESPACE>
flux reconcile kustomization apps

# Get statuses of flux resources
flux get all
flux get helmrelease -A

# Follow flux logs
flux logs --level=error
flux logs --follow

# Monitor helm-controller
kubectl get pods -n flux-system
klf -n flux-system helm-controller-55896d6ccf-d9w8p
# klf -n flux-system $(kubectl get pods -n flux-system | grep -E 'helm-controller.*Running' | cut -d ' ' -f1)

# Fix message: "Helm upgrade failed: another operation (install/upgrade/rollback) is in progress"
helm delete <HELMRELEASE> -n <NAMESPACE>
flux reconcile helmrelease <HELMRELEASE> -n <NAMESPACE>

flux delete helmrelease <HELMRELEASE> -n <NAMESPACE>
flux reconcile source helm <HELMRELEASE>

# Fix error message (re-create kustomization): 
# ✗ Kustomization reconciliation failed: Secret/flux-system/cluster-secrets is SOPS encryted, configuring decryption is required for this secret to be reconciled
flux create kustomization cluster-secrets --source=flux-system --path=./cluster/base --prune=true --interval=10m --decryption-provider=sops --decryption-secret=sops-age