cluster-k3s

Template for creating a k3s cluster with k3sup, Flux and SOPS

This template will bootstrap the nodes you want with the following components

• k3s
• flux
• metallb
• flannel

:memo:  Prerequisites

:computer:  Nodes

Bare metal or VMs with a modern operating system like Ubuntu, Debian or CentOS.

:wrench:  Tools

Tool	Purpose	Required
k3sup	Tool to install k3s on your nodes	✅
flux	Operator that manages your k8s cluster based on your Git repository	✅
kustomize	Template-free way to customize application configuration	✅
SOPS	Encrypts k8s secrets with GnuPG	✅
GnuPG	Encrypts and signs your data	✅
pinentry	Allows GnuPG to read passphrases and PIN numbers	✅
direnv	Exports env vars based on present working directory	❌
pre-commit	Keeps formatting consistency across your files	❌

:rocket:  Installation

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

:key:  Setting up GnuPG keys

1. Create a Personal GPG Key, password protected, and export the fingerprint

export GPG_TTY=$(tty)
export PERONAL_KEY_NAME="First name Last name (location) <email>"

gpg --batch --full-generate-key <<EOF
Key-Type: 1
Key-Length: 4096
Subkey-Type: 1
Subkey-Length: 4096
Expire-Date: 0
Name-Real: ${PERONAL_KEY_NAME}
EOF

gpg --list-secret-keys "${PERONAL_KEY_NAME}"
# pub   rsa4096 2021-03-11 [SC]
#       772154FFF783DE317KLCA0EC77149AC618D75581
# uid           [ultimate] k8s@home (Macbook) <k8s-at-home@gmail.com>
# sub   rsa4096 2021-03-11 [E]

export PERSONAL_KEY_FP=772154FFF783DE317KLCA0EC77149AC618D75581

2. Create a Flux GPG Key and export the fingerprint

export GPG_TTY=$(tty)
export FLUX_KEY_NAME="Cluster name (Flux) <email>"

gpg --batch --full-generate-key <<EOF
%no-protection
Key-Type: 1
Key-Length: 4096
Subkey-Type: 1
Subkey-Length: 4096
Expire-Date: 0
Name-Real: ${KEY_NAME}
EOF

gpg --list-secret-keys "${FLUX_KEY_NAME}"
# pub   rsa4096 2021-03-11 [SC]
#       AB675CE4CC64251G3S9AE1DAA88ARRTY2C009E2D
# uid           [ultimate] Home cluster (Flux) <k8s-at-home@gmail.com>
# sub   rsa4096 2021-03-11 [E]

export FLUX_KEY_FP=AB675CE4CC64251G3S9AE1DAA88ARRTY2C009E2D

:sailboat:  Installing k3s with k3sup

1. Ensure you are able to SSH into you nodes with using your private ssh key. This is how k3sup is able to connect to your remote node.

2. Install the master node

k3sup install \
    --host=169.254.1.1 \
    --user=k8s-at-home \
    --k3s-version=v1.20.5+k3s1 \
    --k3s-extra-args="--disable servicelb --disable traefik"

3. Join a worker node(s) (optional)

k3sup join \
    --host=169.254.1.2 \
    --server-host=169.254.1.1 \
    --k3s-version=v1.20.5+k3s1 \
    --user=k8s-at-home

4. Verify nodes are online

kubectl --kubeconfig=./kubeconfig get nodes
# NAME           STATUS   ROLES                       AGE     VERSION
# k8s-master-a   Ready    control-plane,master      4d14h   v1.20.5+k3s1
# k8s-worker-a   Ready    worker                    4d14h   v1.20.5+k3s1

GitOps with Flux

1. Pre-create the namespace

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

1. Add the Flux GPG key in-order for Flux to decrypt SOPS secrets

gpg --export-secret-keys --armor "${FLUX_KEY_FP}" |
kubectl --kubeconfig=./kubeconfig create secret generic sops-gpg \
    --namespace=flux-system \
    --from-file=sops.asc=/dev/stdin

3. Update files using envsubst or by updating them manually

export BOOTSTRAP_GITHUB_REPOSITORY="k8s-at-home/home-cluster"
export BOOTSTRAP_DOMAIN="k8s-at-home.com"
export BOOTSTRAP_METALLB_LB_RANGE="169.254.1.10-169.254.1.20"

envsubst < ./.sops.yaml
envsubst < ./cluster/cluster-secrets.yaml
envsubst < ./cluster/cluster-settings.yaml
envsubst < ./cluster/base/flux-system/gotk-sync.yaml

4. Verify all the above files have the correct information present

5. Encrypt cluster-settings.yaml with SOPS

sops --encrypt --in-place ./cluster/base/cluster-secrets.yaml

6. Verify this file is encrypted with SOPS

7. Push you changes to git

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

8. Install Flux

kubectl --kubeconfig=./kubeconfig --kustomize=./cluster/base/flux-system

Post installation

pre-commit

pre-commit install-hooks

:handshake:  Thanks

A lot of inspiration for my cluster came from the people that have shared their clusters over at awesome-home-kubernetes