GitOps for tbrnt k3s hosting

Repo structure

• Each subdirectory is a namespace
• _apps is the meta directory for Argo CD apps
• Another private repo contains stuff in a more approachable format, f.e. for dealing with updating sealed-secrets: gitops-tbrnt-private
• _tests contains some Open Policy Agent rego files which are used in the Drone CI pipeline to validate configuration.

Usage

Argo CD

Access

Either

sudo -E kubefwd svc -n argocd and then https://argocd-server/

or

kubectl port-forward svc/argocd-server -n argocd 8080:443 and then https://localhost:8080/

CLI

• argocd login argocd-server
• argocd app list
• argocd app sync <name>

Kubeseal (Sealed Secrets)

See README of apps. Basically:

kubeseal --controller-namespace sealed-secrets -o yaml -n MYNS < ../../gitops-tbrnt-private/MYNS/MYSECRET.yaml > MYSECRET-secret.yaml

Bootstrap GitOps

After installing k3s, do:

# install Argo CD
kubectl create ns argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
kubectl get pods -n argocd -l app.kubernetes.io/name=argocd-server -o name | cut -d'/' -f 2
argocd login argocd-server

# Restore Sealed Secrets secret key
kubectl create ns sealed-secrets
kubectl apply -f ../gitops-tbrnt-private/sealed-secrets/master-key.yaml

# Instantiate Argo Root App
kubectl apply -f _apps/apps.yaml

# Let Argo CD do it's job
argocd app sync apps
argocd app sync sealed-secrets
argocd app sync -l app.kubernetes.io/instance=apps

TODO:

• Restore PVCs via K8up

k3s on Alpine

Installing: Alpine

Basically follow the Alpine wiki.

Then install prerequisites and some essential packages:

apk add \
  vim \
  iptables \
  wireguard-virt \
  bash \
  curl

Needs community repo enabled in /etc/apk/repositories.

Tweak Sysctl in /etc/sysctl.conf:

fs.inotify.max_user_instances = 8192
fs.inotify.max_user_watches = 524288

Add rshared mount option to root filesystem for node-exporter to work correctly.

Installing: k3s

Via k3sup:

k3sup install \
  --ip=185.95.218.11 \
  --user=root \
  --local-path=~/.kube/config_knurrli2 \
  --sudo=false \
  --k3s-extra-args='--tls-san knurrli.tobrunet.ch --cluster-cidr 10.44.0.0/16 --flannel-backend wireguard'

Helpful infos

Paths

• Volumes: /var/lib/rancher/k3s/storage/
• Config: /etc/rancher/k3s/
• Manifests: /var/lib/rancher/k3s/server/manifests/

Links

• https://rancher.com/docs/k3s/latest/en/advanced/#additional-preparation-for-alpine-linux-setup
• https://github.com/rancher/k3s/issues/660

Configure Wireguard

/etc/network/interfaces

auto wg0
iface wg0 inet static
    address 10.42.42.16
    netmask 255.255.255.0
    pre-up ip link add dev wg0 type wireguard
    pre-up wg setconf wg0 /etc/wireguard/wg0.conf
    post-up ip route add 10.42.42.0/24 dev wg0
    post-down ip link delete dev wg0

• https://wiki.alpinelinux.org/wiki/Configure_a_Wireguard_interface_(wg)