Pi-Cluster

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Parts

• 4 x Raspberry Pi 4 (4 and 8GB)
• 4 x SanDisk Extreme 64 GB microSDXC Memory Card
• 3 x SanDisk Ultra Fit USB 3.1 Flash-Laufwerk 256 GB
• 4 x GeeekPi Raspberry Pi 4 Luefter Kit, Aluminium Kuehlkoerper mit Luefter
• 4 x DeLock USB-Kabel - USB-C (M) bis 2 pin USB Header
• 1 x Hutschienen Netzteil 50W 5V 10A ; MeanWell, MDR-60-12
• 1 x Hutschiene / DIN-Schiene 30cm

graph TD;
    K[Kubectl] ---> M(main-node01);
    W01(worker-node01) ---> M;
    M --> W01;
    W02(worker-node02) ---> M;
    M --> W02;
    W03(worker-node03) ---> M;
    M --> W03;

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3D Print

• DIN Rail Stand KIT
• Raspberry Pi DIN Rail Mount

PI Setup

add cgroup_enable=memory to /boot/cmdline.txt

# configure timezone
dpkg-reconfigure tzdata
apt-get install ntp

Kubernetes Setup

# master
curl -sfL https://get.k3s.io | K3S_KUBECONFIG_MODE="644" \
INSTALL_K3S_EXEC=" --disable=traefik" sh -

# find the node token
cat /var/lib/rancher/k3s/server/node-token

# find client config
cat /etc/rancher/k3s/k3s.yaml

# agent
curl -sfL https://get.k3s.io | K3S_URL=https://10.0.1.100:6443 K3S_TOKEN=<token> sh -

Client Setup

# copy client config from master
scp [email protected]:/etc/rancher/k3s/k3s.yaml ~/.kube/config

# replace master ip address
sed -i 's/127.0.0.1/10.0.1.100/' ~/.kube/config

# no pods on master node
kubectl taint node main-node01 kubernetes=master:NoSchedule

Cluster Upgrade

k3s release versions

kubectl apply -f https://github.com/rancher/system-upgrade-controller/releases/latest/download/system-upgrade-controller.yaml
kubectl apply -f k3s-system-upgrade.yaml

Ingress (nginx)

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm install nginx-ingress ingress-nginx/ingress-nginx --namespace kube-system \
--set controller.ingressClass=nginx --set prometheus.create=true

Cet-Manager (letsencrypt)

kubectl create ns cert-manager
helm repo add jetstack https://charts.jetstack.io
helm install cert-manager jetstack/cert-manager --namespace cert-manager --set installCRDs=true

cat letsencrypt-prod.yaml

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    email: [email protected]
    disableAccountKeyGeneration: false
    server: https://acme-v02.api.letsencrypt.org/directory
    privateKeySecretRef:
      name: letsencrypt-prod
    solvers:
    - http01:
        ingress:
          class: nginx

kubectl apply -n cert-manager -f letsencrypt-prod.yaml

NFS Server

# install NFS on 10.0.1.100 first and export /mnt/data
apt install nfs-kernel-server
cat /etc/exports
/mnt/data  10.0.1.0/24(rw,sync,no_subtree_check)
exportfs

kubectl create ns nfs-subdir-external-provisioner
helm install nfs-subdir-external-provisioner --namespace nfs-subdir-external-provisioner --create-namespace \
nfs-subdir-external-provisioner/nfs-subdir-external-provisioner \
--set nfs.server=10.0.1.100 --set nfs.path=/mnt/data

cat pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  namespace: nfs-subdir-external-provisioner
  name: example-pvc-data
spec:
  accessModes:
    - ReadWriteMany
  # - ReadWriteOnce
  storageClassName: nfs-client
  #storageClassName: local-path
  resources:
    requests:
      storage: 1Gi

Docker Registry

kubectl create ns docker-registry
helm repo add twuni https://helm.twun.io
helm install docker-registry twuni/docker-registry -f values.yaml --namespace docker-registry

cat values.yaml
replicaCount: 1

image:
  repository: registry
  tag: 2.7.1
  pullPolicy: IfNotPresent
service:
  name: registry
  type: ClusterIP
  port: 5000
  annotations: {}
ingress:
  enabled: false
persistence:
  accessMode: 'ReadWriteOnce'
  enabled: true
  size: 10Gi
  storageClass: 'nfs-client'

storage: filesystem

secrets:
  htpasswd: "" # docker run --entrypoint htpasswd registry:2 -Bbn user password > ./htpasswd

configData:
  version: 0.1
  log:
    fields:
      service: registry
  storage:
    cache:
      blobdescriptor: inmemory
  data:
    body-size: "0"
  http:
    addr: :5000
    headers:
      X-Content-Type-Options: [nosniff]
  health:
    storagedriver:
      enabled: true
      interval: 10s
      threshold: 3

securityContext:
  enabled: true
  runAsUser: 1000
  fsGroup: 1000

cat ingress.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    acme.cert-manager.io/http01-edit-in-place: "true"
    cert-manager.io/cluster-issuer: letsencrypt-prod
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/proxy-body-size: 1024m
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
    nginx.org/client-max-body-size: 1024m
  name: registry-ingress
  namespace: docker-registry
spec:
  rules:
  - host: registry.example.com
    http:
      paths:
      - pathType: Prefix
        path: /
        backend:
          service:
            name: docker-registry
            port:
              number: 5000
  tls:
  - hosts:
    - registry.example.com
    secretName: registry-example-com-tls

Every node in the cluster need this, to login to your docker registry

cat /etc/rancher/k3s/registries.yaml

mirrors:
  registry.tino.sh:
    endpoint:
      - "https://registry.example.com"
configs:
  "registry.tino.sh":
    auth:
      username: user # this is the registry username
      password: p@$$s0rd # this is the registry password

logs

# logs can be found in /var/log/containers on each host

delete old images on worker node

k3s crictl rmi --prune

debug pod

build image

cd debug
docker build -t debug .
docker tag debug registry.tino.sh/debug
docker push registry.tino.sh/debug

start debugging container

debug-running-pod

kubectl run debug-pod --image=registry.tino.sh/debug --restart=Never -- sleep 3600
kubectl exec -it debug-pod -- bash
kubectl delete pod debug-pod

start debugging with ephemeral container

kubectl debug pod-name-59987fcd5b-sp6x2 -it --image=registry.tino.sh/debug --share-processes --copy-to=debug-pod -- bash
kubectl delete pod debug-pod

UP^