• prepare Hosts [all nodes]
  • disable swap
    swapoff -a
• add cluster DNS to /etc/hosts
  • e.g. onprem.cloud
    echo “127.0.0.1 onprem.cloud” >> /etc/hosts

apt install -y curl gpg
# edit /etc/sysctl.conf
#   net.ipv4.ip_forward=1
#   net.bridge.bridge-nf-call-iptables=1
sysctl -w net.ipv4.ip_forward=1
sysctl -w net.bridge.bridge-nf-call-iptables=1
# edit /etc/modules
#   br_netfilter
modprobe br_netfilter
export KUBECONFIG=/etc/kubernetes/admin.conf
echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> /root/.bashrc

• install Container Runtime CRI-O (https://cri-o.io/) [all nodes]

export OS=Debian_11
export VERSION=1.25
echo "deb https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/ /" > /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list
echo "deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$VERSION/$OS/ /" > /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:$VERSION.list

curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$VERSION/$OS/Release.key | apt-key add -
curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/Release.key | apt-key add -

apt update
apt install -y cri-o cri-o-runc
systemctl enable crio.service
systemctl start crio.service

• install K8s (https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/) [all nodes]

apt install -y apt-transport-https ca-certificates curl
mkdir /etc/apt/keyrings
curl -fsSL https://packages.cloud.google.com/apt/doc/apt-key.gpg | gpg --dearmor | dd status=none of=/etc/apt/keyrings/kubernetes-archive-keyring.gpg
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | tee /etc/apt/sources.list.d/kubernetes.list
apt update
apt install -y kubelet kubeadm kubectl
apt-mark hold kubelet kubeadm kubectl

• install CNI Cillium (https://docs.cilium.io/en/stable/gettingstarted/k8s-install-default/) [all nodes]

CILIUM_CLI_VERSION=$(curl -s https://raw.githubusercontent.com/cilium/cilium-cli/master/stable.txt)
CLI_ARCH=amd64
if [ "$(uname -m)" = "aarch64" ]; then CLI_ARCH=arm64; fi
curl -L --fail --remote-name-all https://github.com/cilium/cilium-cli/releases/download/${CILIUM_CLI_VERSION}/cilium-linux-${CLI_ARCH}.tar.gz{,.sha256sum}
sha256sum --check cilium-linux-${CLI_ARCH}.tar.gz.sha256sum
tar xzvfC cilium-linux-${CLI_ARCH}.tar.gz /usr/local/bin
rm cilium-linux-${CLI_ARCH}.tar.gz{,.sha256sum}

Create Cluster [control plane]

kubeadm init --control-plane-endpoint=onprem.cloud --v=5 --pod-network-cidr=10.244.0.0/16
# wait for node to get 'ready'
watch --color 'kubectl get nodes'

cilium install
cilium status

• Join Nodes [worker nodes]

kubeadm token create --print-join-command

• reset K8s Node

kubeadm reset

• expose K8s Port
  

iptables -t nat -A PREROUTING -d 10.10.10.172/24 -i eno1 -p tcp --dport 6443 -j DNAT --to-destination 192.168.122.234:6443
iptables -I FORWARD -p tcp -d 192.168.122.234/24 --dport 6443 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT

• test Cluster

kubectl create namespace test
kubectl config set-context --current --namespace=test
kubectl create deployment whoami --image=traefik/whoami:latest
#kubectl expose deployment whoami --name whoami-service --port 80 --target-port=30080 --type NodePort
kubectl create service nodeport whoami --node-port=30080 --tcp=80:80

https://kubernetes.io/de/docs/reference/kubectl/cheatsheet/