Cluster: Worker Node

Set permanent DNS-Servers

# Edit the resolv.conf file
sudo nano /etc/resolv.conf

#File: /etc/resolv.conf
nameserver 10.100.1.1
nameserver 192.168.1.1

# Update apt package index
sudo apt update

# Install resolvconf
sudo apt install resolvconf

# Request the status from service resolvconf
sudo systemctl status resolvconf.service

# Edit the head file
sudo nano /etc/resolvconf/resolv.conf.d/head

#File /etc/resolvconf/resolv.conf.d/head
nameserver 10.100.1.1
nameserver 192.168.1.1

# Start the service resolvconf again
sudo systemctl start resolvconf.service

# Try to ping google.ch
ping google.ch

# Try to make an nslookup command on google.ch
nslookup google.ch

Letting iptables see bridged traffic

# Load the br_netfilter module
sudo modprobe br_netfilter

# Make sure, that the br_netfilter module is loaded
lsmod | grep br_netfilter

# As a requirement for your Linux Node's iptables to correctly see bridged traffic
# you should ensure net.bridge.bridge-nf-call-iptables is set to 1

# Edit the sysctl file
sudo nano /etc/sysctl.conf

#File: /etc/sysctl.conf
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

# Request the entry
sudo sysctl --system

Disable the swap partition

# Edit the fstab file
sudo nano /etc/fstab

# Disable the swap-partition
sudo swapoff -a

Install Docker-Engine (Ubuntu)

# Update the apt package index 
sudo apt-get update

# Install packages to allow apt to use a repository over HTTPS:
sudo apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    gnupg \
    lsb-release

# Add Docker’s official GPG key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

# Set up the stable repository (x86_64 / amd64)
echo \
  "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

# Update the apt package index
sudo apt-get update

#Install the latest version of Docker Engine and containerd
sudo apt-get install docker-ce docker-ce-cli containerd.io

# Configure the Docker daemon, in particular to use systemd for the management of the container’s cgroups
sudo mkdir /etc/docker
cat <<EOF | sudo tee /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF

# Restart Docker and enable on boot
sudo systemctl enable docker
sudo systemctl daemon-reload
sudo systemctl restart docker

Installing kubeadm, kubelet, kubectl

# Update the apt package index 
sudo apt-get update

# Install packages needed to use the Kubernetes apt repository
sudo apt-get install -y apt-transport-https ca-certificates curl

# Download the Google Cloud public signing key
sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg

# Add the Kubernetes apt repository
echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update apt package index
sudo apt-get update

# Install kubelet, kubeadm, kubectl
sudo apt-get install -y kubelet kubeadm kubectl

# Pin their version
sudo apt-mark hold kubelet kubeadm kubectl

Join a cluster

# Join any number of worker nodes 
kubeadm join 10.100.1.155:6443 --token s5z4yi.dv8df1bhsr5ihnwn \
        --discovery-token-ca-cert-hash sha256:0c9e75101944003b9bf2d4a216df7a69d109f5aecbc6b02bb85828145e0ff094