install_k8s_worker.sh

########################################
# K8s: Version 1.28 
# Linux: Ubuntu 22.04
# 
# This script is Installation Kubernetes on Ubuntu with containerd 
# as the container runtime and flannel as the CNI plugin for a worker node.
# After the script runs successfully the node can then run the kubeadm join 
# command that the master node outputs after kubeadm init
# or after this command:
# sudo kubeadm token create --print-join-command
########################################
# This script assumes swap is disabled #
# sudo swapoff -a
# sudo sed -i '/ swap / s/^/#/' /etc/fstab

# Forwarding IPv4 and letting iptables see bridged traffic
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

sudo sysctl --system

sudo apt-get update
sudo apt-get install -y \
    apt-transport-https \
    ca-certificates \
    curl \
    gnupg \
    lsb-release

# Install containerd
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
  $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

sudo apt-get update
sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
sudo mkdir -p /etc/containerd
sudo bash -c 'containerd config default > /etc/containerd/config.toml'
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml
sudo systemctl enable containerd
sudo systemctl restart containerd

# Install kubeadm, kubelet and kubectl
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
# This overwrites any existing configuration in /etc/apt/sources.list.d/kubernetes.list
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

sudo apt-get update
sudo apt-get install -y kubelet=1.28.0-1.1 kubeadm=1.28.0-1.1 kubectl=1.28.0-1.1
sudo apt-mark hold kubelet kubeadm kubectl

sudo systemctl start kubelet
sudo systemctl enable kubelet