Bash script to automatically install and configure container runtime, cni plugins etc

k8s-prepare-node.sh

#!/bin/bash
set -eou pipefail

#========== Step 1: Disable Swap ============
echo "Disabling Swap......."
sudo swapoff -a
sudo sed -i '/^[^#]/ s/\(^.*swap.*$\)/#\1/' /etc/fstab
free -h
echo ""

#========= Step 2: Forward IPv4 network and let iptables to see bridged traffic =============
echo "Forwarding IPv4 network and enabling bridged traffic....."
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter

# sysctl params required by setup, params persist across reboots
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

# Apply sysctl params without reboot
sudo sysctl --system
echo ""

# ======== Step 3: Install containerd ====================
echo "Installing containerd......"
wget https://github.com/containerd/containerd/releases/download/v1.6.6/containerd-1.6.6-linux-amd64.tar.gz
tar Cxzvf /usr/local containerd-1.6.6-linux-amd64.tar.gz

# automatically start containerd using systemd
wget https://raw.githubusercontent.com/containerd/containerd/main/containerd.service
sudo mkdir -p /usr/local/lib/systemd/system/
sudo mv ./containerd.service /usr/local/lib/systemd/system/
systemctl daemon-reload
systemctl enable --now containerd

echo ""

# ================ Step 4: Install runc ==============
echo "Installing runc.................."
wget https://github.com/opencontainers/runc/releases/download/v1.1.3/runc.amd64
sudo install -m 755 runc.amd64 /usr/local/sbin/runc
echo ""

# ============== Step 5: Install CNI Plugins ========
echo "Installing CNI Plugins.......... "
wget https://github.com/containernetworking/plugins/releases/download/v1.1.1/cni-plugins-linux-amd64-v1.1.1.tgz
mkdir -p /opt/cni/bin
tar Cxzvf /opt/cni/bin cni-plugins-linux-amd64-v1.1.1.tgz
echo ""

# ============ Step 5: Generate config.toml for cont
echo "Configuring containerd........"
sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml
echo ""

# ========= Step 6: Use cgroup v2 ===============
echo "Configuring the systemd cgroup driver"
sudo sed -i 's/SystemdCgroup.*/SystemdCgroup = true/g' /etc/containerd/config.toml
sudo systemctl restart containerd

# =========== Step 7: Install kubeadm,kubelet,kubectl
sudo apt update
sudo apt install -y apt-transport-https ca-certificates curl
sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg
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
sudo apt update
sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl