k8s_install.sh

#!/bin/bash
# kubeadm installation instructions as on
# https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

yum install -y  yum-utils
yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo

yum install containerd.io

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF

# Set SELinux in permissive mode (effectively disabling it)
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

# disable swap (assuming that the name is /dev/centos/swap
sed -i 's/^LABEL=SWAP-xvdb1/#LABEL=SWAP-xvdb1/' /etc/fstab
swapoff LABEL=SWAP-xvdb1

yum install -y tc yum-utils kubelet kubeadm kubectl --disableexcludes=kubernetes

systemctl enable --now kubelet

cat <<EOF | tee /etc/modules-load.d/containerd.conf
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter

# Set iptables bridging
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

mkdir -p /etc/containerd
containerd config default | tee /etc/containerd/config.toml
systemctl restart containerd
systemctl enable containerd