kubernetes-the-hard-way/vagrant/ubuntu/setup-kernel.sh

#!/bin/bash
#
# Sets up the kernel with the requirements for running Kubernetes
set -e

# Add br_netfilter kernel module
cat <<EOF >> /etc/modules
ip_vs
ip_vs_rr
ip_vs_wrr
ip_vs_sh
br_netfilter
nf_conntrack
EOF
systemctl restart systemd-modules-load.service

# Set network tunables
cat <<EOF >> /etc/sysctl.d/10-kubernetes.conf
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
net.bridge.bridge-nf-call-iptables=1
net.ipv4.ip_forward=1
EOF

sysctl --system