#!/bin/bash

function do_update
{
    cp /etc/sysctl.conf /etc/sysctl.conf.`date +%F-%H%M%S`
    echo "kernel.keys.maxkeys=2000" >> /etc/sysctl.conf
    echo "fs.inotify.max_queued_events=1048576" >> /etc/sysctl.conf
    echo "fs.inotify.max_user_instances=1048576" >> /etc/sysctl.conf
    echo "fs.inotify.max_user_watches=1048576" >> /etc/sysctl.conf
    echo "vm.max_map_count=262144" >> /etc/sysctl.conf
    echo "net.ipv4.neigh.default.gc_thresh3=8192" >> /etc/sysctl.conf

    cp /etc/security/limits.conf /etc/security/limits.conf.`date +%F-%H%M%S`
    echo "*       soft    nofile  1048576" >> /etc/security/limits.conf
    echo "*       hard    nofile  1048576" >> /etc/security/limits.conf
    echo "root    soft    nofile  1048576" >> /etc/security/limits.conf
    echo "root    hard    nofile  1048576" >> /etc/security/limits.conf
    echo "*       soft    memlock unlimited" >> /etc/security/limits.conf
    echo "*       hard    memlock unlimited" >> /etc/security/limits.conf    
}

echo "This script enables runing lots of containers on a single host."
echo "Note it must be run as root, sudo is insufficient."
echo "Do you wish to proceed?"
select yn in "Yes" "No"; do
    case $yn in
        Yes ) do_update; break;;
        No ) exit;;
    esac
done
sysctl -p