modify-ulimit.sh

if grep -q 32768 /etc/security/limits.conf; then
    	echo skip /etc/security/limits.conf;
else
	echo "*         hard    nofile      32768" | sudo tee -a /etc/security/limits.conf 
	echo "*         soft    nofile      32768" | sudo tee -a /etc/security/limits.conf
	echo "root      hard    nofile      65536" | sudo tee -a /etc/security/limits.conf
	echo "root      soft    nofile      65536" | sudo tee -a /etc/security/limits.conf
fi


if grep -q net.core.somaxconn /etc/sysctl.conf; then
	echo skip /etc/sysctl.conf;
else
	echo "net.core.somaxconn = 65536" | sudo tee -a /etc/sysctl.conf
fi

echo "reload settings";
sudo sysctl -p

Verify the new ulimit / files open settings

cat /proc/sys/fs/file-max && ulimit -n && ulimit -Hn

It's worth noting that ubuntu 16.04+ now has much higher defaults

815927
1024
65536

So you only need a single line for the soft limits

    echo "*         soft    nofile      32768" | sudo tee -a /etc/security/limits.conf