AWS EC2: setup high number of outgoing (persistent) connections from single instance (4 ENI) - 4 million connections

ip-setup-eni.sh

#!/bin/bash

# Juan Pablo and Zbyszek Zolkiewski (at) ProcessOne 2015-2018
#
# This script configures additional 3 ENI (+1 aliased eth0) on AWS ec2
# Following setup allow to generate around 4 milion outgoing connections from single instance
# If one need more, you need to add additional ENI and allocate max 15 IP per ENI (AWS limit)

# RPS:
# echo ff > /sys/class/net/eth0/queues/rx-0/rps_cpus

echo "<<<< Adding IP aliases on eth0 >>>>"
i=0
MAC_ADDR=$(ifconfig eth0 | sed -n 's/.*HWaddr \([a-f0-9:]*\).*/\1/p')
IP=($(curl http://169.254.169.254/latest/meta-data/network/interfaces/macs/$MAC_ADDR/local-ipv4s -s))
for ip in ${IP[@]:1}; do
    echo "Adding IP: $ip (eth0)"
    ip addr add dev eth0 $ip/24
    i=$(expr $i + 1)
done
echo "--> $i IP added on eth0"

# add 3 new NIC:
for eth in {1..3}; do
  iseth=$(ip link show eth$eth|grep -c UP)
  if [ ! $iseth ]; then
    echo "No eth$eth!"
    exit
  fi

  echo "<<<< Adding IP aliases on eth$eth >>>>"
  i=0
  # get default route
  droute=$(ip route|grep "default via" | awk '{print $3}')

  rnum=$(expr $eth + 1)
  # add this table
  echo "$rnum eth$eth"_"rt" >> /etc/iproute2/rt_tables

  ip route add default via $droute dev eth$eth table eth$eth"_"rt

  MAC_ADDR=$(ifconfig eth$eth | sed -n 's/.*HWaddr \([a-f0-9:]*\).*/\1/p')
  IP=($(curl http://169.254.169.254/latest/meta-data/network/interfaces/macs/$MAC_ADDR/local-ipv4s -s))
  for ip in ${IP[@]:0}; do
      echo "Adding IP: $ip (eth$eth)"
      ip addr add dev eth$eth $ip/24
      ip rule add from $ip lookup eth$eth"_"rt prio 1000
      i=$(expr $i + 1)
  done
  echo "--> $i IP added on eth$eth"
done