Multipath TCP kernel on DigitalOcean droplet (Ubuntu 14.04)

gistfile1.txt

(all instruction need root permission)

0. Create a droplet with Ubuntu 14.04 image

1. wget -q -O - http://multipath-tcp.org/mptcp.gpg.key | sudo apt-key add - 

2. vim /etc/apt/sources.list.d/mptcp.list , add line:
  deb http://multipath-tcp.org/repos/apt/debian trusty main

3. apt-get update && apt-get install linux-mptcp

4. vim /etc/init.d/droplet-kernel
### BEGIN INIT INFO
# Provides:          droplet-kernel
# Required-Start:
# Required-Stop:
# Should-Start:      glibc
# Default-Start:     S
# Default-Stop:      6
# X-Interactive:     true
# Short-Description: Run kexec on DigitalOcean droplet
# Description:       Runs kexec on a DigitalOcean droplet to boot a custom kernel
### END INIT INFO

PATH=/sbin:/bin:/usr/sbin:/usr/bin

. /lib/lsb/init-functions

test -r /etc/default/droplet-kernel && . /etc/default/droplet-kernel

do_stop() {
        # Don't do anything if kexec-tools are not installed
        # or droplet-kernel is not enabled in defaults file.
        test -x /sbin/kexec || exit 0
        test "$ENABLED" = "true" || exit 0

        # Check 'kexeced' kernel cmdline is present otherwise droplet
        # wasn't booted with a custom kernel via kexec.
        if grep -q ' kexeced$' /proc/cmdline; then

                # Remove 'kexeced' cmdline arguement so that when the droplet
                # is rebooted it will load and boot the custom kernel again.
                cat /proc/cmdline | sed 's/ kexeced$//' > /root/cmdline
                mount --bind -n -o ro /root/cmdline /proc/cmdline >/dev/null
                kexec -u

                log_action_msg "Removed 'kexeced' kernel cmdline from droplet"
        else
                log_action_msg "Droplet was not booted with custom kernel"
        fi
}

do_start() {
        # Don't do anything if kexec-tools are not installed
        # or droplet-kernel is not enabled in defaults file.
        test -x /sbin/kexec || exit 0
        test "$ENABLED" = "true" || exit 0

        do_status

        # Check 'kexeced' kernel cmdline is not present.
        # If it is, the droplet has already booted with kexec. This helps
        # prevent loops.
        if grep -qv ' kexeced$' /proc/cmdline; then

                # Give the option to abort booting the droplet using kexec.
                export KEXEC_ABORT=false
                trap "export KEXEC_ABORT=true" 2
                log_begin_msg "Press Ctrl+C to abort booting droplet with custom kernel"
                sleep 10
                trap - 2
                log_end_msg 0

                REAL_APPEND="$APPEND"
                test -z "$REAL_APPEND" && REAL_APPEND="`cat /proc/cmdline`"

                if [ "$KEXEC_ABORT" = "false" ]; then
                        log_action_begin_msg "Loading new kernel in to droplet memory"
                        if [ -z "$INITRD" ]; then
                                kexec --load "$KERNEL_IMAGE" --append="$REAL_APPEND kexeced"
                        else
                                kexec --load "$KERNEL_IMAGE" --initrd="$INITRD" --append="$REAL_APPEND kexeced"
                        fi
                        log_action_end_msg $?

                        log_action_begin_msg "Attempting to run droplet with custom kernel"
                        kexec -e
                        log_action_end_msg $?
                fi
        fi
}

do_status() {
        if [ "$ENABLED" != "true" ]; then
                log_action_msg "Custom droplet kernel is NOT enabled"
                exit 0
        fi

        log_action_msg "Custom droplet kernel is enabled"

        if grep -q 'kexeced$' /proc/cmdline; then
                log_action_msg "Droplet was booted with a custom kernel"
        else
                log_action_msg "Droplet was NOT booted with a custom kernel"
        fi
}

case "$1" in
  start)
        do_start
        ;;
  restart|reload|force-reload)
        echo "Error: argument '$1' not supported" >&2
        exit 3
        ;;
  stop)
        do_stop
        ;;
  status)
        do_status
        ;;
  *)
        echo "Usage: $0 {start|stop|status}" >&2
        exit 3
        ;;
esac
exit 0

5. chmod 755 /etc/init.d/droplet-kernel

6. vim /etc/default/droplet-kernel
# Defaults for droplet-kernel initscript
# sourced by /etc/init.d/droplet-kernel

# Load a custom kernel for the droplet (true/false)
ENABLED=true

# Kernel and initrd image.
# If no initrd image is needed, leave blank.
KERNEL_IMAGE="/vmlinuz"
INITRD="/initrd.img"

# If empty, use current /proc/cmdline
APPEND=""

7. update-rc.d droplet-kernel defaults

8. sync;sync;sync;sync;reboot

9. After reboot, login and check if MPTCP is enabled by: 
kernel.osrelease = 3.18.20-90-mptcp
net.mptcp.mptcp_checksum = 1
net.mptcp.mptcp_debug = 0
net.mptcp.mptcp_enabled = 1
net.mptcp.mptcp_path_manager = fullmesh
net.mptcp.mptcp_scheduler = default
net.mptcp.mptcp_syn_retries = 3

10. You're all set!