DokuWiki » Infrastructure » Operating System » CentOS 6

h1. Install n2n-Supernode

h2. Requirements

To install n2n you will need the following:

* a installed and supported operating system (e.g. CentOS 6.x)

* root-access

* EPEL repository

* a fast internet connection

h2. Preliminary note

most of this is taken from 

* [[http://www.ntop.org/products/n2n/]]

* [[https://github.com/lukablurr/n2n_v2_fork/blob/master/doc/multiple-supernodes.pdf]]

* [[http://listgateway.unipi.it/mailman/listinfo/n2n]]

* [[http://listgateway.unipi.it/pipermail/n2n/2009-October/000300.html]]

h2. Install

<pre><code class="bash">

yum install n2n

</code></pre>

h2. manual testing

h3. starting Supernode

<pre><code class="bash">

supernode -l 5422

</code></pre>

h3. setting up firewall

in order to access the supernode from one of the edge-clients the given UDP-port must be accessible from outside. Therefore we need to open the firewall.

<pre><code class="bash">

system-config-firewall-tui

</code></pre>

h2. running n2n-Supernode as a service

if everything is working as expected we maybe want n2n-Supernode to survive a system-reboot.

The following should work without modification for RHEL/CentOS linux and similar:

Create a folder /etc/n2n and create configuration files (as described below) using following file name format:

<pre><code class="bash">

mkdir /etc/n2n

</code></pre>

<pre><code class="bash">

supernode-gw1.example.com

supernode-gw2.example.com

supernode-*.example.com

</code></pre>

The interesting contents of supernode-gw1.example.com would look similar to this:

<pre><code class="bash">

vim /etc/n2n/supernode-gw1.example.com

</code></pre>

<pre>

# == supernode config values parsed by /etc/rc.d/init.d/edged ==

# Read 'man supernode' for details about these values...

#

# Example port number to listen on...

N2N_PORT="8765"

# Verbose or not (-v logs to std out)...

#   N2N_OPTS="-v"

N2N_OPTIONS=""

# === end supernode-gw1.example.com config file ================

</pre>

Read comments in the scripts below to make more sense out of how they work.

Here are copies of some scripts that work when used with configuration files as described above:

<pre><code class="bash">

vim /etc/init.d/supernoded

</code></pre>

<pre>

#!/bin/sh

# $Id: supernoded.init,v 1.9 2009/10/23 12:34:56

# n2n supernode startup script.

#

# chkconfig:    345 96 26

# processname:  supernode

# pidfile:      /var/run/n2n-supernode.pid

#

# short-description: Provides client-to-client VPN access via Internet

# description: This is startup script for n2n 'edge',

#   n2n edge + supernode provide internet connection for vpn peers

#

# SEE:

#   for more options n2n 'man edge' and 'man supernode'

#

# NOTE:

#   Option to enter 'debug' as second var: e.g 'supernode start debug'

#   Using grep -w switch searches for whole word reduces ambiguity

#   Comment in/out the 'echo' stuff depending if thigs work as expected

#   Config files located/named in: /etc/n2n/supernode-your.example.com

#   Assumes CentOS linux init scripts located in /etc/rc.d/init.d/

#

# Created: FOOFORCE RB 2009-10-24

# License GPL: free to copy, improve and use.

# http://fuji.unipi.it/pipermail/n2n/2009-October/000300.html

# ===============================================================

# ==== main init script variables ===============================

# Make sure you include path where 'supernode' + sh + tools are installed..

# PATH="/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin"

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

# The name + path to the program/daemon...

NAME="supernode"

DAEMON="/usr/sbin/${NAME}"

# Modify $NAME to filter on 'grep -w [s]supernode' - faster than 'grep -v grep'...

GREPNAME=$(echo "[s]${NAME#s}")

# Enable some simple debug messages when running this script...

if [[ "${2}" == "debug" ]]; then

    echo "DEBUG: ${GREPNAME}"

fi

PIDFILE="/var/run/supernode.pid"

LOGFILE="/var/log/n2n-${NAME}.log"

STAMP=$(/bin/date +"%d/%b/%Y %H:%M:%S")

# Get the host/domain name to identify local configfile..

HOST=$(/bin/hostname)

FQDN=$(/bin/hostname -f)

# Initialise configfile variable to empty value...

CONFIGDIR="/etc/n2n"

# Initialise configfile variable to empty value...

CONFIGFILE=""

# Source function library.

. /etc/rc.d/init.d/functions

# Load values from configfile using our local domain name:

# Example:

#   Our local FQDN = 'myhost.example.com'

#   Our configfile = 'supernode-myhost.example.com'

#

# if [[ "${HOST}" == "" ]]; then

if [[ "${FQDN}" == "" ]]; then

    echo " ERROR: Missing ${FQDN} hostname in config file /etc/rc.d/init.d/${NAME}"

    exit 1

else

    CONFIGFILE="/etc/n2n/supernode-${FQDN}"

fi

if [[ -f "${CONFIGFILE}" ]]; then

    # Get values from local configuration file...

    if [[ "${2}" ==  "debug" ]]; then

        echo " Found config file: ${CONFIGFILE}"

    fi

    . ${CONFIGFILE}

else

    echo "ERROR: Missing config file ${CONFIGFILE}"

    exit 1

fi

# See if pid file exists and get pid number...

if [[ -f "${PIDFILE}" ]]; then

    CURPID=$(cat ${PIDFILE})

fi

# Quit if we can't find application...

test -f ${DAEMON} || exit 0

set -e

# Set any value to enable this script...

# N2N_RUN=1

#

# test -n "${N2N_RUN}" || exit 0

# Optionaly change into n2n config directory...

if [[ -d "${CONFIGDIR}" ]]; then

    cd ${CONFIGDIR}

fi

# ==============================================================

# Should not need to change much below here...

# ==== see how we were called  + act accordingly ===============

if [ "${N2N_PORT}" == "" ]; then

    N2N_PORT="1304"

    echo "No port specified in ${CONFIGFILE} - using  default port: ${N2N_PORT}"

fi

case "${1}" in

    start)

        # echo " ${NAME} ${1} process is ${0} on pid: ${$})..."

        echo "${STAMP} start n2n /etc/rc.d/init.d/${NAME}" >> ${LOGFILE}

        if [[ -n "${CURPID}" ]]; then

            echo " A PID:${CURPID} already exists for ${0}:"

            echo " To re-start with current config settings, run '$0 stop' then '$0 start' ..."

        else

        if [ -d /var/lock/subsys ] ; then

            touch /var/lock/subsys/${NAME};

        fi

            # ====================================================

            # All variables read from ${CONFIGFILE}...

            # If variable value not empty then add command-line switch to variable...

            if [[ -n "${N2N_PORT}" ]]; then

                N2N_PORT="-l ${N2N_PORT}";

            fi

            # next line for debug:

            if [[ "${2}" == "debug" ]]; then

                echo " DEBUG: ${DAEMON} ${N2N_PORT} ${N2N_OPTIONS}"

            fi

            # Execute the command + switches + values sources from config file...

            echo -n $"Starting $NAME: "

            ${DAEMON} ${N2N_PORT} ${N2N_OPTIONS} >> ${LOGFILE} &

            RETVAL=$?

            [ $RETVAL -eq 0 ] && echo_success

            [ $RETVAL -ne 0 ] && echo_failure

            echo

            # =================================================

            if [[ "${2}" ==  "debug" ]]; then

                echo " NOTICE: Creating new ${NAME} pidfile - deleting old ${CURPID}..."

            fi

            rm -f ${PIDFILE}

            touch ${PIDFILE}

            for PID in $(ps ax | grep -w "${GREPNAME}" | grep -v "(restart|stop|start)" | awk '{ print $1 }'); do

                if [[ "${2}" ==  "debug" ]]; then

                    echo " Saving into pidfile - new pid: ${PID}"

                fi

                echo ${PID} >> ${PIDFILE}

            done

        fi

        ;;

    stop)

        # echo " DEBUG: Searching for at least one live process id..."

        PID=$(ps ax | grep -w "${GREPNAME}" | grep -v "(restart|stop|start)" | awk '{ print $1 }')

        if [[ "${2}" == "debug" ]]; then

            echo " This ${NAME} ${1} init query ${0} is running on pid: ${$}) for ${PID}..."

        fi

        # echo " ${NAME} ${1} process is ${0} on pid: ${$})..."

        echo "${STAMP} stop /etc/rc.d/init.d/${NAME}" >> ${LOGFILE}

        # echo "  NOTICE: Kill name:${NAME} pid:${pid} before stopping..."

        # kill -9 $(cat /var/run/${NAME}_pid) && rm /var/run/${NAME}_pid

        # If a pid value found in file or in process id, then kill it...

        if [[ -n "${PID}" ]]; then

            echo -n  $"Stopping ${NAME}: "

            # kill -9 $(cat /var/run/${NAME}.pid) && rm /var/run/${NAME}.pid

            kill ${PID}

            RETVAL=$?

            sleep 4s

            rm -f ${PIDFILE}

            if [ $RETVAL -eq 0 ] ; then

                echo_success

                echo

            else

                echo_failure

                echo

            fi

        else

            # Else assume stale pid...

            if [[ "${2}" == "debug" ]]; then

                echo " NOTICE: No current active process ${PID}..."

            fi

            if [[ -f "${PIDFILE}" ]]; then

                rm -f "${PIDFILE}"

            fi

        fi

        # Indiscriminate pid killer...

        # for PID in $(ps ax | grep -w ${NAME} | grep -v stop | awk '{ print $1 }'); do

        #    echo " Killing currently active ${NAME} pid(s): ${PID}"

        #    # kill -HUP $PID

        #    kill ${PID}

        # done

        if [ -f /var/lock/subsys/${NAME} ]; then

            if [[ "${2}" ==  "debug" ]]; then

                echo " Removing stale lock..."

            fi

            rm -f /var/lock/subsys/${NAME}

        fi

        if [ -f "${PIDFILE}" ]; then

            echo " Removing stale pidfile..."

            rm -f ${PIDFILE}

        fi

        ;;

    restart)

        echo "* Re-start ${NAME}..."

        ${0} stop ${2}

        # Not a race...

        sleep 4s

        ${0} start ${2}

        ;;

    status)

        # status ${NAME}

        if [[ "${2}" == "debug" ]]; then

            echo " This init script ${NAME} ${1} query ${0} is running on pid: ${$})..."

        fi

        PID=$(ps ax | grep -w "${GREPNAME}" | grep -v status | awk '{ print $1 }')

        # If at least one active session then find all...

        if [[ -n "${PID}" ]]; then

            for PID in $(ps ax | grep -w "${GREPNAME}" | grep -v status | awk '{ print $1 }'); do

                if [[ -n "${PID}" ]]; then

                    echo "${NAME} (pid ${PID}) is running..."

                else

                    echo "${NAME} is stopped"

                fi

            done

        else

            echo "${NAME} is stopped"

        fi

        ;;

    *)

        echo " Usage: ${0} {start|stop|status|restart|any debug}" >&2

        exit 1

        ;;

esac

exit 0

# === end supernoded ======================================

</pre>

make init-script executeable

<pre><code class="bash">

chmod +x /etc/init.d/supernoded

</code></pre>

Using CentOS tools to activate the systemV init scripts:

<pre><code class="bash">

chkconfig --add supernoded

chkconfig supernoded on

</code></pre>

Command line syntax:

<pre><code class="bash">

service supernoded [start|stop|restart|any debug]

</code></pre>

For example:

<pre><code class="bash">

service supernoded restart

</code></pre>

… OR…

<pre><code class="bash">

service supernoded restart debug

</code></pre>

provides some extra clues.