ubuntu@haproxy-node01:~$ sudo apt-get install haproxy -y

ubuntu@haproxy-node01:~$ sudo sed -i s/0/1/ /etc/default/haproxy

ubuntu@haproxy-node01:~$ sudo service haproxy start

ubuntu@haproxy-node01:~$ sudo netstat -plantu | grep 3306
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      3729/haproxy

ubuntu@haproxy-node01:~$ mysql -uroot -proot -h127.0.0.1 -e "show variables like 'wsrep_node_name' ;"
+-----------------+---------------+
| Variable_name   | VALUE         |
+-----------------+---------------+
| wsrep_node_name | galera-node01 |
+-----------------+---------------+
ubuntu@haproxy-node01:~$ mysql -uroot -proot -h127.0.0.1 -e "show variables like 'wsrep_node_name' ;"
+-----------------+---------------+
| Variable_name   | VALUE         |
+-----------------+---------------+
| wsrep_node_name | galera-node02 |
+-----------------+---------------+
ubuntu@haproxy-node01:~$ mysql -uroot -proot -h127.0.0.1 -e "show variables like 'wsrep_node_name' ;"
+-----------------+---------------+
| Variable_name   | VALUE         |
+-----------------+---------------+
| wsrep_node_name | galera-node03 |
+-----------------+---------------+

$ sudo apt-get install xinetd -y
$ wget -O /usr/bin/clustercheck https://raw.githubusercontent.com/olafz/percona-clustercheck/master/clustercheck
$ sudo chmod 755 /usr/bin/clustercheck

$ sudo cat > /etc/xinetd.d/mysqlchk <<EOF
# default: on
# description: mysqlchk
service mysqlchk
{
        disable = no
        flags = REUSE
        socket_type = stream
        port = 9200
        wait = no
        user = nobody
        server = /usr/bin/clustercheck
        log_on_failure += USERID
        only_from = 0.0.0.0/0
        bind = <galera_public_interface>
        per_source = UNLIMITED
}
EOF

$ sudo echo "mysqlchk   9200/tcp" | tee -a /etc/services

$ sudo service xinetd restart

#!/bin/bash
#A hot reconfiguration script would look like this :
#Extract from http://haproxy.1wt.eu/download/1.3/doc/architecture.txt

# save previous state
mv /etc/haproxy/config /etc/haproxy/config.old
mv /var/run/haproxy.pid /var/run/haproxy.pid.old

mv /etc/haproxy/config.new /etc/haproxy/config
kill -TTOU $(cat /var/run/haproxy.pid.old)
if haproxy -p /var/run/haproxy.pid -f /etc/haproxy/config; then
    echo "New instance successfully loaded, stopping previous one."
    kill -USR1 $(cat /var/run/haproxy.pid.old)
    rm -f /var/run/haproxy.pid.old
    exit 1
else
    echo "New instance failed to start, resuming previous one."
    kill -TTIN $(cat /var/run/haproxy.pid.old)
    rm -f /var/run/haproxy.pid
    mv /var/run/haproxy.pid.old /var/run/haproxy.pid
    mv /etc/haproxy/config /etc/haproxy/config.new
    mv /etc/haproxy/config.old /etc/haproxy/config
    exit 0
fi

#!/bin/sh
#
# glbd          Start/Stop the Galera Load Balancer daemon.
#
# processname: glbd
# chkconfig: 2345 90 60
# description: GLB is a TCP load balancer similar to Pen. \
#              It lacks most of advanced Pen features, as \
#              the aim was to make a user-space TCP proxy which is \
#              as fast as possible. It can utilize multiple CPU cores. \
#              A list of destinations can be configured at runtime. \
#              Destination "draining" is supported. It features \
#              weight-based connection balancing (which becomes \
#              round-robin if weights are equal).

### BEGIN INIT INFO
# Provides: glbd
# Required-Start: $local_fs
# Required-Stop: $local_fs
# Default-Start:  2345
# Default-Stop: 90
# Short-Description: run glbd daemon
# Description: GLB is a TCP load balancer similar to Pen.
### END INIT INFO

prog="glbd"
proc=glbd
exec=/usr/sbin/glbd

LISTEN_PORT="8010"
CONTROL_PORT="8011"
THREADS="2"
DEFAULT_TARGETS="djdb2:8000:0.75 djdb3:8000:0.75 divjobs3:8000:0.75 divjobs4:8000:1"

stop() {
	echo -n "[`date`] $prog: stopping... "
	killall $exec &> /dev/null
	if [ $? -ne 0 ]; then
		echo "failed."
		return
	fi
	echo "done."
}

start() {
	if pidof $prog &> /dev/null ; then
		echo "[`date`] $prog: already running...";
		exit -1
	fi
	echo "[`date`] $prog: starting..."
	wait_for_connections_to_drop
	$exec --daemon --control 127.0.0.1:$CONTROL_PORT --threads $THREADS $LISTEN_PORT $DEFAULT_TARGETS
	PID=$!
	if [ $? -ne 0 ]; then
		echo "[`date`] $prog: failed to start."
		exit -1
	fi
	echo "[`date`] $prog: started, pid=$PID"
	exit 0
}

restart() {
	echo "[`date`] $prog: restarting..."
	stop
	start
}

wait_for_connections_to_drop() {
	while (netstat -na | grep -m 1 ":$LISTEN_PORT" &> /dev/null); do
		echo "[`date`] $prog: waiting for lingering sockets to clear up..."
		sleep 1s
	done;
}

getinfo() {
	echo getinfo | nc 127.0.0.1 $CONTROL_PORT && exit 0
	echo "[`date`] $prog: failed to query 'getinfo' from 127.0.0.1:$CONTROL_PORT"
	exit -1
}

getstats() {
	echo getstats | nc 127.0.0.1 $CONTROL_PORT && exit 0
	echo "[`date`] $prog: failed to query 'getstats' from 127.0.0.1:$CONTROL_PORT"
	exit -1
}

add() {
	if [ "$1" == "" ]; then
		echo $"Usage: $0 add <ip>:<port>[:<weight>]"
		exit -1
	fi
	if [ "`echo "$1" | nc 127.0.0.1 $CONTROL_PORT`" == "Ok" ]; then
		echo "[`date`] $prog: added '$1' successfully"
		#getinfo
		exit 0
	fi
	echo "[`date`] $prog: failed to add target '$1'."
	exit -1
}

remove() {
	if [ "$1" == "" ]; then
		echo $"Usage: $0 remove <ip>:<port>"
		exit -1
	fi
	if [ "`echo "$1:-1" | nc 127.0.0.1 $CONTROL_PORT`" == "Ok" ]; then
		echo "[`date`] $prog: removed '$1' successfully"
		#getinfo
		exit 0
	fi
	echo "[`date`] $prog: failed to remove target '$1'."
	exit -1
}

case $1 in
	start)
		start
	;;
	stop)
		stop
	;;
	restart)
		restart
	;;
	getinfo)
		getinfo
	;;
	getstats)
		getstats
	;;
	status)
		getinfo
	;;
	add)
		add $2
	;;
	remove)
		remove $2
	;;
	*)
		echo $"Usage: $0 {start|stop|restart|status|getstats|getinfo|add|remove}"
	exit 2
esac