HAProxy : Load Balancing on Layer42015/02/18

Configure HAProxy on Layer4 Mode.
This example based on the environment like follows.

       |
-------+-----------------------------------------------
       |
       +-------------------+--------------------+
       |10.0.0.30          |10.0.0.31           |10.0.0.32
 +-----+-----+     +-------+------+     +-------+------+
 | Frontend  |     |   Backend#1  |     |   Backend#2  |
 |  HAProxy  |     |    MariaDB   |     |    MariaDB   |
 +-----------+     +--------------+     +--------------+

[1]	Configure HAProxy.

[root@dlp ~]#

vi /etc/haproxy/haproxy.cfg

global
    log         127.0.0.1 local2 info
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     256
    maxsslconn  256
    user        haproxy
    group       haproxy
    daemon

defaults

# set "mode tcp" for Layer4

    mode               tcp
    log                global
    timeout connect    10s
    timeout client     30s
    timeout server     30s

# define frontend and backend servers

frontend  mysql-in
    bind *:3306
    default_backend    backend_servers

backend backend_servers
    balance            roundrobin
    server             db01 10.0.0.31:3306 check
    server             db02 10.0.0.32:3306 check

[root@dlp ~]#

systemctl restart haproxy

[2]	Make sure all works fine to access to the frontend server from a Client with SQL like follows.

[root@desktop ~]#

mysql -u keystone -p -h 10.0.0.30 keystone -e "select * from table01;"

Enter password:

+------+-------------------+
| id   | name              |
+------+-------------------+
|    1 | db01.srv.world |
+------+-------------------+

[root@desktop ~]#

mysql -u keystone -p -h 10.0.0.30 keystone -e "select * from table01;"

Enter password:

+------+-------------------+
| id   | name              |
+------+-------------------+
|    1 | db02.srv.world |
+------+-------------------+

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