Virtual Ip With Keepalived as Front end for HAproxy server's

Install Keepalived
Virtual Ip 192.168.216.100

HAproxy Ip 192.168.216.101
1. Install Keepalived package:

On RHEL/CentOS:

$ yum install -y centos-release
$ yum install -y keepalived
$ chkconfig keepalived on

2. Tell kernel to allow binding non-local IP into the hosts and apply the changes:

$ echo "net.ipv4.ip_nonlocal_bind = 1" >> /etc/sysctl.conf
$ sysctl -p

Configure Keepalived and Virtual IP
1. Login into LB1 and add following line into /etc/keepalived/keepalived.conf:

vrrp_script chk_haproxy {
script "killall -0 haproxy" # verify the pid existance
interval 2 # check every 2 seconds
weight 2 # add 2 points of prio if OK
}

vrrp_instance VI_1 {
interface eth2 # interface to monitor
state MASTER
virtual_router_id 51 # Assign one ID for this route
priority 101 # 101 on master, 100 on backup
virtual_ipaddress {
192.168.216.100 # the virtual IP
}
track_script {
chk_haproxy
}
}
2. Login into LB2 and add following line into /etc/keepalived/keepalived.conf:

vrrp_script chk_haproxy {
script "killall -0 haproxy" # verify the pid existance
interval 2 # check every 2 seconds
weight 2 # add 2 points of prio if OK
}

vrrp_instance VI_1 {
interface eth2 # interface to monitor
state MASTER
virtual_router_id 51 # Assign one ID for this route
priority 100 # 101 on master, 100 on backup
virtual_ipaddress {
192.168.216.100 # the virtual IP
}
track_script {
chk_haproxy
}
}
3. Start Keepalived in both nodes:

$ sudo /etc/init.d/keepalived start
4. Verify the Keepalived status. LB1 should hold the VIP and the MASTER state while LB2 should run as BACKUP state without VIP:

LB1 IP:

$ ip a | grep -e inet.*eth2
inet 192.168.216.101/24 brd 192.168.216.255 scope global eth2
inet 192.168.216.100/32 scope global eth2

Mysql HA with Haproxy and Master-Master replication

Once Mysql master -master replication is done we set HA with those using HAproxy

http://enekumvenamorublog.wordpress.com/2014/06/25/mysql-replication-master-master/

HAProxy

yum install haproxy

To use Haproxy with MYsql we need to create a user in mysql so that haproxy can access it .

GRANT ALL PRIVILEGES ON *.* TO 'haproxy'@'192.168.216.180' IDENTIFIED BY '';

Sample configuration  /etc/haproxy/haproxy.cfg

global
log 127.0.0.1 local0 notice
user haproxy
group haproxy

# turn on stats unix socket
stats socket /var/lib/haproxy/stats mode 777

defaults
log global
retries 2
timeout connect 1000
timeout server 5000
timeout client 5000
listen stats 192.168.255.180:80
mode http
stats enable
stats uri /stats
stats realm HAProxy\ Statistics
stats auth admin:password

listen MYSQL 192.168.255.190:3306
balance source
mode tcp
option mysql-check user haproxy
server controller1 192.168.216.130 check
server controller2 192.168.216.135 check
[root@HAPROXY ~]#

Enable HAProxy logging on Centos

Enable HAProxy logging on CentOS
By default, HAProxy will not log to files unless we make some modifications
1. Create rsyslog configuration file
nano /etc/rsyslog.d/haproxy.conf
Add these lines to the file
# Enable UDP port 514 to listen to incoming log messages from haproxy
$ModLoad imudp
$UDPServerRun 514
$template Haproxy,"%msg%\n"
local0.=info -/var/log/haproxy/haproxy.log;Haproxy
local0.notice -/var/log/haproxy/admin.log;Haproxy
# don't log anywhere else
local0.* ~
Restart rsyslog service
/etc/init.d/rsyslog restart
Ref: http://blog.hintcafe.com/post/33689067443/haproxy-logging-with-rsyslog-on-linux
2. Modify the log rotate config to match the new folder:
nano /etc/logrotate.d/haproxy
Change
/var/log/haproxy.log {
daily
rotate 10
missingok
[...]
to
/var/log/haproxy/*.log {
daily
rotate 10
missingok
[...]
Now we can check if HAProxy logging is working.
tail -f /var/log/haproxy/haproxy.log

===================================================

global to have these messages end up in /var/log/haproxy.log you will need to:

1) configure syslog to accept network log events. This is done by adding the '-r' option to the SYSLOGD_OPTIONS in /etc/sysconfig/syslog

2) configure local2 events to go to the /var/log/haproxy.log file. A line like the following can be added to /etc/sysconfig/syslog
local2.* /var/log/haproxy.log

In haproxy conf file add
log 127.0.0.1 local2 info