Haproxy is the hardware load balancer that most commonly
used by the industry. Also it is a later 7 load balancer which means you can
load balance many (any) backend via haproxy load balancer.
But there will be a problem when you many backend using
single load balancer node. Because there is a possibility of fail the load
balancer. Then whole system will stop and you have wait until the server up and
run or you have to setup new load balancer immediately. Because of that you
have to have a mechanism to overcome this problem.
We can setup keeplived to face ip failover which is ship
separately with haproxy. To setup keepalived we have to have two haproxy load
balancer servers. And we need virtual ip (VIP) to front load balancers.
In this post I’m going to show how to load balance two eap
servers via failover haproxy load balancers through keepalived.
Lb1,
Eth0 – xxx.xxx.xxx.12
Eth1 – xxx.xxx.xxx.17 (VIP)
Lb2,
Eth0 – xxx.xxx.xxx.13
Eth1 – xxx.xxx.xxx.17 (VIP)
Eap1 & eap2,
xxx.xxx.xxx.14
Before starting configurations on haproxy and keepalived
there are some common things to consider.
First one is selinux in linux machine. Since haproxy is
hardware load balancer we have to insert selinux rules before start working.
Check this post I previously posted how to add selinux policies to enable
ports.
But in this time I’m going to disable selinux in my haproxy
machines. Do below exercise to disable selinux.
[root@localhost
~]# vi /etc/sysconfig/selinux
Now reboot the machine to apply changes
[root@localhost
~]# reboot
Second consideration is firewall setting of the machine. I
am going to disable firewall to make easy configurations,
Now install haproxy and keepalived in two load balancer
machines,
[root@localhost ~]# yum install keepalived
[root@localhost
~]# yum install haproxy
Now install two EAPs in different servers.
Install jboss eap using jar installer (read how to installjboss eap using installer). Click to view how to install jboss eap
Start both eap instances. (Remember to change interface ipswith server ip. Because without doing that you cannot access eap instances fromany other machine)
Now you have to setup vip in load balancer servers.
Setting up vip in haproxy cluster
To do this you have to have separate two Ethernet
connections in both load balancer servers.
First one is for the machine ip and second one is for
virtual ip.
[root@localhost
~]# nmtui
After done configurations in virtual ip settings, now setup
haproxy configuration files in both load balancers,
Edit and insert below configurations to the haproxy conf
file,
[root@localhost
~]# vi /etc/haproxy/haproxy.cfg
And insert below code,
#---------------------------------------------------------------------
# Example configuration for a
possible web application. See the
# full configuration options
online.
#
#
http://haproxy.1wt.eu/download/1.4/doc/configuration.txt
#
#---------------------------------------------------------------------
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
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
#
log
127.0.0.1 local0
chroot
/var/lib/haproxy
pidfile
/var/run/haproxy.pid
maxconn
4000
user
haproxy
group
haproxy
daemon
# turn on stats unix socket
stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all
the 'listen' and 'backend' sections will
# use if not designated in
their block
#---------------------------------------------------------------------
defaults
mode http
log global
option httplog
option dontlognull
option http-server-close
option forwardfor except 127.0.0.0/8
option redispatch
retries 3
timeout http-request 10s
timeout queue 1m
timeout connect 10s
timeout client 1m
timeout server 1m
timeout http-keep-alive 10s
timeout check 10s
maxconn 3000
#---------------------------------------------------------------------
# main frontend which proxys
to the backends
#---------------------------------------------------------------------
listen webfarm *:80
mode http
stats enable
stats uri /haproxy?stats
stats realm Haproxy\ Statistics
stats auth haproxy:stats
# balance roundrobin
balance source
cookie LBN insert indirect nocache
option httpclose
option forwardfor
server eap1 xxx.xxx.xxx.14:8080 cookie
node1 check
server eap2 xxx.xxx.xxx.14:8081 cookie
node1 check
Start haproxy after done configurations,
[root@localhost
~]# systemctl start haproxy.service
Also you can log in
to the haproxy management panel using below url in browser
Then it will prompt to add username and password,
Give haproxy as username and stats as the password and click
ok.
Now change keepalived configuration file in both servers,
In lb1,
#
#
/etc/keepalived/keepalived.conf
#
global_defs {
notification_email {
mymails@mycompany.com
root@localhost
}
notification_email_from lb1@haproxycluster
router_id HAPROXY
}
vrrp_script
chk_haproxy {
script
"killall -0 haproxy"
interval 2
weight
2
}
vrrp_instance LB_VIP {
state MASTER
interface eno16780032 #this can be eth0
virtual_router_id 42
# Higher priority on other node
priority 101
advert_int
1
# notify
"/usr/local/bin/VRRP-notification.sh"
virtual_ipaddress {
xxx.xxx.xxx.17/24 dev eno33559296 #this
can be eth1
}
track_script {
chk_haproxy
}
authentication {
auth_type PASS
auth_pass 1111
}
}
In lb2,
#
#
/etc/keepalived/keepalived.conf
#
global_defs {
notification_email {
mymails@mycompany.com
root@localhost
}
notification_email_from lb2@haproxycluster
router_id HAPROXY
}
vrrp_script
chk_haproxy {
script
"killall -0 haproxy"
interval 2
weight
2
}
vrrp_instance LB_VIP {
# state BACKUP
state MASTER
interface eno16780032 #this can be eth0
virtual_router_id 42
# Higher priority on other node
priority 100
advert_int 1
# notify
"/usr/local/bin/VRRP-notification.sh"
virtual_ipaddress {
xxx.xxx.xxx.17/24 dev ens224 #this can
be eth1
}
track_script {
chk_haproxy
}
authentication {
auth_type PASS
auth_pass 1111
}
}
****Note that if you are using virtual machines, remember to
add Ethernet DEVICE NO instead of using Ethernet name.
Now you have successfully configured the haproxy load
balancer with keeplived ip failover mechanism.
To test the setup, simply invoke below url using any
accessible server and you can see EAP servers are working fine, 172.16.109.17
is the vip
You can achieve the same using DNS (domain name server)
configurations other than using virtual IP (VIP). To do that you have add a single
DNS entry for both two load balancers.
