A.3. Install and Configure keepalived

# yum install -y keepalived

# vim /etc/keepalived/keepalived.conf

vrrp_script chk_haproxy {
  script "killall -0 haproxy" # check the haproxy process
  interval 2 # every 2 seconds
  weight 2 # add 2 points if OK
}

vrrp_instance VI_1 {
  interface eth0 # interface to monitor
  state MASTER # MASTER on haproxy, BACKUP on haproxy2
  virtual_router_id 51
  priority 101 # 101 on haproxy, 100 on haproxy2
  virtual_ipaddress {
    192.168.0.100 # virtual ip address
  }
  track_script {
    chk_haproxy
  }
}

# systemctl enable keepalived
# systemctl start keepalived