====== haproxy ======
===== Install =====
  * Download haproxy and change directory to download directory
  * Run make and make install as root
==== Make ====
To choose TARGET run
<code bash>
uname -a
</code>
Output:
<code>
Linux somehost 2.6.32-358.11.1.el6.x86_64 #1 SMP Wed May 15 10:48:38 EDT 2013 x86_64 x86_64 x86_64 GNU/Linux
</code>
Considering the above was kernel 2.6, using TARGET as below.

<code bash>
make TARGET=linux2628 USE_PCRE=1 USE_LIBCRYPT=1 USE_LINUX_SPLICE=1 USE_LINUX_TPROXY=1
</code>
Some options listed may not work - feel free to remove them such as ''USE_PCRE=1''

==== Make Install ====
<code bash>
make install
</code>
haproxy typically gets installed at ''/usr/local/sbin/haproxy''

===== Configuration =====
To configure, create a configuration file at chosen location.  Preferred: /etc/haproxy/haproxy.cfg
  * Load balance on port 8000
  * Sticky sessions between multiple servers (someserver1 & someserver2)
  * Add administration (port 7999) 

<code>
global
    daemon
    maxconn 4096

defaults
    mode http
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms

frontend http-in
    bind *:8000
    default_backend servers

backend servers
    retries 2
    fullconn 4096
    balance roundrobin
    cookie SERVERID insert indirect nocache
    server server01 someserver1:8080 check cookie s01
    server server02 someserver1:8081 check cookie s02
    server server03 someserver1:8082 check cookie s03
    server server04 someserver2:8090 check cookie s04
    server server05 someserver2:8091 check cookie s05
    server server06 someserver2:8092 check cookie s06

listen stats :7999
    mode http
    stats enable
    stats hide-version
    stats realm Haproxy\ Statistics
    stats uri /
</code>

===== Start =====
Simple way to start is as below.  This runs as a daemon, since daemon is specified in the configuration.  If not, add option -D.
<code bash>
haproxy -f /etc/haproxy/haproxy.cfg
</code>

===== Logging =====
==== Update /etc/rsyslog.conf and related ====
Edit /etc/rsyslog.conf and uncomment:
<code>
$ModLoad imudp
$UDPServerRun 514
</code>

Edit /etc/rsyslog.d/haproxy.conf and append line:
<code>
local2.* /var/log/haproxy.log
</code>

Restart rsyslog:
<code>
service rsyslog restart
</code>

Change permissions on log file:
<code>
chmod o+r /var/log/haproxy.log
chmod g+r /var/log/haproxy.log
</code>

==== Update /etc/haproxy/haproxy.cfg ====
Edit /etc/haproxy/haproxy.cfg:\\

Add line in ''global section'':
<code>
    log 127.0.0.1 local2
</code>

Add lines to ''frontend http-in'' section:
<code>
    option httplog
    log global
</code>

Restart haproxy


==== Logging Resources ====
  * https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/3/html/Installation_and_Configuration_Guide/Configuring_the_rsyslog_Server.html
  * https://transloadit.com/blog/2010/08/haproxy-logging/
  * http://www.percona.com/blog/2014/10/03/haproxy-give-me-some-logs-on-centos-6-5/
  * http://cbonte.github.io/haproxy-dconv/configuration-1.5.html#8