How to do installation and configuration of haproxy and load balancer using Ansible ?

What is Ansible ?

Ansible automates and simplifies repetitive, complex, and tedious operations. Everybody likes it because it brings huge time savings when we install packages or configure large numbers of servers. Its architecture is simple and effective. It works by connecting to your nodes and pushing small programs to them. These programs make the system comply with a desired state, and, when they have finished their tasks, they are deleted.

What is Haproxy ?

HAProxy is an open source, free, very fast and reliable solution offering high availability, load balancing and proxying for TCP and HTTP-based applications.  It is particularly suited for web sites crawling under very high loads while needing persistence or Layer7 processing. It distributes a workload across a set of servers to maximize performance and optimize resource usage. HAProxy can be used for Web applications (HTTP/ HTTPS) as well as for TCP based applications (MySQL, SSL, SMTP) etc.

What is Load Balancer ?

A load balancer is a device that acts as a reverse proxy and distributes network or application traffic across a number of servers. Load balancers are used to increase capacity (concurrent users) and reliability of applications.

Prerequisites for HAProxy and Load Balncer:-

• Ansible must be installed on controller node
• HAProxy is required to be install on one of Managed Nodes
• Apache Web Server (HTTPD) must be configure on Target Nodes.

Steps to Configure Load Balancer :-

• First of all configure ansible configuration file at location " /etc/ansible/ansible.cfg " .

• Second Step is to configure the Inventory of ansible on controller node by writing IP, User_name, Password of each Managed or Target Node.

• Third Step is to make php file so that it can be cpoied on managed node for future use :-

<pre>
<?php
print `/usr/sbin/ifconfig`;
?>
</pre>

• Fourth Step is to configure or modify " /etc/haproxy/haproxy.cfg " file using jinja template:-

#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   https://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 local2


    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
#---------------------------------------------------------------------
frontend  main
    bind *:8080
    acl url_static       path_beg       -i /static /images /javascript /stylesheets
    acl url_static       path_end       -i .jpg .gif .png .css .js


    use_backend static          if url_static
    default_backend             app


#---------------------------------------------------------------------
# static backend for serving up images, stylesheets and such
#---------------------------------------------------------------------
backend static
    balance     roundrobin
    server      static 127.0.0.1:4331 check


#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend app
    balance     roundrobin
    {% for ip in groups['Web_Server'] %}
    server  app{{ loop.index }} {{ ip }}:80 check
    {% endfor %}

• The Last Step of ansible-playbook on controller node for downloading, installing and configuring httpd and HAProxy on target node (instances) to make load balancer and web-server :-

- hosts: Web_Server
  tasks:
  - name: "Installling Apache "
    package:
            name: httpd,php
            state: present


  - name: "Copying Web Pages"
    template: 
            src: "/Arth-task-12/index.php"
            dest: "/var/www/html/index.php"
    register: web
  
  - name: "Strating Web Server"
    service:
            name: httpd
            state: started


  - name: "Restarting Web Serer After Configuration"
    service:
            name: httpd
            state: restarted
    when: web.changed == True


- hosts: Load_Balancer
  tasks:
  - name: "Installing and Configuring Load Balancer"
    package:
            name: haproxy
            state: present
   
  - name: "Configuring HAPROXY"
    template:
            src: /Arth-task-12/haproxy.cfg
            dest: /etc/haproxy/haproxy.cfg
    register: x 


  - name: "Starting Haproxy"
    service:
            name: haproxy
            state: started


  - name: "Started Haproxy with new configuration"
    service:
            name: haproxy
            state: restarted
    when: x.changed == True

Note:- In this ansible-playbook, I had written two playbook one for load balancer and other for web server.

Now let's run the PlayBook -

Note:- Load Balancer works on Port 8080

Lets Check the OutPut -

Here you can see my Load balancer is working. I'm getting ip of my backend server that means this webpage is running on my backend server.

Thank You for reading....

GitHub Link -

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