LOAD BALANCER USING ANSIBLE

In this blog, We are going to launch HAPROXY LoadBalancer and multiple WebServers on the top of the RHEL8 Linux through Ansible.

What is Load Balancer?

Load balancing refers to the process of distributing a set of tasks over a set of resources, with the aim of making their overall processing more efficient.

HAProxy (High Availability Proxy) is a TCP/HTTP load balancer and proxy server that allows a webserver to spread incoming requests across multiple endpoints.

Ansible

Ansible is a software tool that provides simple but powerful automation for cross-platform computer support. It is primarily intended for IT professionals, who use it for application deployment, updates on workstations and servers, cloud provisioning, configuration management, intra-service orchestration, and nearly anything a systems administrator does on a weekly or daily basis. Ansible doesn’t depend on agent software and has no additional security infrastructure, so it’s easy to deploy.

Let’s dev into a practical

Here we are taking three OS’s, one OS for LoadBalancer and twoOS for Managed nodes

Load Balancer

Server One

Server Two

Prerequisite:

Ansible should be Installed in the system

Linux basics

Step 1: Now we are going to add IP’s which need to configured in the static inventory file by the name of Inventory1

>> vim Inventory1

Here I used vim editor you can use any like vi, gedit, etc

[WebServer]
192.168.43.208 ansible_user=root ansible_ssh_pass=password ansible_connection=ssh
192.168.43.163 ansible_user=root ansible_ssh_pass=password ansible_connection=ssh
[Controller]
192.168.43.202 ansible_user=root ansible_ssh_pass=password ansible_connection=ssh

Add this code inside the Inventory1 file

Step 2: Configure ansible.cfg file and below code

Note: don’t use the inventory file name to any file

[defaults]
inventory= Inventory1
host_key_checking=false
[privilege-escalation]
become=true
become_method=sudo
become_user=root
become_ask_pass=false

Step 3: Copy HAproxy from /etc/haproxy/haproxy.cfg file to this directory then edit as below to get Dynamic IP from Inventory file

>> yum install haproxy -y
>> cp /etc/haproxy/haproxy.cfg /ReverseProxy/haproxy.cfg

After copying edit that file

Go to last and edit backend app at

backend app
    balance     roundrobin
    {% for i in groups['WebServer'] %}
    server  app{{ loop.index }} {{ i }}:8080 check
    {% endfor %}
       #server  app2 192.168.43.254:80 check
     #server  app3 192.168.43.89:6085 check
   # server  app4 127.0.0.1:5004 check

In the below code replace with backend app session even this frontend main
bind *:80

global
    log         127.0.0.1 local2
chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    stats socket /var/lib/haproxy/stats
    ssl-default-bind-ciphers PROFILE=SYSTEM
    ssl-default-server-ciphers PROFILE=SYSTEM

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

frontend main
    bind *:80
    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

backend static
    balance     roundrobin
    server      static 127.0.0.1:4331 check
backend app
    balance     roundrobin
    {% for i in groups['WebServer'] %}
    server  app{{ loop.index }} {{ i }}:8080 check
    {% endfor %}

Step 4: Now create an ansible playbook to setup Load Balancer using HAPROXY

Add this code in ReverseProxy.yml file

- hosts: Controller
  tasks:
  - name: "Haproxy install or check"
    package: 
      name: haproxy
      state: present
- name: "Start HAPROXY Service"
    service: 
      name: haproxy
      state: started
- name: "Configure haproxy.cfg file"
    template:
      src: haproxy.cfg
      dest: "/etc/haproxy/haproxy.cfg"
    notify:
      - Restart service
handlers:    
    - name: "Restart service"
      service: 
        name: haproxy
        state: restarted
- hosts: WebServer
  tasks:
  - name: "Haproxy install or check"
    package:
      name: httpd
      state: present
#- name: "ifconfig IP"i
  - name: "Copy Content to a file index.html"
    copy:
      content: "<pre>
      <h1 style='color:green;font-size:100px;text-align:center'>This is LoadBalancer</h1> 
      <h1 style='color:skyblue;text-align:center;font-size:40px;'>This is Server IP {{ hostvars[inventory_hostname]['ansible_env'].SSH_CONNECTION.split(' ')[2] }} </h1>
      </pre>"
      dest: "/var/www/html/index.html"
    notify: 
      - Restart httpd Service
  - name: "Start a httpd Server"
    service: 
      name: httpd
      state: started  
  
  handlers:    
    - name: "Restart httpd Service"
      service: 
        name: httpd
        state: restarted

Files needed

Successfully configured both Load Balancer and Servers

Here we can see Server is configured and automatically fetched IP and PORT number from a inventory file

>> ansible-playbook <playbookName>

Now we can check whether our load balancer is working or not. Take public IP of load balancer with port 80 (binding port) as we see in the video

Step 5: Adding one more SERVER only thing needed to do is just configure inventory everything will be automated

Now run playbook to configure

Now we can check whether our load balancer is working or not. Take public IP of load balancer with port 80 (binding port) as we see in the video

The below image shows us by clicking on load balancer IP and port(192.168.43.208:80) it's connecting us to different servers i.e., Server1: 192.168.43.202:80 and Server2: 192.168.43.220:80 and reducing traffic

GitHub code:

Vinodhakumara/LoadBalancer

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