How to configure HAProxy and automatic updation of it’s configuration file each time managed node is added using Ansible

Content

• About Ansible
• About HAProxy
• About Apache Httpd Webserver
• Project Understanding

About Ansible

What is Ansible ?

Ansible is a radically simple IT automation engine that automates cloud provisioning, configuration management, application deployment, intra-service orchestration, and many other IT needs.

Why use Ansible ?

1. Simple
   • Human readable automation
   • No special coding skills needed
   • Tasks executed in order
   • Get productive quickly


2. Powerful
   • App deployment
   • Configuration management
   • Workflow orchestration
   • Orchestrate the app lifecycle


3. Agentless
   • Agentless architecture
   • Uses OpenSSH and WinRM
   • No agents to exploit or update
   • Predictable, reliable and secure

For Ansible Documentation, visit the link mentioned below:
https://docs.ansible.com/

. . .

About HAProxy

• HAProxy is free, open source software that provides a high availability load balancer and proxy server for TCP and HTTP-based applications that spreads requests across multiple servers.
• It’s written in C and has a reputation for being fast and efficient in terms of processor and memory usage.

For HAProxy Documentation, visit the link mentioned below:
https://www.haproxy.com/documentation/hapee/latest/onepage/intro/

. . .

About Apache HTTPD Webserver

• The Apache HTTP Server, colloquially called Apache, is a free and open-source cross-platform web server software, released under the terms of Apache License 2.0.
• Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.
• The vast majority of Apache HTTP Server instances run on a Linux distribution, but current versions also run on Microsoft Windows, OpenVMS and a wide variety of Unix-like systems.

For Apache HTTPD Documentation, visit the link mentioned below:
https://httpd.apache.org/docs/

. . .

Project Understanding

Let's understand this implementation part by part

Part 1 : Ansible Playbook (main.yml)

Let's understand it task by task:

Common Tasks

• "Creation of directory to be mounted" : Creation of Mount Directory



- name: Creation of directory to be mounted
  file:
    state: directory
    path: "{{ mount_directory }}"



• "Mounting directory created to CDROM" : Mount the directory created in previous task to the CDROM



- name: Mounting directory created to CDROM
  mount:
    src: "/dev/cdrom"
    path: "{{ mount_directory }}"
    state: mounted
    fstype: "iso9660"



• "YUM Repository - AppStream" : Addition of AppStream YUM repository



- name: YUM Repository - AppStream
  yum_repository:
    baseurl: "{{ mount_directory }}/AppStream"
    name: "DVD1"
    description: "YUM Repository - AppStream"
    enabled: true
    gpgcheck: no



• "YUM Repository - BaseOS" : Addition of BaseOS YUM repository



- name: YUM Repository - BaseOS
  yum_repository:
    baseurl: "{{ mount_directory }}/BaseOS"
    name: "DVD2"
    description: "YUM Repository - BaseOS"
    enabled: true
    gpgcheck: no



• "Stopping Firewall Service" : Stops Firewall Service



- name: Stopping Firewall Service
  service:
    name: "firewalld"
    state: stopped
    enabled: yes



• "Setting SELinux Permissive" : Sets SELinux state to permissive



- name: Setting SELinux Permissive
  selinux:
    policy: targeted
    state: permissive

loadbalancer (HAProxy)

• "Installation of HAProxy Software" : Installs HAProxy Software



- name: Installation of HAProxy Software
  package:
    name: "haproxy"
    state: present



• "HAProxy Configuration File Setup" : Copies the configuration file from templates directory in the Controller Node to the default path of HAProxy configuration file in the Managed Node



- name: HAProxy Configuration File Setup
  template:
    dest: "/etc/haproxy/haproxy.cfg"
    src: "templates/haproxy.cfg"
  notify: Restart Load Balancer



• "Starting Load Balancer Service" : Starts HAProxy Service



- name: Starting Load Balancer Service
  service:
    name: "haproxy"
    state: started
    enabled: yes



• handlers - "Restart Load Balancer" : Starts HAProxy Service



- name: Restart Load Balancer
  systemd:
    name: "haproxy"
    state: restarted
    enabled: yes

webserver (Apache Httpd)

• "HTTPD Installation" : Installs Apache Httpd Software only when ansible_distribution is RedHat



- name: HTTPD Installation
  package: 
    name: "httpd"
    state: present
  when: ansible_distribution == "RedHat"



• "Web Page Setup" : Copies the web page from web directory in Controller Node to the Document Root in the Managed Node



- name: Web Page Setup
  template:
    dest: "/var/www/html"
    src: "web/index.html"



• "Starting HTTPD Service" : Starts Httpd Service



- name: Starting HTTPD Service
  service:
    name: "httpd"
    state: started
    enabled: yes

Complete Playbook

- hosts: loadbalancer
  vars_files:
    - vars.yml
  tasks:
  - name: Creation of directory to be mounted
    file:
      state: directory
      path: "{{ mount_directory }}"
      
  - name: Mounting directory created to CDROM
    mount:
      src: "/dev/cdrom"
      path: "{{ mount_directory }}"
      state: mounted
      fstype: "iso9660"
      
  - name: YUM Repository - AppStream
    yum_repository:
      baseurl: "{{ mount_directory }}/AppStream"
      name: "DVD1"
      description: "YUM Repository - AppStream"
      enabled: true
      gpgcheck: no
      
  - name: YUM Repository - BaseOS
    yum_repository:
      baseurl: "{{ mount_directory }}/BaseOS"
      name: "DVD2"
      description: "YUM Repository - BaseOS"
      enabled: true
      gpgcheck: no
      
  - name: Installation of HAProxy Software
    package:
      name: "haproxy"
      state: present
      
  - name: HAProxy Configuration File Setup
    template:
      dest: "/etc/haproxy/haproxy.cfg"
      src: "templates/haproxy.cfg"
    notify: Restart Load Balancer
    
  - name: Starting Load Balancer Service
    service:
      name: "haproxy"
      state: started
      enabled: yes
      
  - name: Stopping Firewall Service
    service:
      name: "firewalld"
      state: stopped
      enabled: yes
      
  - name: Setting SELinux Permissive
    selinux:
      policy: targeted
      state: permissive
      
handlers:
  - name: Restart Load Balancer
    systemd:
      name: "haproxy"
      state: restarted
      enabled: yes
      
      
- hosts: webserver
  vars_files:
    - vars.yml
  tasks:
  - name: Creation of directory to be mounted
    file:
      state: directory
      path: "{{ mount_directory }}"
      
  - name: Mounting directory created to CDROM
    mount:
      src: "/dev/cdrom"
      path: "{{ mount_directory }}"
      state: mounted
      fstype: "iso9660"
      
  - name: YUM Repository - AppStream
    yum_repository:
      baseurl: "{{ mount_directory }}/AppStream"
      name: "DVD1"
      description: "YUM Repository - AppStream"
      gpgcheck: no
      
  - name: YUM Repository - BaseOS
    yum_repository:
      baseurl: "{{ mount_directory }}/BaseOS"
      name: "DVD2"
      description: "YUM Repository - BaseOS"
      gpgcheck: no
      
  - name: HTTPD Installation
    package: 
      name: "httpd"
      state: present
    when: ansible_distribution == "RedHat"
    
  - name: Web Page Setup
    template:
      dest: "/var/www/html"
      src: "web/index.html"
      
  - name: Setting SELinux Permissive
    selinux:
      policy: targeted
      state: permissive
       
  - name: Stopping Firewall Service
    service:
      name: "firewalld"
      state: stopped
      enabled: yes
      
  - name: Starting HTTPD Service
    service:
      name: "httpd"
      state: started
      enabled: yes

---

Part 2 : Variable Files (vars.yml)

  mount_directory: "/dvd1"

---

Part 3 : Web Page (index.html)

  <body bgcolor='aqua'>
  <br><br>
  <b>IP Addresses</b> : "{{ ansible_all_ipv4_addresses }}"

Specifies Web Page that is accessed from Load Balancer’s IP Address

---

Part 4 : HAProxy Configuration File Template (haproxy.cfg)

#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   https://www.haproxy.org/download/1.8/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
# utilize system-wide crypto-policies
    ssl-default-bind-ciphers PROFILE=SYSTEM
    ssl-default-server-ciphers PROFILE=SYSTEM
#---------------------------------------------------------------------
# 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  hosts  in groups['webserver']  %}
    server  app1 {{ hosts }}:80 check
{% endfor %}

Jinja template and for loop specified above makes HAProxy configuration file more dynamic as it would add managed nodes specified under ‘webserver’ host dynamically.

---

Part 5 : Output

loadbalancer

HAProxy Configuration File after Ansible Playbook Execution-1

HAProxy Configuration File after Ansible Playbook Execution-2

HAProxy Configuration File after Ansible Playbook Execution-3

webserver

Webserver 1

Webserver 2

Output GIF

. . .

Thank You 😃

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