Webservers Pool

1. Introduction

The webservers pool is the public (internet) entry point of the infrastructure. These are replicated servers with the same functions.
These servers interface with two networks: the internet service provider's network and the cluster-gateway network.
These machines do not have direct access to the main network of the proto box (box-network) for security reasons.
These internet servers receive requests from the internet and then forward them to the proxy servers (gateway-pool).

Position in the infrastructure:

2. Roles

The webservers primarily have three functions:

• Application server with Nginx
• Management and renewal of the certificate used with Certbot and Let's Encrypt
• Routing to the internet with Netplan

3. Networking

This group interfaces with two networks:

• public-network
  For routing traffic to the internet.
• gateway-network
  For accessing cluster services.

4. Volumes

The webserver group has a shared volume that allows sharing configuration files such as:

• Certificates
• Nginx configurations

5. High Availability

High availability is essential at this level, and any point of failure must be excluded.
For this, two floating IPs are created:

• public-floatingIP: Used to replicate the IP for incoming requests.
• private-floatingIP: Manages the replication of the internal IP (cluster-gateway) to route outgoing traffic with high availability.

6. Security

The security of this group is primarily based on:

• iptables:
  • Incoming ports:
    • 80
    • 443
• Certificates

7. Applications

• Nginx as the application server.
• Certbot for certificate management.
• KeepAlived for floating IPs.
• GlusterFS for clustering volumes.

8. Installation

The installation of these servers is automated by the framework. They only need to be assigned in the group vars of the webservers_pool.

    webservers_pool:
      vars:
        output_interface: public-gateway
        input_interface: cluster-gateway
        # Declaration of floating IPs
        vips:
          # internet-floatingIP
          public-gateway:
            virtual_router_id: 1
            vip: 192.168.0.33
          # internal-floatingIP
          cluster-gateway:
            virtual_router_id: 2
            vip: 192.168.2.254
      hosts:
        webserver-1:
          public-gateway:
            # used for configuring KeepAlived
            priority: 200
            state: MASTER
          cluster-gateway:
            # used for configuring KeepAlived
            priority: 100
            state: BACKUP
        webserver-2:
          public-gateway:
            # used for configuring KeepAlived
            priority: 100
            state: BACKUP
          cluster-gateway:
            # used for configuring KeepAlived
            priority: 200
            state: MASTER

9. Summary

Application	Status
Installation and commissioning	DONE
Nginx	DONE
Certbot	DONE
Keepalived	DONE
GlusterFS	TODO