Three-Tier Application Demo

Overview

A demo application with a three-tier architecture (Frontend → Backend → Database) designed to:

1. Show the capabilities of the cloud platform
2. Demonstrate how Network Policies work
3. Example of integration with Dex authentication system
4. Testing the interaction of components in a virtualized environment

Application Structure

• Project: demo-db
  • Database
    • VM: db (PostgreSQL)
• Project: demo-app
  • Frontend
    • VM: frontend (Bootstrap app)
    • Pod: frontend (Bootstrap app)
  • Backend
    • VM: backend-a (Flask + Gunicorn)
    • VM: backend-b (Flask + Gunicorn)

Component interaction is restricted by network policies. Application access requires authentication via Dex.

Access System

User	Role	Access Rights
demo-user@flant.com	Application User	Access via web interface
demo-db-admin@flant.com	Project Administrator demo-db	Full VM access with PostgreSQL
demo-app-admin@flant.com	Project Administrator demo-app	Management of all application components

Translated with DeepL.com (free version)

Repository Structure

• /apps - Frontend and backend source code
• /k8s - Kubernetes deployment manifests

Requirements

Make sure you install the following packages:

• task
• yq

Ensure the following d8 modules are enabled and configured:

• admission-policy-engine
• cni-cilium
• console
• multitenancy-manager
• service-with-healthchecks
• user-authn
• virtualization

Installation

1. Create a .env file with infrastructure settings:

STORAGE_CLASS=linstor-thin-r1
PASSWORD=password
FQDN=demo.example.com

2. Genereate ssh key to access VMs via ssh

task ssh-gen

3. Install APP

task deploy

4. Uninstall APP

task undeploy

How to connect to VM

Via SSH

d8 v ssh -n demo-app cloud@<vmname> -i ./tmp/demo --local-ssh

Via console

d8 v console -n demo-app <vmname>