VLAN

Enable private networking between Discloud applications using VLAN and HOSTNAME in discloud.config.

🧾 Overview

The VLAN feature lets multiple Discloud applications communicate over an isolated private network (container-to-container) without exposing internal services publicly. Typical scenarios:

Service	Purpose	Example
Backend API	Business logic	api app calling database
Database	Persistent storage	MongoDB / PostgreSQL template or container
Cache	Low-latency data	Redis instance

Traffic stays within the Discloud infrastructure. No public ingress is created for services accessed only via the private hostname.

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⚙️ Configuration (discloud.config)

Add the following keys to each application that should participate in the private network:

discloud.config

NAME=My Mongo Server
VLAN=true
HOSTNAME=mymongoserver
#       |      ^     |
#       |      Private network name for this application

Key	Required	Description
VLAN	Yes	Enables private networking for the application
HOSTNAME	Recommended	Custom hostname alias for other apps to reach this one

If two apps set the same HOSTNAME, behavior is undefined. Keep hostnames unique and lowercase (letters, digits, hyphens).

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🧷 Example: MongoDB Service + Backend

Service app:

discloud.config

NAME=Mongo Service
VLAN=true
HOSTNAME=mymongoserver

Backend connection code:

TypeScript

import mongoose from 'mongoose';

const uri = 'mongodb://mymongoserver:27017/mydatabase';
//                            ^
//                            HOSTNAME from Mongo service app

async function main() {
    try {
        await mongoose.connect(uri);
        console.log('Connected to MongoDB successfully');
    } catch (error) {
        console.error('MongoDB connection error:', error);
        process.exit(1);
    }
}

main();

Node (Native Driver)

import { MongoClient } from 'mongodb';
const uri = 'mongodb://mymongoserver:27017/mydatabase';
const client = new MongoClient(uri);
await client.connect();
console.log('Ping:', await client.db().command({ ping: 1 }));

Python

from pymongo import MongoClient
client = MongoClient('mongodb://mymongoserver:27017/mydatabase')
print(client.admin.command('ping'))

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🧵 Hostname Conventions

Rule	Recommendation
Characters	a-z 0-9 - only
Length	1–25 chars

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🛡️ Security Notes

Aspect	Detail
Isolation	Only apps you deploy with VLAN enabled can reach each other
Exposure	No automatic public port publishing
Secrets	Still store credentials via environment variables
Principle	Disable VLAN on apps that do not need internal reachability

Combine VLAN with environment-scoped credentials for least privilege.