MongoDB (Replica Set with Auto initialization)

This is a MongoDB template with Replica Set mode enabled by default.

Features

• Replica Set (rs0) enabled
• Automatic replica set initialization on first boot
• Compatible with existing Zeabur MongoDB environment variables
• Compatible with MongoDB Compass and mongosh

Connection

Use the connection string displayed in Zeabur's Connections tab:

mongodb://${MONGO_USERNAME}:${MONGO_PASSWORD}@${PORT_FORWARDED_HOSTNAME}:${DATABASE_PORT_FORWARDED_PORT}/?directConnection=true&authSource=admin

Why Replica Set?

A single-node replica set unlocks:

• Change streams
• Transactions
• Causal consistency
• Required by many frameworks (e.g., Prisma, Mongoose transactions)

auto-init logic

On boot:

1. MongoDB starts with --replSet rs0
2. Script checks if RS exists
3. If not → rs.initiate(...)
4. Ensures idempotent redeploys