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Prisma•2d ago
Satish

Coolify: MongoDB Replica Set

Does anybody have the "Custom MongoDB Configuration" to resolve the replica set issue?? Kindly help. Also, if I create replica set on my VPS(via Coolify), all the replica sets are in the same location, then whats the use of it??
1 Reply
Prisma AI Help
Prisma AI Help•2d ago
You opted for speed from this bot. Let's conjure up an answer right now! I understand you're having issues with MongoDB replica sets when using Prisma. Prisma requires MongoDB to be configured as a replica set because it uses transactions internally to avoid partial writes on nested queries, even if you're just running a single MongoDB instance. MongoDB Replica Set Configuration Options There are several ways to configure a MongoDB replica set for use with Prisma: 1. Using Docker Compose You can use a docker-compose configuration like this: 
version: "3.8"

services:
  mongo:
    image: mongo:7.0
    command: ["--replSet", "rs0", "--bind_ip_all", "--port", "27017"]
    ports:
      - 27017:27017
    extra_hosts:
      - "host.docker.internal:host-gateway"
    healthcheck:
      test: echo "try { rs.status() } catch (err) { rs.initiate({_id:'rs0',members:[{_id:0,host:'host.docker.internal:27017'}]}) }" | mongosh --port 27017 --quiet
      interval: 5s
      timeout: 30s
      start_period: 0s
      start_interval: 1s
      retries: 30
    volumes:
      - "mongo1_data:/data/db"
      - "mongo1_config:/data/configdb"

volumes:
  mongo1_data:
  mongo1_config:
version: "3.8"

services:
  mongo:
    image: mongo:7.0
    command: ["--replSet", "rs0", "--bind_ip_all", "--port", "27017"]
    ports:
      - 27017:27017
    extra_hosts:
      - "host.docker.internal:host-gateway"
    healthcheck:
      test: echo "try { rs.status() } catch (err) { rs.initiate({_id:'rs0',members:[{_id:0,host:'host.docker.internal:27017'}]}) }" | mongosh --port 27017 --quiet
      interval: 5s
      timeout: 30s
      start_period: 0s
      start_interval: 1s
      retries: 30
    volumes:
      - "mongo1_data:/data/db"
      - "mongo1_config:/data/configdb"

volumes:
  mongo1_data:
  mongo1_config:
The connection string would be: mongodb://127.0.0.1:27017/?replicaSet=rs0 GitHub Discussion 2. Using Bitnami MongoDB Image Another option is to use the Bitnami MongoDB image: 
version: '3.8'
services:
  
  database:
    image: 'bitnami/mongodb:latest'
    environment:
      - MONGODB_ADVERTISED_HOSTNAME=127.0.0.1
      - MONGODB_REPLICA_SET_MODE=primary
      - MONGODB_ROOT_USER=anyuser
      - MONGODB_ROOT_PASSWORD=anypassword
      - MONGODB_REPLICA_SET_KEY=replicasetkey123
    ports:
      - '27017:27017'
    volumes:
      - 'mongo-db:/bitnami/mongodb'

volumes:
  mongo-db:
version: '3.8'
services:
  
  database:
    image: 'bitnami/mongodb:latest'
    environment:
      - MONGODB_ADVERTISED_HOSTNAME=127.0.0.1
      - MONGODB_REPLICA_SET_MODE=primary
      - MONGODB_ROOT_USER=anyuser
      - MONGODB_ROOT_PASSWORD=anypassword
      - MONGODB_REPLICA_SET_KEY=replicasetkey123
    ports:
      - '27017:27017'
    volumes:
      - 'mongo-db:/bitnami/mongodb'

volumes:
  mongo-db:
For this setup, you might need to use a connection string with directConnection=true: mongodb://<USER>:<PASSWORD>@<HOST>:<PORT>/<DATABASE>?authSource=admin&directConnection=true [GitHub Issue](https://github. com/prisma/prisma/issues/8266) 3. Configuring an Existing MongoDB Installation If you're using a standalone MongoDB installation, you can modify the MongoDB config file: 
replication:
  replSetName: "rs0"
replication:
  replSetName: "rs0"
After updating the config, restart MongoDB and initialize the replica set: 
rs.initiate({_id: 'rs0', members: [{_id: 0, host: 'localhost:27017'}]});
rs.initiate({_id: 'rs0', members: [{_id: 0, host: 'localhost:27017'}]});
Regarding Your Second Question Even though all replica set members are in the same location on your VPS, there are still benefits: 1. Prisma requires transactions which only work with replica sets in MongoDB 2. It provides a configuration that matches production environments, avoiding surprises when deploying 3. It enables features like transactions that wouldn't be available in standalone mode The primary purpose in development is to satisfy Prisma's requirement for transactions, not necessarily for the high availability benefits that replica sets typically provide in production. If you're finding this setup cumbersome, note that many developers in the Prisma community have expressed similar concerns, but currently, this requirement cannot be disabled in Prisma when using MongoDB. Hope this helps with your Coolify setup!

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