⛔MongoDB Transactions Error: "Transaction numbers are only allowed on a replica set member or mongos

If you're using Transaction rollback with Mongoose in a Node.js application and encounter the error "Transaction numbers are only allowed on a replica set member or mongos".

Reasons for the Error 🤔:

1. Local MongoDB is not a Replica Set.
2. Standalone MongoDB Instance: By default, MongoDB in a standalone configuration does not support multi-document transactions.
3. Missing Transaction Support: Transactions are only available in replica set members or in clusters managed by mongos (sharded MongoDB).

🖥️ Solution Steps (On Windows):

✅ stop your mongodb service and edit the C:\Program Files\MongoDB\Server{version}\bin\mongod.cfg file

# ⏹️ stop the service
net stop MongoDB

# 📝 edit below file
C:\Program Files\MongoDB\Server\{version}\bin\mongod.cfg

# set replica 
replication:
  replSetName: "rs0" # any name can set

#  🔄 start the service

net start MongoDB

# 🔧 open mongo SHell  & init the the rs

rs.initiate()

# check the status
rs.status()

🐧Solution Steps (On Linux/Ubuntu server):

#⏹️  mongodb service stop
sudo service mongod stop

#🔧 access the mongod.config
 sudo chmod -R 777 /etc/mongod.conf

#edit the cofigurationh
 nano /etc/mongod.conf

 #add now

# 🔧 Mongo db replica for Mongoose Transaction rollback.

replication:
  replSetName: "rs0"

 #  🔄 start the service
 sudo service mongod start


# now go to mongo shell
mongosh

# now update the 
rs.initiate()

# verify  status

 rs.status()

 # start the mongod

 sudo service mongod start

🎯 Conclusion:

By following these steps, you'll be able to fix the "Transaction numbers are only allowed on a replica set member or mongos" error and leverage MongoDB transactions effectively in your Node.js application on Windows or Linux.