MongoError: Authentication failed with docker-compose

Question

I am trying to build this app https://github.com/dwgebler/node-express-example. I want to use it as a template for making a Mongodb http express server. I tried to build the docker compose file in this repo which looks like this (modified slightly):

version: "3.8"
services:
  database:
    image: mongo
    container_name: mongo-database
    restart: always
    volumes:
      - "mongodata:/data/db"
    ports:
      - "27017:27017"
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: example
  mongo-express:    
    image: mongo-express
    container_name: mongo-express
    restart: always
    ports:
      - "8081:8081"
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: example
      ME_CONFIG_MONGODB_SERVER: mongo-database
  web:
    image: node:16-alpine
    container_name: node-server
    restart: always
    user: "node"
    ports:
      - "9443:443"
    volumes:
      - "./app:/var/app/"
    working_dir: "/var/app"
    environment:
      NODE_ENV: dev
      DB_USER: root
      DB_PASSWORD: example
      DB_NAME: mongo-database
    command: "./wait.sh mongo-database 27017 'npm start'"
volumes:
  mongodata:

But when I run the command docker compose up -d in the same directory as the docker-compose.yml file, I get this in the "node-server" container logs:

Mongo started
MongoError: Authentication failed.
    at MessageStream.messageHandler (/var/app/node_modules/mongodb/lib/cmap/connection.js:272:20)
    at MessageStream.emit (node:events:513:28)
    at processIncomingData (/var/app/node_modules/mongodb/lib/cmap/message_stream.js:144:12)
    at MessageStream._write (/var/app/node_modules/mongodb/lib/cmap/message_stream.js:42:5)
    at writeOrBuffer (node:internal/streams/writable:391:12)
    at _write (node:internal/streams/writable:332:10)
    at MessageStream.Writable.write (node:internal/streams/writable:336:10)
    at Socket.ondata (node:internal/streams/readable:754:22)
    at Socket.emit (node:events:513:28)
    at addChunk (node:internal/streams/readable:315:12) {
  ok: 0,
  code: 18,
  codeName: 'AuthenticationFailed'
}

Why am I getting a MongoError: Authentication failed? Notice that I set

DB_USER: root
DB_PASSWORD: example
DB_NAME: mongo-database

In the web section of the docker file which matches the MONGO_INITDB_ROOT_USERNAME, MONGO_INITDB_ROOT_PASSWORD, from the database section and I set DB_NAME to mongo-database which matches the database section name. So why isn't it authenticating?

Try removing the volume in the Mongo container. The environment variables have 'INIT' in their names because they're only used when initializing a database. So if you already have a database in the volume you map, the variables aren't used. — Hans Kilian, Feb 02 '23 at 00:11
I tried, but I was unable to see the node-server logs in ./app — barrypicker, Feb 02 '23 at 01:11
See https://stackoverflow.com/questions/63754742/authentication-failure-while-trying-to-save-to-mongodb/63755470#63755470 — Wernfried Domscheit, Feb 02 '23 at 07:43

score 2 · Accepted Answer · answered Feb 02 '23 at 08:29

MONGO_INITDB_ROOT_USERNAME and PASSWORD create a user in the Mongo admin database. Your connection string tries to authenticate against the mongo-database database and it can't find the user. There are messages in the Mongo logs that tell you this.

To fix it, you need to authenticate against the admin database by adding authSource=admin to your connection string, like this

const uri = `mongodb://${process.env.DB_USER}:${process.env.DB_PASSWORD}@mongo-database/${process.env.DB_NAME}?retryWrites=true&writeConcern=majority&authSource=admin`;

MongoError: Authentication failed with docker-compose

1 Answers1