"UserNotFound" error when connecting to mongodb in docker compose

Question

I’m trying to set up a mongodb instance using docker compose, but I'm running into an authentication issue. here’s my docker-compose.yml file:

version: '3.9'
services:
  mongo:
    image: mongo:latest
    restart: always
    container_name: mongodb
    ports:
      - '27017:27017'
    volumes:
      - mongodb:/data/db
    environment:
       MONGO_INITDB_ROOT_USERNAME: eagle
       MONGO_INITDB_ROOT_PASSWORD: 123
       MONGO_INITDB_DATABASE: DB

volumes:
  mongodb: {}

when I try to connect, I get the following error in the logs:

{"t":{"$date":"2024-10-20T00:16:43.975+00:00"},
 "s":"I",
 "c":"ACCESS",
 "id":5286307,
 "ctx":"conn13",
 "msg":"Failed to authenticate",
 "attr":{
   "client":"172.19.0.1:49014",
   "isSpeculative":true,
   "isClusterMember":false,
   "mechanism":"SCRAM-SHA-256",
   "user":"eagle",
   "db":"DB",
   "error":"UserNotFound: Could not find user \"eagle\" for db \"DB\"",
   "result":11,
   "metrics":{
     "conversation_duration":{
       "micros":271,
       "summary":{
         "0":{
           "step":1,
           "step_total":2,
           "duration_micros":245
         }
       }
     },
     "extraInfo":{}
   }
 }
}
{"t":{"$date":"2024-10-20T00:16:43.976+00:00"},
 "s":"I",
 "c":"ACCESS",
 "id":6788604,
 "ctx":"conn13",
 "msg":"Auth metrics report",
 "attr":{
   "metric":"acquireUser",
   "micros":0
 }
}

My user "eagle" could not be found for the database "DB." I’ve double-checked the environment variables, and they seem correct.

This connection string should work: mongodb://eagle:123@localhost:27017/DB, but in Datagrid I get this error when I try to connect:

com.mongodb.MongoSecurityException: Exception authenticating MongoCredential{mechanism=SCRAM-SHA-1, userName='eagle', source='DB', password= , mechanismProperties= }

Any insights on how to resolve it would be appreciated!

Answer 1

MONGO_INITDB_DATABASE specifies the context for the init scripts, it has nothing to do with the root user.

MONGO_INITDB_ROOT_USERNAME is created in admin database.

As @ray alluded, you have to specify auth database in the command line options. mongosh syntax is --authenticationDatabase=admin so the whole command would be

mongosh -u eagle -p 123 --authenticationDatabase=admin mongodb://localhost:27017/DB

or you can rely on defaults:

mongosh -u eagle -p 123

The last command will log you into test database, so you will need to use DB to switch to DB database.