Mongo-express docker fails to connect to Mongo docker if DB volume is mounted

[ruslaniv]

I have this docker-compose file:

version: '3.7'
services:
  db-mongo:
    image: mongo
    container_name: db-mongo
  environment:
      - MONGO_INITDB_DATABASE=auth
      - MONGO_INITDB_ROOT_USERNAME=admin
      - MONGO_INITDB_ROOT_PASSWORD=pass
  volumes:
     - /Users/John/Documents/Docker/mongoDB/db-mongo:/data/db
   ports:
      - '27017:27017'
  db-mongo-admin:
    image: mongo-express
    container_name: db-mongo-admin
    depends_on:
      - db-mongo
    environment:
      - ME_CONFIG_MONGODB_SERVER=db-mongo
      - ME_CONFIG_MONGODB_ADMINUSERNAME=admin
      - ME_CONFIG_MONGODB_ADMINPASSWORD=pass
      - ME_CONFIG_BASICAUTH_USERNAME=admin
      - ME_CONFIG_BASICAUTH_PASSWORD=fairlylongpassword
    ports:
      - '8081:8081'

When i start it up, it fails with

...
Mon Jan 27 06:11:19 UTC 2020 retrying to connect to db-mongo:27017 (5/5)
/docker-entrypoint.sh: connect: Connection refused
/docker-entrypoint.sh: line 14: /dev/tcp/db-mongo/27017: Connection refused
Welcome to mongo-express
------------------------
/node_modules/mongodb/lib/server.js:265
        process.nextTick(function() { throw err; })
                                      ^
MongoError: failed to connect to server [db-mongo:27017] on first connect
...

But if I remove the bind mount from the Mongo container, without changing anything else, both containers start fine and I can use mongo-express to log to the DB.

[tianon]

This sounds like your MongoDB container is actually failing to start -- I don't think the shared directory provided by Docker Desktop / Docker for Mac OS to the Linux VM is going to be sufficient for what MongoDB expects to be able to do with that filesystem.

[akwanashie]

Having the same issue :-( My MongoDB container is running fine and other clients can connect to it without any issues. Did you find a fix for this @ruslaniv?

[mossad-zika]

completely useless with this kind of bugs

[ruslaniv]

Having the same issue :-( My MongoDB container is running fine and other clients can connect to it without any issues. Did you find a fix for this @ruslaniv?

Nope, could not fix it. Just had to use it without mounting external fs.

[chenjianjx]

I have exactly the same issue. According to the log, if volume is used, mongodb thinks it has started up 100% when it's actually just 90% started up, then mongo_express will try a connection right away, which will fail

mongodb_1  | {"t":{"$date":"2021-12-11T22:01:54.688+00:00"},"s":"I",  "c":"STORAGE",  "id":22430,   "ctx":"initandlisten","msg":"WiredTiger message","attr":{"message":"[1639260114:688810][1:0x7f1b253c6c80], txn-recover: [WT_VERB_RECOVERY_PROGRESS] Recovering log 2 through 2"}}

...
mongo-express_1  | Could not connect to database using connectionString: mongodb://mongodb:27017/"
...
mongodb_1  | {"t":{"$date":"2021-12-11T22:01:56.466+00:00"},"s":"I",  "c":"NETWORK",  "id":23015,   "ctx":"listener","msg":"Listening on","attr":{"address":"/tmp/mongodb-27017.sock"}}

And when you run docker-compose up mongo-express afterwards, it will connect.

I think the workaround may be letting mongo-express sleep for 5 seconds after mongodb thinks it's up, or retry the connection.

A quick fix: (sleep 5 seconds before exec)

  mongoui:
    image: mongo-express:latest
    ...
    depends_on:
      - mongodb
    entrypoint: [sh, -c, "sleep 5s && tini -- /docker-entrypoint.sh mongo-express"]

[chenjianjx]

Btw, why is wait_for_tcp() defined but not called in '/docker-entrypoint.sh' ?