Cannot connect to MongoDB in docker

Question

Using the official mongo image from the docker hub, I run the following command to get it running:

docker run --name api -p 127.0.0.1:27017:27017 -p 127.0.0.1:28017:28017 -d mongo

Then from another terminal shell, I run mongo

However, I keep getting the following error:

MongoDB shell version: 3.2.3
connecting to: test
2016-02-18T13:52:08.110-0700 I NETWORK  [thread1] Socket recv() errno:104 Connection reset by peer 127.0.0.1:27017
2016-02-18T13:52:08.110-0700 I NETWORK  [thread1] SocketException: remote: (NONE):0 error: 9001 socket exception [RECV_ERROR] server [127.0.0.1:27017] 
2016-02-18T13:52:08.110-0700 E QUERY    [thread1] Error: network error while attempting to run command 'isMaster' on host '127.0.0.1:27017'  :
connect@src/mongo/shell/mongo.js:224:14
@(connect):1:6

exception: connect failed

I checked the logs for the container, and everything seemed right:

2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] MongoDB starting : pid=1 port=27017 dbpath=/data/db 64-bit host=73334e5089e1
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] db version v3.2.3
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] git version: b326ba837cf6f49d65c2f85e1b70f6f31ece7937
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] OpenSSL version: OpenSSL 1.0.1e 11 Feb 2013
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] allocator: tcmalloc
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] modules: none
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] build environment:
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten]     distmod: debian71
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten]     distarch: x86_64
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten]     target_arch: x86_64
2016-02-18T20:51:20.538+0000 I CONTROL  [initandlisten] options: {}
2016-02-18T20:51:20.542+0000 I STORAGE  [initandlisten] wiredtiger_open config: create,cache_size=8G,session_max=20000,eviction=(threads_max=4),config_base=false,statistics=(fast),log=(enabled=true,archive=true,path=journal,compressor=snappy),file_manager=(close_idle_time=100000),checkpoint=(wait=60,log_size=2GB),statistics_log=(wait=0),
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] 
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] 
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2016-02-18T20:51:20.615+0000 I CONTROL  [initandlisten] 
2016-02-18T20:51:20.616+0000 I FTDC     [initandlisten] Initializing full-time diagnostic data capture with directory '/data/db/diagnostic.data'
2016-02-18T20:51:20.616+0000 I NETWORK  [HostnameCanonicalizationWorker] Starting hostname canonicalization worker
2016-02-18T20:51:20.633+0000 I NETWORK  [initandlisten] waiting for connections on port 27017

What's wrong with docker or Mongo? I've searched everywhere for an answer, and nothing has worked so far. Is docker or Mongo broken?

Edit: I did a little more investigation, and I found that I cannot access the internet from inside the container. I connect to it by running docker exec -ti api /bin/bash and then try to ping google or something, and the command just hangs.

I can only seem to get an internet connection from the container to the outside world by using --net=host in the docker run command.

Solution 1

You have to tell the container to use it's own IP Address instead of localhost.

For example, let's assume you generated scaffold code with expressjs, you have to write in routes/index.js

var mongodb = require('mongodb');
router.get('/thelist', function(req, res){

  // Get a Mongo client to work with the Mongo server
  var MongoClient = mongodb.MongoClient;

  // Define where the MongoDB server is
  var url = 'mongodb://172.17.0.5:27017/dbname';

  // Connect to the server
  MongoClient.connect(url, function (err, db) {
  .........

where 172.17.0.5 is the $CONTAINER_IP

you can find the container ip via $ docker inspect $CONTAINER_NAME | grep IPAddress

If no internet in container

Open with sudo sudo vim /etc/NetworkManager/NetworkManager.conf and comment out the line dns=dnsmasq, so you would now have:

[main]                        
plugins=ifupdown,keyfile,ofono
#dns=dnsmasq                  

[ifupdown]                    
managed=false                 

Edit: service name instead of IP

You may now use service name instead of IP Address of the container, eg:

  // Define where the MongoDB server is
  var url = 'mongodb://api:27017/dbname';

Solution 2

The gotcha here is - if a container listens on 127.0.0.1, then the host can't map ports to it.

You need to listen on 0.0.0.0 or similar, and then the -p can reach the container's interface.

Solution 3

I had the same problem but found another way to address this issue. You can just pass network parameter while running docker image and this way docker points to correct localhost.

docker run --network="host" ....

Source for this solution

Comments

[Ben Reeves]

This may not help, but I noticed in the mongo client error message that it said network error while attempting to run command 'isMaster' on host '127.0.0.1:27017'. Perhaps this is a permission error?

[wheeler]

It turned out to be a docker networking issue with docker and my VPN client conflicting with each other.

[wheeler]

So you mean modify the docker run command to be docker run --name mongo -p 0.0.0.0:27017:27017 -p 0.0.0.0:28017:28017 -d mongo instead? If so, that doesn't change anything, I still cannot connect to the container using the mongo shell.

[wheeler]

That didn't work, but what did work was disabling dnsmasq on the host.

[Saúl Martínez Vidals]

this worked for me, I just commented the line bindIp: under the net: section, thank you !

[rezwits]

api:27017, uri scheme for the win...

[technazi]

What is a service name?

[Daniel Andrei Mincă]

this is a service name

[Timothy Pulliam]

How would you know that container IP ahead of time? Say, if you wanted to put this in a Dockerfile?

[Daniel Andrei Mincă]

You don't. The IPs are assigned automatically by default from a class C range. You can a) get the IP after container is up via docker inspect <container>; or b) start a container with static IP address assigned - requires creating a docker network, there's alot on this over the Internet.