mongo - couldn't connect to server 127.0.0.1:27017

Question

I am coming from riak and redis where I never had an issue with this services starting, or to interact.

This is a pervasive problem with mongo and am rather clueless

Answer 1

To connect with mongo we have to first start 'mongod' services. following output you can see :

$ mongod
2017-03-05T00:31:39.055+0530 I CONTROL  [initandlisten] MongoDB starting : pid=1481 port=27017 dbpath=/data/db 64-bit host=Prabhu-Nandans-Mac.local
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] db version v3.4.2
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] git version: 3f76e40c105fc223b3e5aac3e20dcd026b83b38b
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] OpenSSL version: OpenSSL 1.0.2k  26 Jan 2017
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] allocator: system
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] modules: none
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] build environment:
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten]     distarch: x86_64
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten]     target_arch: x86_64
2017-03-05T00:31:39.056+0530 I CONTROL  [initandlisten] options: {}
2017-03-05T00:31:39.056+0530 W -        [initandlisten] Detected unclean shutdown - /data/db/mongod.lock is not empty.
2017-03-05T00:31:39.057+0530 I -        [initandlisten] Detected data files in /data/db created by the 'wiredTiger' storage engine, so setting the active storage engine to 'wiredTiger'.
2017-03-05T00:31:39.057+0530 W STORAGE  [initandlisten] Recovering data from the last clean checkpoint.
2017-03-05T00:31:39.057+0530 I STORAGE  [initandlisten] wiredtiger_open config: create,cache_size=3584M,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),
2017-03-05T00:31:39.620+0530 I CONTROL  [initandlisten] 
2017-03-05T00:31:39.620+0530 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2017-03-05T00:31:39.620+0530 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2017-03-05T00:31:39.620+0530 I CONTROL  [initandlisten] 
2017-03-05T00:31:39.620+0530 I CONTROL  [initandlisten] 
2017-03-05T00:31:39.620+0530 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000
2017-03-05T00:31:39.643+0530 I FTDC     [initandlisten] Initializing full-time diagnostic data capture with directory '/data/db/diagnostic.data'
2017-03-05T00:31:39.643+0530 I NETWORK  [thread1] waiting for connections on port 27017
2017-03-05T00:31:40.008+0530 I FTDC     [ftdc] Unclean full-time diagnostic data capture shutdown detected, found interim file, some metrics may have been lost. OK
2017-03-05T00:32:03.832+0530 I NETWORK  [thread1] connection accepted from 127.0.0.1:49806 #1 (1 connection now open)
2017-03-05T00:32:03.833+0530 I NETWORK  [conn1] received client metadata from 127.0.0.1:49806 conn1: { application: { name: "MongoDB Shell" }, driver: { name: "MongoDB Internal Client", version: "3.4.2" }, os: { type: "Darwin", name: "Mac OS X", architecture: "x86_64", version: "16.4.0" } }
2017-03-05T00:32:08.376+0530 I -        [conn1] end connection 127.0.0.1:49806 (1 connection now open)

After that open another terminal and just type 'mongo'.

Following is output you can see :

$ mongo
MongoDB shell version v3.4.2
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.2

Your issue solved :)

Answer 2

You can try with following command:

sudo service mongod start

Answer 3

Resolved.

This problem could be solved by the below mentioned 4 steps

1) Remove .lock file

sudo rm /var/lib/mongodb/mongod.lock 

2) repair the mongodb

mongod -–repair

3) start the mongod server

sudo service mongod start 

4) start the mongo client

mongo

For more details take a look at http://shakthydoss.com/error-couldnt-connect-to-server-127-0-0-127017-srcmongoshellmongo-js-exception-connect-failed/

http://shakthydoss.com/technical/error-couldnt-connect-to-server-127-0-0-127017-srcmongoshellmongo-js-exception-connect-failed/

Answer 4

Normally this caused because you didn't start mongod process before you try starting mongo shell.

Start mongod server

mongod

Open another terminal window

Start mongo shell

mongo

Answer 5

This method only works if you want to repair your data files without preserving the original files

To find where you dbpath resides- vim /etc/mongodb.conf

check for option dbpath=

(I have dbpath=/var/lib/mongodb)

Default: /data/db/

Typical locations include: /srv/mongodb, /var/lib/mongodb or /opt/mongodb .

Replace the /var/lib/mongodb with your dbpath

sudo rm /var/lib/mongodb/mongod.lock
sudo mongod --dbpath /var/lib/mongodb/ --repair
sudo mongod --dbpath /var/lib/mongodb/ --journal

(Make sure that you leave you terminal running in which you have run above lines, dont press 'Ctrl+c' or quit it.) Type the command to start mongo now in another window.

Hope this works for you ! for those who want to repair your data files while preserving the original files mongo recover

Answer 6

I had same problem to connect mongodb after install using brew on macOS.

The problem was also mongod.lock but before i had mongodb 3.6 installed and database directory was /usr/local/var/mongodb and it have old files and mongod.lock

Simple i moved my old database files to different folder and removed everything from /usr/local/var/mongodb

Then restarted :

brew services restart mongodb

And it's working fine now.