MongoDB running but can't connect using shell

Question

CentOS 5.x Linux with MongoDB 2.0.1 (tried main and legacy-static)

MongoDB is running:

root     31664  1.5  1.4  81848 11148 ?        Sl   18:40   0:00 ./mongod -f mongo.conf -vvvvv --fork

Using a simple shell connect to get to the server fails:

[root@xxxx bin]# ./mongo
MongoDB shell version: 2.0.1
connecting to: test
Mon Oct 31 18:41:32 Error: couldn't connect to server 127.0.0.1 shell/mongo.js:84
exception: connect failed

The web interface on port 28017 loads fine, as does using the MongoDB shell from a remote Linux host. Can also telnet to localhost:27017, which means no ports are blocked. There is no SELinux running on this machine as well. I have also tried explicitly specifying localhost:2017/db to no avail.

$ ./mongo remote-ip:27017
MongoDB shell version: 2.0.1
connecting to: remote-ip:27017/test
> show dbs
local   0.03125GB
>

Logs are completely mum on the subject:

.....
Mon Oct 31 18:40:34 [initandlisten] fd limit hard:1024 soft:1024 max conn: 819
Mon Oct 31 18:40:34 [initandlisten] waiting for connections on port 27017
Mon Oct 31 18:40:34 BackgroundJob starting: snapshot
Mon Oct 31 18:40:34 BackgroundJob starting: ClientCursorMonitor
Mon Oct 31 18:40:34 BackgroundJob starting: PeriodicTask::Runner
Mon Oct 31 18:40:34 [websvr] fd limit hard:1024 soft:1024 max conn: 819
Mon Oct 31 18:40:34 [websvr] admin web console waiting for connections on port 28017

Stracing the mongo shell client shows only one problematic call:

[pid 31708] connect(4, {sa_family=AF_INET, sin_port=htons(27017), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EBADF (Bad file descriptor)

Filesystem is clean, no ulimit restrictions (running as root for testing). I can see from the strace that the mongo client is trying to connect via TCP (AF_INET), but since it is local and MongoDB creates a file socket, is there a way to tell the client to connect through that instead? Or better yet, why would the client be throwing a EBADF?

EDIT: My basic Mongo conf:

dbpath=/root/mongodb-linux-i686-2.0.1/data
logpath=/root/mongodb-linux-i686-2.0.1/logs/mongo.log
slowms=15
rest=1

Answer 1

I had this problem as well. Is your MongoDB journaling? I noticed the following "preallocate" entries in the log file. Once I saw the last line "waiting for connections on port", I could connect. Notice that this "faster" mode took 12 minutes to intialize.

William

Tue Apr 17 16:48:01 [initandlisten] MongoDB starting : pid=2248 port=27017 dbpath=E:\MongoData 64-bit host=ME
Tue Apr 17 16:48:01 [initandlisten] db version v2.0.0-rc0, pdfile version 4.5
Tue Apr 17 16:48:01 [initandlisten] git version: 8d4bf50111352cee5a4f1abf25b63442d6c45dc4
Tue Apr 17 16:48:01 [initandlisten] build info: windows (6, 1, 7601, 2, 'Service Pack 1') BOOST_LIB_VERSION=1_42
Tue Apr 17 16:48:01 [initandlisten] options: { bind_ip: "ip", dbpath: "E:\MongoData", directoryperdb: true, journal: true, logpath: "E:\MongoData\mongo.log", quiet: true, rest: true, service: true }
Tue Apr 17 16:48:01 [initandlisten] journal dir=E:/MongoData/journal
Tue Apr 17 16:48:01 [initandlisten] recover : no journal files present, no recovery needed
Tue Apr 17 16:48:02 [initandlisten] preallocateIsFaster=true 9.68
Tue Apr 17 16:48:04 [initandlisten] preallocateIsFaster=true 8.44
Tue Apr 17 16:48:06 [initandlisten] preallocateIsFaster=true 9.68
Tue Apr 17 16:48:06 [initandlisten] preallocateIsFaster check took 4.921 secs
Tue Apr 17 16:48:06 [initandlisten] preallocating a journal file E:/MongoData/journal/prealloc.0
Tue Apr 17 16:52:37 [initandlisten] preallocating a journal file E:/MongoData/journal/prealloc.1
Tue Apr 17 16:56:54 [initandlisten] preallocating a journal file E:/MongoData/journal/prealloc.2
Tue Apr 17 17:01:42 [initandlisten] waiting for connections on port 27017
Tue Apr 17 17:01:42 [websvr] admin web console waiting for connections on port 28017

Answer 2

I had same problem. In my case MongoDB server wasn't running.

Try to open this in your web browser:

http://localhost:28017

If you can't, this means that you have to start MongoDB server.

Run mongod in another terminal tab. Then in your main tab run mongo which is is the shell that connects to your MongoDB server.

Answer 3

I don't see this having an accepted answer yet, so I'll just add my 2 cents.

I had the exact same issue just now. After a while I realized I've locked localhost out in my iptables rules. So, check your firewall.

Answer 4

I think there is some default config what is missing in this version of mongoDb client. Try to run:

mongo 127.0.0.1:27017

It's strange, but then I've experienced the issue went away :) (so the simple command 'mongo' w/o any params started to work again for me)

[Ubuntu Linux 11.10 x64 / MongoDB 2.0.1]