'Failed to unlink socket file" error in MongoDB 3.0

80
votes

I am new to MongoDB. I am trying to install MongoDb 3.0 on Ubuntu 13.0 LTS, which is a VM on Windows 7 Host. I have installed MongoDB successfully (packages etc.), but when I execute the command sudo service mongod start, I get the following error in the "/var/log/mongodb/mongod.log" log file. Can anyone help me understanding this error. There is nothing on internet related to this.

2015-04-23T00:12:00.876-0400 I CONTROL ***** SERVER RESTARTED ***** 2015-04-23T00:12:00.931-0400 E NETWORK [initandlisten] Failed to unlink socket file /tmp/mongodb-27017.sock errno:1 Operation not permitted 2015-04-23T00:12:00.931-0400 I - [initandlisten] Fatal Assertion 28578 2015-04-23T00:12:00.931-0400 I - [initandlisten]

9
mongodbubuntu-13.04
This is a question better suited for DBA StackExchange, but hopefully it should be moved there by moderators :). Can you include the output of ls -lat /tmp/mongodb-27017.sock? I suspect you may have started mongod as a different user (perhaps root) rather than starting with the service (which should use the mongodb user). You should be able to fix this by stopping the mongod service, sudo rm /tmp/mongodb-27017.sock, and then starting the service again. The error here is fairly benign, unless you want to connect to mongod over a domain socket instead of via a TCP/IP connection. – Stennie
I have fixed this issue myself, by deleting the 'mongodb-27017.sock' file . I ran the service after deleting this file, which worked fine. However, I am still not sure the root cause of the issue. The output of the command 'ls - lat /tmp/mongodb-27017.sock' is 'srwx------ 1 mongodb nogroup 0 Apr 23 06:24 /tmp/mongodb-27017.sock'. – KurioZ7
stackoverflow.com/a/38843534/1773972 They suggested changing permission of that file, and it tested on ubuntu 16.04 and worked for me ! – Pini Cheyni

9 Answers

155
votes

I have fixed this issue myself, by deleting the mongodb-27017.sock file . I ran the service after deleting this file, which worked fine. However, I am still not sure the root cause of the issue. The output of the command ls - lat /tmp/mongodb-27017.sock is now

srwx------ 1 mongodb nogroup 0 Apr 23 06:24 /tmp/mongodb-27017.sock
45
votes

Alternative to the answer provided by KurioZ7, you can simply set the permissions of the .sock file to the current user:

sudo chown `whoami` /tmp/mongodb-27017.sock

This does the trick for me if I want to run mongod without sudo. If I delete the file like in KurioZ7s answer, I will simply get the same error the next time I restart my machine.

31
votes

This issue occurs when you use the command 

mongod

Before using the command

sudo service mongod start

To fix the issue, either:

Set appropriate permissions on the file:

/tmp/mongodb-27017.sock

OR

Remove the file

/tmp/mongodb-27017.sock

Run 

sudo service mongod start && mongod
12
votes

The most likely cause for this was that the mongod process was at some point started by the root user. The socket file (/tmp/mongodb-27017.sock) was therefore owned by the root user. The mongod process usually runs under its own dedicated user, and that user did not have the permissions to delete that file.

The solution, as you already found out, was to delete it. Then mongodb was able to recreate it with the correct permissions. This should persist after reboot, as long as mongodb is started using the init scripts, or under the correct user account.

8
votes
$ sudo mongod

it solve problem for me

3
votes

For UNIX-based operating systems, as an alternative to the answer provided by Bastronaut, you could also specify the .sock file to be saved to a folder over which mongod has full user rights (corresponding to the way you are running mongod), that way mongod will also be able to remove the .sock file upon shutdown. The default folder to which the .sock file is saved is '/tmp'. To specify another folder, use a custom mongodb configuration file, for instance 'mongodb.conf', and add the following to it:

net:
  unixDomainSocket:
    pathPrefix: "anotherFolder"

After which you can run mongod with the command:

$ mongod --config /path/to/mongodb.conf

You can read the documentation on: https://docs.mongodb.org/manual/reference/configuration-options/#net.unixDomainSocket.pathPrefix

2
votes

Change the ownership mongodb-27017.sock file in /tmp directory and start the mongod again. 

cd /tmp


sudo chown mongodb:mongodb mongodb-27017.sock

sudo systemctl start mongod
1
votes

Manually restarting mongod service after restart fixed the problem.

Long-term solution was to add static host name, instead of ip address 'net' part of mongod.conf file (I suspect the problem is that ip address is not yet given to server, when mongod servis starts).

0
votes

If you are having this problem using docker, refer to this question:

MongoDB docker container “Failed to unlink socket file”