SocketException: Address already in use MONGODB

You can kill the previous mongod instance and start the new one.

To kill the previous mongod instance, first search for a list of tasks running on your machine by typing,

sudo lsof -iTCP -sTCP:LISTEN -n -P

Search for mongod COMMAND and its PID and type,

sudo kill <mongo_command_pid>

Now start your mongod instance by typing,

mongod

You can see MongoDB running successfully.

You already have a process running in the port 27017 which is used by mongodb. So either you need to stop the process in that port or try with different port number.

Try mongod --port 27018

You can change the port number of your choice.

EDIT:

You can also just stop all the running instances of mongo server using sudo killall mongod as mentioned by @Dassi Orleando in the comments. And run mongod

Summary other(@Tony Roczz, @Balasubramani M) answer to here:

Root Cause

error: Failed to set up listener: SocketException: Address already in use

means:

• previously have run mongodb
  • probably use default port 27017

Solution

(most case) kill and restart mongod

kill mongod

two method:

• use killall
  • killall mongod
• kill by PID
  • find mongod PID
    • method 1: ps aux | grep mongod
    • output can see like this: limao 425 ... /usr/local/opt/mongodb-community/bin/mongod --config /usr/local/etc/mongod.conf
    • method 2: lsof -iTCP -sTCP:LISTEN -n -P
    • output can see like this: mongod 425 limao .. TCP 127.0.0.1:27017 (LISTEN)
  • kill by PID: kill -9 425

re-start mongod

• most case: mongod
• some special case
  • brew services start mongodb-community
    • for install community version in Mac by: brew install mongodb-community

(for some people) run with another port

• run with another port: mongod --port 27018
  • only for those want to run multiple mongod server same time

Additional Note

which port the running mongodb is using?

 lsof -iTCP -sTCP:LISTEN -n -P
COMMAND     PID  USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mongod      425 limao   10u  IPv4 0xab744305e75263cf      0t0  TCP 127.0.0.1:27017 (LISTEN)

can see 27017 is current running mongodb port.

how to check / make sure mongod is running

• check mongod status:
  • ps aux | grep mongod
    • output can see mongod service
  • brew services list
    • if installed by brew and start by brew

if you're using mongodb version 4.*

in default settings, there should be a "db" folder "/data/db" having the necessary permission.

to check it the MongoDB service started

brew services list

if not then run

brew services start mongodb

run mongo instead of mongod

I solved it pasting the command below into the command line in order to close mongo's server.

sudo pkill -f mongod

"sudo" (Super User Do) runs the command admin permissions, so it will ask you for your user password