Rails: Address already in use - bind(2) (Errno::EADDRINUSE)

Question

You need to use kill -9 59780 with 59780 replaced with found PID number (use lsof -wni tcp:3000 to see which process used 3000 port and get the process PID).

Or you can just modify your puma config change the tcp port tcp://127.0.0.1:3000 from 3000 to 9292 or other port that not been used.

Or you can start your rails app by using:

bundle exec puma -C config/puma.rb -b tcp://127.0.0.1:3001

To kill the puma process first run

    lsof -wni tcp:3000 

to show what is using port 3000. Then use the PID that comes with the result to run the kill process.

For example after running lsof -wni tcp:3000 you might get something like

    COMMAND  PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
    ruby    3366 dummy    8u  IPv4  16901      0t0  TCP 127.0.0.1:3000 (LISTEN)

Now run the following to kill the process. (where 3366 is the PID)

kill -9 3366

Should resolve the issue

you can also try this trick:

ps aux | grep puma

sample output:

myname           77921   0.0  0.0  2433828   1972 s000  R+   11:17AM   0:00.00 grep puma
myname           67661   0.0  2.3  2680504 191204 s002  S+   11:00AM   0:18.38 puma 3.11.2 (tcp://localhost:3000) [my_proj]

then:

kill -9 67661

Found the script below in this github issue. Works great for me.

#!/usr/bin/env ruby
port = ARGV.first || 3000
system("sudo echo kill-server-on #{port}")

pid = `sudo lsof -iTCP -sTCP:LISTEN -n -P | grep #{port} | awk '{ print $2 }' | head -n 1`.strip
puts "PID: #{pid}"
`kill -9 #{pid}` unless pid.empty?

You can either run it in irb or inside a ruby file.

For the latter, create server_killer.rb then run it with ruby server_killer.rb

SOLUTION FOR GENERAL Address already in use - bind(2) (Errno::EADDRINUSE)

This issue is because we are trying to use the same port which is already is use. so we have to stop the services running on that port so that we can run another services. we can use kill like kill -9 {PID}where {PID} is the PID of the services running on that port. To know the PID of any services lets say "firefox" we can use commands like pidof firefox, ps aux | grep -i firefox ,pgrep firefox and then use the kill command to stop that service.

sometime we might get into the situation where we don't know the PID or the service name to search for in this case we can use the following little ruby code to do it for us.(in this case port 3000, you can change it according to your need)

#!/usr/bin/env ruby
port = ARGV.first || 3000
system("sudo echo kill-server-on #{port}")

pid = `sudo lsof -iTCP -sTCP:LISTEN -n -P | grep #{port} | awk '{ print $2 }' | head -n 1`.strip
puts "PID: #{pid}"
`kill -9 #{pid}` unless pid.empty?

save it as something.rb and run sudo ruby something.rb