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

Question

I am trying to deploy Rails app with the Puma web server. When trying to start Puma server with a config file bundle exec puma -C config/puma.rb I get an error that the address is already in use.
Does someone know how to fix this?
bundle exec puma -C config/puma.rb
[23699] Puma starting in cluster mode...
[23699] * Version 2.11.3 (ruby 2.0.0-p353), codename: Intrepid Squirrel
[23699] * Min threads: 5, max threads: 5
[23699] * Environment: development
[23699] * Process workers: 2
[23699] * Preloading application
Jdbc-MySQL is only for use with JRuby
[23699] * Listening on tcp://0.0.0.0:3000
/.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `initialize': Address already in use - bind(2) (Errno::EADDRINUSE)
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `new'
from /Users/lexi87/.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:210:in `add_tcp_listener'
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:96:in `block in parse'
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:82:in `each'
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/binder.rb:82:in `parse'
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/runner.rb:119:in `load_and_bind'
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/cluster.rb:302:in `run'
from /.rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/lib/puma/cli.rb:216:in `run'
from /rvm/gems/ruby-2.0.0-p353/gems/puma-2.11.3/bin/puma:10:in `<top (required)>'
from /.rvm/gems/ruby-2.0.0-p353/bin/puma:23:in `load'
from /.rvm/gems/ruby-2.0.0-p353/bin/puma:23:in `<main>'
from /.rvm/gems/ruby-2.0.0-p353/bin/ruby_executable_hooks:15:in `eval'
from /.rvm/gems/ruby-2.0.0-p353/bin/ruby_executable_hooks:15:in `<main>'

Answer 1

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

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

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

Answer 6

If the above solutions don't work on ubuntu/linux then you can try this
sudo fuser -k -n tcp port
Run it several times to kill processes on your port of choosing. port could be 3000 for example. You would have killed all the processes if you see no output after running the command

Answer 7

You can find and kill the running processes: ps aux | grep puma
Then you can kill it with kill PID

Answer 8

I had this issue on my Macbook Air, running Rails 5.0.3, Puma 5.2.2
Tried running
lsof -wni tcp:3000 but there's no process on this port number.
Managed to fix this by running:
export PORT=3000 on my terminal, then I just added this extra line to my .bash_profile

Answer 9

It might be old but in my case, it was because of docker. Hope it will help others.