Thin web server: `start_tcp_server': no acceptor (RuntimeError) after git branch checkout

Question

A Rails 3.2.0 app, working fine with Thin web server, both locally and on Heroku cedar stack.

After:

$ git branch work
$ git checkout work
$ rails server

I get:

=> Booting Thin
=> Rails 3.2.0 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
>> Thin web server (v1.3.1 codename Triple Espresso)
>> Maximum connections set to 1024
>> Listening on 0.0.0.0:3000, CTRL+C to stop
Exiting
/Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:572:in `start_tcp_server': no acceptor (RuntimeError)
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:572:in `start_server'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/backends/tcp_server.rb:16:in `connect'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/backends/base.rb:53:in `block in start'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `call'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run_machine'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/backends/base.rb:61:in `start'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/thin-1.3.1/lib/thin/server.rb:159:in `start'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/handler/thin.rb:13:in `run'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/rack-1.4.1/lib/rack/server.rb:265:in `start'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/railties-3.2.0/lib/rails/commands/server.rb:70:in `start'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/railties-3.2.0/lib/rails/commands.rb:55:in `block in <top (required)>'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/railties-3.2.0/lib/rails/commands.rb:50:in `tap'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/gems/railties-3.2.0/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'

Also, when I do:

sudo bundle exec rails server thin -p 3000

I get:

/Users/peter/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:247:in `to_specs': Could not find bundler (>= 0) amongst [bigdecimal-1.1.0, io-console-0.3, json-1.5.4, minitest-2.5.1, rake-0.9.2.2, rdoc-3.9.4] (Gem::LoadError)
from /Users/peter/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/site_ruby/1.9.1/rubygems/dependency.rb:256:in `to_spec'
from /Users/peter/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/site_ruby/1.9.1/rubygems.rb:1210:in `gem'
from /Users/peter/.rvm/gems/ruby-1.9.3-p125/bin/bundle:18:in `<main>'

I have bundler 1.0.22 installed. Updated and installed it. Nothing seems to work. Any ideas?

Do you already have a server running elsewhere on the machine? Perhaps in Cucumber or something? — Josh Leitzel, Mar 09 '12 at 18:17
No, I haven't. Actually, restarting my computer had solved my problem. Today it happened again. Seems to happen when I switch over from one git branch to another. — maeseele, Mar 21 '12 at 09:29
Thanks! My error message on MacOSX was `... eventmachine-1.0.0/lib/eventmachine.rb:526:in \`start_tcp_server': no acceptor (port is in use or requires root privileges) (RuntimeError)`. — JJD, Feb 03 '13 at 22:47
Same for me when I tried to use the same port to run two different application. This topic just made me think about the other running application. — Vadorequest, Feb 10 '14 at 12:34

score 226 · Answer 1 · answered Aug 15 '12 at 17:09

226

This works for me. Find (zombie?) server (can happen when quitting terminal with server running):

$ ps ax | grep rails

If it returns something like:

33467 s002 S+ 0:00.00 grep rails
33240 s003 S+ 0:15.05 /Users/Arta/.rbenv/versions/1.9.2-p290/bin/ruby script/rails s -p 3000

kill it, and run anew:

$ kill -9 33240
$ rails s

answered Aug 15 '12 at 17:09

Arta

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17

If `ps ax | grep rails` doesn't turn up anything, try `ps ax | grep ruby`. – Kevin May 20 '14 at 20:06
3

Definitely happens on OSX if you straight quit the terminal window while the rails server is running. +1 – notaceo Oct 15 '14 at 14:19

score 63 · Answer 2 · answered Mar 23 '12 at 14:41

63

The port 3000 may already be in use. Look at http://mrjaba.posterous.com/starttcpserver-no-acceptor-runtimeerror

answered Mar 23 '12 at 14:41

TuteC

4,342
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2

From the above-linked article, a command to locate rails servers already running (works on mac): `ps aux | grep rails` – Luke Griffiths Aug 16 '12 at 14:40

score 48 · Answer 3 · answered Feb 10 '14 at 10:05

48

If there's any other process locking the port, you can find out which PID it has like this:

$ lsof -i :3000
COMMAND     PID USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
Passenger 40466 josh    5u  IPv4 0x7cae9332073ed4df      0t0  TCP *:hbci (LISTEN)
Passenger 40467 josh    5u  IPv4 0x7cae9332073ed4df      0t0  TCP *:hbci (LISTEN)

Then simply kill it/them:

$ kill -9 40466
$ kill -9 40467

answered Feb 10 '14 at 10:05

Joshua Muheim

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`ntop` was using port 3000 on my machine. Answer is spot on. – Tass Jul 18 '14 at 17:41

Alborz · Answer 4 · 2012-10-19T13:22:44.203

47

pgrep ruby to see what servers are running and then

kill -9 serverNumber

;)

edited Oct 19 '12 at 13:22

answered Aug 02 '12 at 13:14

Alborz

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score 8 · Answer 5 · answered Jun 13 '12 at 15:58

8

rvmsudo rails server thin -p 3000

Does it for me

answered Jun 13 '12 at 15:58

wantrapreneur

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ExiRe · Answer 6 · 2014-07-21T08:37:01.923

6

I has this error because i was running rails-dev-box with Rails inside of it.

Port 3000 in the host computer is forwarded to port 3000 in the virtual machine. 
Thus, applications running in the virtual machine can be accessed via 
localhost:3000 in the host computer.

So is logged out from Vagrant and shutted down it:

vagrant@rails-dev-box:/vagrant/rails$ exit
$ vagrant halt

That helped me.

edited Jul 21 '14 at 08:37

answered Feb 10 '14 at 08:13

ExiRe

4,727
7
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I had the same problem. I had vagrant running from a separate project. Probably not common, but it helped me. Thanks! +1 – jake Jul 18 '14 at 17:36

score 5 · Answer 7 · answered May 16 '14 at 22:03

5

I had this error because I was already running rails in another terminal. Closing my other project fixed this.

answered May 16 '14 at 22:03

aarona

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If you want to run both programs at once, you can start your second server on a different port. – Kevin May 20 '14 at 20:07
@Kevin great point. That wasn't was I trying to do, has just forgot that the other project was running. – aarona May 21 '14 at 00:18
@DJ That makes sense. I was posting my comment for future readers :) – Kevin May 21 '14 at 00:37

score 2 · Answer 8 · answered Dec 02 '13 at 14:09

2

I ran into a similar issue after getting back to the office from vacation. I run my server on the local IP as:

rails s thin -b <my_ip>

The problem was that my IP had changed, I just needed to use the new one.

answered Dec 02 '13 at 14:09

pepe

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score 2 · Answer 9 · answered Sep 30 '14 at 10:31

2

Execute this in the terminal

sudo netstat -lpn |grep rails

And then

sudo kill <job id>

answered Sep 30 '14 at 10:31

Sam

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This was the only way I was able to find my processes, though I had to grep for thin instead of rails. – skillet-thief Aug 17 '15 at 22:23
Yes it works most of the cases. If you liked vote up please. – Sam Aug 26 '15 at 16:01
Finding and killing the process id did the trick. Though the first command didn't worked for me but `ps aux | grep rails`. – Francisco Quintero Jan 31 '16 at 21:12

Thin web server: `start_tcp_server': no acceptor (RuntimeError) after git branch checkout

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