ROR + A server is already running. Check .../tmp/pids/server.pid. Exiting - ruby-on-rails-3

Question

In my Rails Project, I am trying to run two different servers at different port. But it fails by giving this error at console.
C:\Rails>rails s
=> Booting Mongrel
=> Rails 3.1.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
A server is already running. Check C:/Rails/tmp/pids/server.pid.Exiting
Please check the updated answer.

Answer 1

After googling a lot, I just delete that file and restart the server. Then again system create that file, then again I delete that file. Now Server is running fine. And System generates another copy at the same place. But it is running well.
DELETE THAT FILE ....
If you want to run two servers then it may again create trouble. So
Both commands are checking the default PID file location (tmp/pids/server.pid), so you're seeing this error. Try running multiple servers like so:
Server 1: bundle exec rails s
Server 2: bundle exec rails s -p 3001 -P tmp/pids/server2.pid
Credit: https://stackoverflow.com/a/14446920/1376448
Thanks
UPDATE after Connor Leech comment about Forman Gem
Foreman can help manage multiple processes that your Rails app depends
upon when running in development. It also provides an export command
to move them into production.

Answer 2

You can use netstat to know which process is holding the rails webserver, then you can kill the pid and start it over again, assuming that for some weird reason the server is not responding or running in background and you don't find another way to restart it..
netstat -plntu | grep 3000
tcp 0 0 0.0.0.0:3000 0.0.0.0:* LISTEN 7656/ruby
The last column shows the PID and the process name, then you only need to do:
kill -9 7656
and rails s to get it working again...
Hope it's useful

Answer 3

I find myself coming back to this webpage a lot to find the lsof -wni tcp:3000 command so I've found this method to be easier.
If you get this message:
A server is already running. Check /Users/username/project/tmp/pids/server.pid.
Exiting
And if you're running on a unix system (mac or linux) you can run these commands:
$ cat /Users/username/project/tmp/pids/server.pid
# output
71030
# Kill the process
$ kill -9 71030
Then run your server again!

Answer 4

I deleted the file with cd'ing in to the tmp directory then removing the file
rm server.pid
Then I restarted the server and I got this error
Exiting/Users/josephmellin/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/socket.rb:206:in `bind': Address already in use - bind(2) for 0.0.0.0:3000 (Errno::EADDRINUSE)
Then I could use the following command to see which process is running.
sudo lsof -iTCP -sTCP:LISTEN -P | grep :3000
And after I entered my password, I got this resoponse
ruby 2786 josephmellin 12u IPv4 0xfeadd8ae849eaec9 0t0 TCP *:3000 (LISTEN)
And then killed the process with the following command
KILL -9 2786
And then restarted the server (you will have a different number than 2786 - I left it here for demo purposes)

Answer 5

Step 1: remove .pid
C:/Rails/tmp/pids/server.pid.Exiting
# IN linux/unix shell
$ rm -rf <path to file>
Sometime this doesn't solve the problem, then you have to kill the process running by localhost, for such cases, follow STEP 2
STEP 2: List the process for localhost and kill it
# For Linux/Unix shell
$ lsof -wni tcp:3000
# output
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
ruby 5946 rails 11u IPv4 79073 0t0 TCP *:3000 (LISTEN)
ruby 5946 rails 12u IPv4 103786 0t0 TCP 127.0.0.1:3000->127.0.0.1:53612 (ESTABLISHED)
# Kill the running process
$ kill -9 5946
run your server again
rails server

Answer 6

ps aux | grep rails
or
bundle exec rails s -p 3001 -P tmp/pids/server2.pid

Answer 7

Every instance of a RoR server creates a PID file. By default it is
#{Rails.root}/tmp/pids/server.pid
and if that file already exists it will refuse to start a new server.
To run more than one server of the same project on the same machine you should manually specify the PID file name for each instance of the server (I recommend simply appending a hyphen and the port number) using the -P option:
rails s -p 1234 -P tmp/pids/server-1234.pid
I'm told in some cases you may need to supply a full (rather than relative) path, but I don't know what those cases are.

Answer 8

You can see the PID for each proccess(the first column) :
ps vax | grep rails
// OR: ps auxw | grep rails
5236 pts/1 Sl+ 1:46 2 0.2 /usr/bin/ruby1.9.1 script/rails s -p 3001
5298 pts/2 Sl+ 0:12 2 0.7 /usr/bin/ruby1.9.1 script/rails s -p 3003
7356 pts/5 Sl+ 0:09 2 0.9 /usr/bin/ruby1.9.1 script/rails s -p 3002
7846 pts/3 Sl+ 0:19 2 1.7 /usr/bin/ruby1.9.1 script/rails s
Then kill the server:
kill -9 <pid>
To kill all running apps with "rails" in the name:
killall -9 rails

Answer 9

Use rails default commands, for example:
rake tmp:clear
Works for me, and really simple. ;)

Answer 10

single line command, that will take care of it.
kill -9 $(more C:/Rails/tmp/pids/server.pid)

Answer 11

I just had this problem, just deleted server.pid file and server works fine!

Answer 12

Remove that file: C:/Rails/tmp/pids/server.pid

Answer 13

A simpler way in which I found lesser commands . Go to the path which says a server is running in your folder structure . Search for the file. On the file itself shows a number which is the process id that is currently running. Lets say if the number is 'x', then simply type this command into your terminal
kill -9 x
However, note that this works in Ubuntu. Not sure, if it works in other OS as well.

Answer 14

Try to change the number in the pid file to another and save it.