Unable to bind to port 80, but running on the current shell works without any issues

Question

I get the following error while trying to run "cap production unicorn:start"

F, [2013-07-12T04:36:18.134045 #28998] FATAL -- : error adding listener addr=0.0.0.0:80
/home/ec2-user/apps/foo_prod/shared/bundle/ruby/2.0.0/gems/unicorn-4.6.3/lib/unicorn/socket_helper.rb:147:in `initialize': Permission denied - bind(2) (Errno::EACCES)

Running the following command manually, does work without any issues. What could be the problem here?

rvmsudo unicorn_rails -c config/unicorn/production.rb -D --env production

Answer 1

You need root access to bind to lower ports like port 80. Command rvmsudo executes in root context and therefore it works.

Cap task executes in a normal user context (probably deploy) depending on your configuration. You should add sudo ability to cap deploy user and make sure your cap task uses sudo to start unicorn.

Answer 2

Answer by @Iuri G. gives you reason and possible solution.

I have another suggestion, unless you have extremely compelling reason to run Unicorn with port 80, change that to a higher port (>1024), like 3000. This will solve your problem.

If it is an application that is exposed to public, it is too easy to overwhelm Unicorn and make your application unavailable to end users. In such a case, do put Unicorn behind a proxy (like Nginx). The proxy will be on port 80 and Unicorn on a higher port.

Answer 3

In my development environment, using RubyMine, I ran into this recently.

I used SSH to redirect port 80 to 8080.

sudo ssh -t -L 80:127.0.0.1:8080 [email protected]