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From: Tatsuya Ono <ononoma@gmail.com>
To: mongrel-unicorn <mongrel-unicorn@rubyforge.org>
Subject: Unicorn in the jail
Date: Wed, 3 Aug 2011 17:41:03 +0100	[thread overview]
Message-ID: <CAHBuKRj09FdxAgzsefJWotexw-7JYZGJMtgUp_dhjPz9VbKD6Q@mail.gmail.com> (raw)

I ran into a problem when sending USR2 signal to master process which
is listening a TCP port. It shows the following error in log.

err: adding listener failed addr= (in use)

I found similar error reported on this mailing list and yes, the host
I got the error was in the FreeBSD jail.

I dug into the problem and found some interesting thing. I want to
share it and the solution here.

* Why does it happen in the Jail?
When you bind address to the socket on a Jail host, Jail
doesn't bind Instead of it, it binds to the IP address of the
host such as,, etc.
Then the problem happens in Unicorn::HttpServer#inherit_listeners!
when it gets signal like USR2.

Here you get (for example) as inherited address from
ENV['UNICORN_FD'] but So Unicorn tries to bind to
(again) at line 728. Then it fails because it is actually in use.

* How to solve the issue?
Thankfully unicorn.conf is ruby script so that I could write a logic
for Jail hosts without specifying IP address of those hosts (which we
want to avoid since we deploy it multiple servers). I share the
configuration file.

Then Unicorn flies in the jail happily.

Tatsuya Ono
Unicorn mailing list - mongrel-unicorn@rubyforge.org
Do not quote signatures (like this one) or top post when replying

             reply	other threads:[~2011-08-03 16:48 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-03 16:41 Tatsuya Ono [this message]
2011-08-03 18:03 ` Unicorn in the jail Eric Wong
2011-08-03 21:57   ` Tatsuya Ono

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