Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm running into an intermittent error with my Ruby app and I'm trying to figure out the context. I'm running mod_passenger off of Apache (on Dreamhost, if that matters).

The error I'm getting is:

[ pid=12404 file=ext/apache2/Hooks.cpp:727 time=2012-04-30 02:59:02.949 ]:
  Unexpected error in mod_passenger: Could not send data to the ApplicationPool server: write() failed: Bad file descriptor (9)
     in 'virtual boost::shared_ptr<Passenger::Application::Session> Passenger::ApplicationPoolServer::Client::get(const Passenger::PoolOptions&)' (ApplicationPoolServer.h:402)
     in 'int Hooks::handleRequest(request_rec*)' (Hooks.cpp:523)

(That's how I know I'm running mod_passenger.) I tried to do a gem list | grep passenger, but that didn't turn up anything. I can see the module in /dh/apache2/template/lib/modules, I just don't know how to figure out what the version is.

share|improve this question
Which OS? How did you install passenger? – Michael Slade Apr 30 '12 at 11:49
up vote 2 down vote accepted

Take a look at your Apache error logs after starting up Apache. There should be a line like the following:

[Sun Apr 29 06:57:07 2012] [notice] Apache/2.2.14 (Ubuntu) Phusion_Passenger/3.0.11 mod_ssl/2.2.14 OpenSSL/0.9.8k configured -- resuming normal operations

What it says exactly depends on your Apache installation but it should tell you at least which Passenger version you have running. In my case it is 3.0.11, as you can see.

share|improve this answer
Perfect. For anyone on DH out there; it looks like the default deployment for a VPS uses 2.29: [Sat Apr 28 00:58:05 2012] [notice] Apache/2.2.17 (Unix) mod_ssl/2.2.17 OpenSSL/0.9.8o mod_fastcgi/2.4.6 mod_fcgid/2.3.4 Phusion_Passenger/2.2.9 configured -- resuming normal operations – Avery Chan Apr 30 '12 at 22:15

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.