How do I check what version of mod_passenger I'm running?

Question

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)
  Backtrace:
     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.

Answer 1

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.