Error using Passenger with RVM: "Passenger RequestHandler warning: someone tried to connect with an invalid connect password"

Question

As we (finally) port our apps away from Ruby 1.8.7, I am trying to set up Phusion Passenger and Apache, with RVM, to serve apps using both Ruby 1.87/Rails 2.3.x and Ruby 1.9.3/Rails 3.2.x. This is all on my development machine; in production we us separate VMs to serve the two different platforms--but needless to say, that would be inconvenient in development.

The Good: I've got Passenger 3.0.7 installed using Ruby 1.8.7 (and RVM), and 1.8.7/Rails 2.3.x apps work great as they have in the past (the only thing changed from my past setup is having (re)installed Passenger via RVM).

The Bad: I also have installed Passenger 4.0.20 as a gem using Ruby 1.9.3 (and RVM), and if I configure Apache to use them, it is able to serve up a 1.9.3/Rails 3.2.x app just fine. But Passenger can't serve the Ruby 1.8.7/Rails 2.3.x app.

Another developer here has essentially the same setup working but we are unable to see any clear differences between her installation and mine. But her success tells me it is possible.

The Ugly: When I try to run the 1.8.7/2.3.x app with Passenger 4.0.20, Passenger logs a bunch of output to the Apache error.log, including these lines:

[ 2013-10-22 13:12:30.1770 21240/7fe89ad0e700 Pool2/SmartSpawner.h:301 ]: Preloader for /home/username/workspace/app started on PID 21284, listening on unix:/tmp/passenger.1.0.21232/generation-0/backends/preloader.21284
[ 2013-10-22 13:12:30.2547 21240/7fe89ac8c700 Pool2/Implementation.cpp:1274 ]: [App 21284 stderr] [ 2013-10-22 13:12:30.2547 21385/0x7f9bf1fd0b80(Worker 1) request_handler/thread_handler.rb:197 ]: *** Passenger RequestHandler warning: someone tried to connect with an invalid connect password.

It's the last bit (scroll to the right!) that seems the most bizarre.

Some online searching reveals that Passenger supports some sort of 'connect password' but we are using no such thing. There are few Passenger-related references to 'someone tried to connect with an invalid connect password' outside of the Passenger source code.

I actually have solved this problem, but due to the dearth of references on the web, and my failure to find any mention of the 'invalid connect password' error here on SO, I am posting this to help the next person. I haven't included lots of other log snippets, configuration file contents and the like, because I have already mentioned all the relevant information.

If you think you know the answer, here's your chance to get some more 'reputation'. Otherwise, I'll post my answer in a couple days.

Answer 1

I found my answer in a passing remark on the Passenger forum.

Quoting my question, here is the real problem: "I also have installed Passenger 4.0.20 as a gem using Ruby 1.9.3 (and RVM)..."

I was able to solve it by re-installing Passenger 4.0.20 as a gem using Ruby 1.8.7 (and RVM). With this configuration, Passenger is able to serve up both Ruby 1.8.7 and Ruby 1.9.3 applications.

I have read that in addition to its mainly-native code, Passenger uses a bit of Ruby internally, interpreted by whatever version of Ruby it was installed with. Apparently (and wonderfully) this Ruby code is compatible with Rubies as ancient as 1.8.7. Equally wonderful, it will serve up applications with whatever Ruby their PassengerRuby directives specify... but apparently this isn't the case if Passenger is installed using a newer Ruby than the one needed by the application.

Big thanks to the Passenger and RVM teams, and also to Maximilian Herold for solving my mystery.

Answer 2

Phusion Passenger author here. The connect password is a security mechanism in Phusion Passenger to prevent unauthorized processes on the local system to connect to the spawned application processes. The connect password is only known to the HelperAgent, the app process and admin tools like passenger-status.

I'm not sure what went wrong in your case. I'd like to analyze your problem more deeply. Could set PassengerLogLevel to 3, trigger the problem, and post the contents of your Apache error log file to the community discussion forum?