I have a rails application that I am deploying on an aws ec2 instance, this is my first time using the Rubber Gem, for which I have followed this tutorial. After removing the default nginx configurations and after intial deployment (step 5 of the tutorial I have mentioned) when ever I try and access my app using the public IP or DNS I get a 403 Forbidden nginx screen. On inspecting the error log of nginx on the server this is what I found. I have been stuck on this issue for quite sometime now, any help would be greatly appreciated. Thanks.
tail -f /var/log/nginx/error.log
[ 2015-07-10 05:49:13.7236 13522/7fc24be3a780 age/Wat/Main.cpp:1264 ]: Starting PassengerAgent watchdog...
[ 2015-07-10 05:49:13.7526 13525/7f2f7f588780 age/Hel/Main.cpp:944 ]: Starting PassengerAgent server...
[ 2015-07-10 05:49:13.7529 13525/7f2f7f588780 age/Hel/Main.cpp:237 ]: PassengerAgent server running in multi-application mode.
[ 2015-07-10 05:49:13.7550 13525/7f2f7f588780 age/Hel/Main.cpp:698 ]: PassengerAgent server online, PID 13525
[ 2015-07-10 05:49:13.7851 13530/7f39b592e780 age/Log/Main.cpp:442 ]: Starting PassengerAgent logger...
[ 2015-07-10 05:49:13.7863 13530/7f39b592e780 age/Log/Main.cpp:323 ]: PassengerAgent logger online, PID 13530
[ 2015-07-10 05:49:13.7876 13525/7f2f7f588780 age/Hel/Main.cpp:857 ]: Watchdog seems to be killed; forcing shutdown of all subprocesses
[ 2015-07-10 05:49:13.7877 13525/7f2f79042700 age/Hel/Main.cpp:508 ]: Signal received. Gracefully shutting down... (send signal 2 more time(s) to force shutdown)
2015/07/10 05:49:13 [alert] 9729#0: Required key 'core_address' is missing (-1: Unknown error)
Passenger author here. This error occurs when the Passenger module compiled inside Nginx, does not match the actual Passenger version that is installed. In other words, your installation is broken.
I recommend that you start over completely, on a new and empty server, using the Passenger official walkthrough documentation.