After adding the ff lines on httpd.conf
LoadModule passenger_module /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.13/ext/apache2/mod_passenger.so
PassengerRoot /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.13
PassengerRuby /usr/local/bin/ruby
Apache won’t start anymore
[root@localhost ~]# service httpd restart
Stopping httpd: [FAILED]
Starting httpd: [FAILED]
Got this from log
[Thu Jul 12 11:26:58 2012] [error] *** Passenger could not be initialized because of this error: Unable to start the Phusion Passenger watchdog (/usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.13/agents/PassengerWatchdog): Permission denied (13)
[Thu Jul 12 11:26:58 2012] [notice] Digest: generating secret for digest authentication ...
[Thu Jul 12 11:26:58 2012] [notice] Digest: done
[Thu Jul 12 11:27:13 2012] [notice] SELinux policy enabled; httpd running as context root:system_r:httpd_t:s0
[Thu Jul 12 11:27:13 2012] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 12 11:31:56 2012] [notice] SELinux policy enabled; httpd running as context root:system_r:httpd_t:s0
[Thu Jul 12 11:31:56 2012] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 12 11:38:22 2012] [notice] SELinux policy enabled; httpd running as context root:system_r:httpd_t:s0
[Thu Jul 12 11:38:22 2012] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
Check the file permission on /usr/local/lib/ruby/gems/1.9.1/gems/passenger-3.0.13/agents/PassengerWatchdog and make sure that your apache user has permission to run it.