I've install apache from apache2-mpm-prefork package on EC2 micro instance and compiled passenger from source code present at following link:
The ruby version is 1.9.2-p290.
When the app is deployed and 'bundle install' is performed, the apache2 fails to start, along with this,
2373 ? 00:00:00 PassengerWatchd 2376 ? 00:00:00 PassengerHelper <defunct> 2381 ? 00:00:00 PassengerLoggin <defunct>
These passenger processes are found defunct. After instance reboot from command line, the apache2 is not started at reboot, which starts in normal cases, and the defunct passenger processes are present. The abnormal behavior observed is, after killing those processes manually the passenger and apache2 starts in normal way.