Error: “Passenger could not be initialized because of this error: Unable to start the Phusion Passenger watchdog centos”
SELinux blocks passenger from running when set to enforcing.
setenforce 0 /sbin/service httpd restart grep httpd /var/log/audit/audit.log | audit2allow -M passenger semodule -i passenger.pp setenforce 1
See http://wiki.centos.org/HowTos/SELinux for more information on SELinux
You may want to clear the audit log and then restart apache before running audit2allow
http://www.thedumbterminal.co.uk/php/knowledgebase/article/131
/etc/init.d/syslog stop rm /var/log/audit/audit.log /var/log/messages /etc/init.d/syslog start