Install Jenkins via RPM per instructions.
(There is nothing else running on the system, i.e. httpd, etc.)
Edit
/etc/sysconfig/jenkins
Change
JENKINS_PORT from JENKINS_PORT="8080" to JENKINS_PORT="80"
or any other setting (i.e. -1)
Restart jenkins using
service jenkins restart
Get
Starting Jenkins [ OK ]
check status
service jenkins status
Get
jenkins dead but pid file exists
No information in logs of what, when, or why.