After installing Jenkins, I start the service with systemctl start jenkins. systemctl takes a long time to return and systmctl status jenkins returns the service is running.

I am not able to access jenkins from the web browser. Firewall port is open

When jenkins is running 1 CPU is at 100% permanently.

jenkins log doesn't report anything after:

INFO: Beginning extraction from war file

I've tried with JRE version 1.7 and 1.8, and get the same behavior.

I also stopped jenkins service, downloaded the jenkins.war and executed it manually. Here are the traces I get.

# java -jar jenkins.war
Running from: /root/jenkins.war
webroot: $user.home/.jenkins
Oct 31, 2018 6:18:58 PM org.eclipse.jetty.util.log.Log initialized
INFO: Logging initialized @139124ms to org.eclipse.jetty.util.log.JavaUtilLog
Oct 31, 2018 6:19:00 PM winstone.Logger logInternal
INFO: Beginning extraction from war file

I tried also other ports than 8080, jenkins port + firewall config. All attempts have the same behavior.