title: Jenkins fails when running "service start jenkins"
body: <p>I installed jenkins on Centos 7 using the following:</p>
  <pre><code>sudo wget -O /etc/yum.repos.d/jenkins.repo http://pkg.jenkins.io/redhat-stable/jenkins.repo
  sudo rpm --import http://pkg.jenkins.io/redhat-stable/jenkins.io.key
  yum install jenkins
  </code></pre>
  <p>as <a href="http://pkg.jenkins-ci.org/redhat-stable/" rel="noreferrer">described on the official documentation</a></p>
  <p>However when I run:</p>
  <pre><code>service start jenkins
  </code></pre>
  <p>I get the following error message:</p>
  <pre><code>Starting jenkins (via systemctl):  Job for jenkins.service failed because the control process exited with error code. See &quot;systemctl status jenkins.service&quot; and &quot;journalctl -xe&quot; for details.
                                                             [FAILED]
  </code></pre>
  <p>Running <code>systemctl status jenkins.service</code> gives me this:</p>
  <pre><code>● jenkins.service - LSB: Jenkins Continuous Integration Server
     Loaded: loaded (/etc/rc.d/init.d/jenkins)
     Active: failed (Result: exit-code) since Wed 2016-09-21 16:45:28 BST; 3min 59s ago
       Docs: man:systemd-sysv-generator(8)
    Process: 2818 ExecStart=/etc/rc.d/init.d/jenkins start (code=exited, status=1/FAILURE)
  
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.JavaVMArguments.of(JavaVMArguments...04)
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.JavaVMArguments.current(JavaVMArgu...92)
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.Daemon.daemonize(Daemon.java:106)
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.Daemon.all(Daemon.java:88)
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: ... 6 more
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: jenkins.service: control process exited, code=exited s...s=1
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: Failed to start LSB: Jenkins Continuous Integration Server.
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: Unit jenkins.service entered failed state.
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: jenkins.service failed.
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: [FAILED]
  Hint: Some lines were ellipsized, use -l to show in full.
  </code></pre>
  <p>and running <code>journalctl -xe</code> gives me this:</p>
  <pre><code>Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.JavaVMArguments.of(JavaVMArguments.java:
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.JavaVMArguments.current(JavaVMArguments.
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.Daemon.daemonize(Daemon.java:106)
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: at com.sun.akuma.Daemon.all(Daemon.java:88)
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: ... 6 more
  Sep 21 16:45:28 webstack.local.caplib runuser[2819]: pam_unix(runuser:session): session closed for user jenkin
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: jenkins.service: control process exited, code=exited status=
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: Failed to start LSB: Jenkins Continuous Integration Server.
  -- Subject: Unit jenkins.service has failed
  -- Defined-By: systemd
  -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
  --
  -- Unit jenkins.service has failed.
  --
  -- The result is failed.
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: Unit jenkins.service entered failed state.
  Sep 21 16:45:28 webstack.local.caplib systemd[1]: jenkins.service failed.
  Sep 21 16:45:28 webstack.local.caplib jenkins[2818]: [FAILED]
  Sep 21 16:45:28 webstack.local.caplib polkitd[1392]: Unregistered Authentication Agent for unix-process:2813:8
  Sep 21 16:45:28 webstack.local.caplib dhclient[1390]: DHCPREQUEST on eno16777984 to 192.168.15.254 port 67 (xi
  Sep 21 16:45:28 webstack.local.caplib dhclient[1390]: DHCPACK from 192.168.15.254 (xid=0x2ab6e6bc)
  Sep 21 16:45:30 webstack.local.caplib dhclient[1390]: bound to 192.168.15.120 -- renewal in 865 seconds.
  Sep 21 16:45:36 webstack.local.caplib systemd[1]: Starting Cleanup of Temporary Directories...
  -- Subject: Unit systemd-tmpfiles-clean.service has begun start-up
  -- Defined-By: systemd
  -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
  --
  -- Unit systemd-tmpfiles-clean.service has begun starting up.
  Sep 21 16:45:36 webstack.local.caplib systemd[1]: Started Cleanup of Temporary Directories.
  -- Subject: Unit systemd-tmpfiles-clean.service has finished start-up
  -- Defined-By: systemd
  -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
  --
  -- Unit systemd-tmpfiles-clean.service has finished starting up.
  --
  -- The start-up result is done.
  </code></pre>
  <p>Both of which is really unhelpful. How do I fix this issue?</p>