[FIXED] Jenkins fails to start on centOS7

Issue

I am using jenkins on my centOS7/linux server. When I start jenkins and checked the status it showed me like this.

>jenkins.service - Jenkins Service  
>   Loaded: loaded (/etc/systemd/system/jenkins.service; enabled; vendor preset:  >  disabled)  
>   Active: failed (Result: exit-code) since Mon 2017-02-20 22:52:19 PST; 22s   > ago  
>  Process: 40251 ExecStart=/usr/bin/java -jar /usr/local/bin/jenkins.war    
>(code=exited, status=1/FAILURE)  
> Main PID: 40251 (code=exited, status=1/FAILURE)  
>Feb 20 22:52:19 CentOS7 systemd[1]: Started Jenkins Service.  
>Feb 20 22:52:19 CentOS7 systemd[1]: Starting Jenkins Service...  
>Feb 20 22:52:19 CentOS7 java[40251]: Error: Unable to access jarfile >/usr/l...ar  
>Feb 20 22:52:19 CentOS7 systemd[1]: jenkins.service: main process exited, >c...RE  
>Feb 20 22:52:19 CentOS7 systemd[1]: Unit jenkins.service entered failed state.  
>Feb 20 22:52:19 CentOS7 systemd[1]: jenkins.service failed.  
>Hint: Some lines were ellipsized, use -l to show in full.  

So I uninstalled the jenkins sudo yum remove jenkins by this command, and installed it again sudo yum install jenkins.
Now again facing the same issue.

Can anyone tell me what to do.

Thanks!!

Solution

Before you can install Jenkins, you need to setup a Java virtual machine on your system

yum install java-1.8.0-openjdk.x86_64

And set two environment variables: JAVA_HOME and JRE_HOME.

echo 'export JAVA_HOME=/usr/lib/jvm/jre-1.8.0-openjdk' | sudo tee -a /etc/profile
echo 'export JRE_HOME=/usr/lib/jvm/jre' | sudo tee -a /etc/profile
source /etc/profile

Then install jenkins and allow inbound traffic on port 8080.

You can see more details from how to install jenkins on Centos 7.

Hope this helps.

Answered By - McGrady
Answer Checked By - Marilyn (JavaFixing Volunteer)