I have read over and over again on the question: Jenkins Crashes after installing GitHub Plugin, but I did not find the solution. Therefore I want to ask again.
My Jenkins server was working just fine at the very first, and I wanted to add a hook which triggers a build whenever there is a commit pushed to my repo; then I referred to the first step - which is installing a plugin from this site: Triggering a Jenkins build from a push to GitHub, and right after I finished installing the plugin, I clicked the "restart" checkbox at the bottom of the page, then it crashed. I tried to restart my Jenkins service, it kept giving the same error. So I just killed the process using ps tools, then restarted again, now it gives an HTTP 503 error. I really need some help with this issue. Actually, I found very similar issues on Stack Overflow and the Jenkins online community, but none of them did resolve my question.
I tried as: deleting all the files in the jenkins/plugins folder and restart again, but NOT WORKING.
I deployed Jenkins on my Linux machine, which is SUSE Linux Enterprise. Please give some help which is appreciated.
You have the old Jenkins version and probably the way to fix the issue is the installing of a new Jenkins (last LTE release).
You can backup config.xml file of your job (see this answer) and then try upgrade or re-install the Jenkins.
Then if you need to import this job to the new re-installed Jenkins, you need to place it in $JENKINS_HOME/jobs/<path_to_your_job> directory and you have to click "Manage Jenkins" -> "Reload Configuration From Disk".
However, if some plugins in your job have the differences between releases, then it's possible that in new job you will not see that plugin configuration and you will need to configure it again. If you want to do upgrade, not re-install, then all jobs will be migrated automatically (you don't need to do "Reload Configuration From Disk"), but again some plugin configurations can be lost, that's why I recommend you to backup your job configs before upgrading.
Note: I prefer to not upgrade to the new version, but to do full re-installing (if you don't have a lot of system and plugins configuration in your old Jenkins).