Jenkins failed to start in linux

Question

go to run jenkins after doing an upgrade, and get the following:

start jenkins start: Job failed to start 

That's it...nothing shows up in jenkin's log...so it is difficult to debug to say the least. (and it isn't running already, or anything like that).

Is there another log somewhere that I should be looking at that would be helpful? (I am assuming answer to this problem will be somewhat iterative, so hopefully someone can start me on a path to debug this)

Answer 1

So, knowing it was a pre-start error allowed me to investigate more deeply.

Further digging allowed me to figure out that the exact line in the /etc/init/jenkins.conf file was one pointing to the /usr/share/jenkins/bin/maintain-plugins.sh

Looking at this location, I found it was not present (ie. no bin directory). This means that jenkins-common was no longer installed for some reason...odd indeed...going into apt-get and doing an install of this component again led to the error:

dpkg error processing /var/cache/apt/archives/jenkins-common_1.409.1-0ubuntu4.2_all.deb ... 

having seen this error before and refreshing my memory via google gave the following solution:

dpkg -i --force-overwrite /var/cache/apt/archives/jenkins-common_1.409.1-0ubuntu4.2_all.deb 

This allowed the installation of common to proceed as normal. After this, all I had to do was replace the /usr/share/jenkins/jenkins.war with my backed up copy (because ubuntu is far behind the latest release version), and I was able to start the server again.

I am not exactly sure what caused the problem to begin with, but it was likely during an apt-get upgrade/clean process...and because of the weirdness with jenkins conflicting with jenkins-common, it did not repopulate the /usr/share/jenkins directory properly.

regardless, am glad it is working again. :)