Why does Jenkins say “This Jenkins instance appears to be offline”

Question

I have a fresh install of Jenkins 2.32.2 on Ubuntu. Opened a browser on the instance and get to a page titled Offline, with the message \"This Jenki

Answer 1

I make no claims about this, especially Java related (I personally cannot stand the language), but on my Ubuntu 18.04 L/T, I needed to stand-up a standalone Jenkins instance; So I installed both the Java on which Jenkins appears to be dependent and Jenkins itself

sudo apt install openjdk-8-jdk jenkins

Then I updated the Jenkins defaults

sudo gvim /etc/default/jenkins

... inserting the following at the top of the file - only because editing /etc/init.d/jenkins appeared to serve no purpose as it had no effect whatsoever ...

JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/
PATH=$JAVA_HOME:$PATH

Finally, save & quit ... then attempt Jenkins restart

sudo service jenkins restart

HTH - it certainly worked for me :-)