This jenkins instance appears to be offline windows

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 Jenkins instance appears to be offline» and offers options to «Configure Proxy» or «Skip Plugin Installation»

The machine clearly isn’t offline as I just used the internet connection to do the installation.
I also had a previous installation, done exactly the same way, that was working.
I removed the previous installation as Pipelines wouldn’t work and Google told me it was because of JDK 9. So I removed all the JDK/JRE installations as well as jenkins, fresh installed JDK 8 only, installed Jenkins, and got to here.

Jenkins has worked on this box in the past so what makes it think it is offline?

Update: Found a log file /var/lib/jenkins/logs/tasks/Download metadata.log
and it starts with a message FATAL: Connection refused (Connection refused)
I would think that indicates that the internet connection is OK, but something else is stopping it getting data?

Update: Based on other research I checked the Update Site in the Plugin Manager. This is listed as http://updates.jenkins-ci.org/update-center.json and, from the command line a wget of this file succeeds. So most definitely not a connection issue. Worked with both http and https, jenkins works with neither.

asked Feb 23, 2017 at 6:38

For macOS users:

Step -1: Edit /Users/Shared/Jenkins/Home/hudson.model.UpdateCenter.xml and change url to use http instead of https.

Step -2: Restart jenkins (for instance by going to http:localhost:8080) and reload the website

Step -3(Optional): If it asks for user and password and if you don’t remember creating one; default user is admin and copy the password from

sudo cat /Users/Shared/Jenkins/Home/secrets/initialAdminPassword

credits — @Alex in this post and @Tuan Pham here and @Joe Walsh for the comment on macOS directory path

answered Dec 14, 2017 at 17:46

in my case (macOS), updating jdk to 8 and reinstall jenkins solved the problem.

I also faced this issue i.e. This Jenkins instance appears to be offline on windows 10.

Below are the steps I followed to solve it:

1. Navigate to the Jenkins Home Directory.
   For me, the default home directory is: C:WindowsSystem32configsystemprofileAppDataLocalJenkins.jenkins

2. Changed the protocol from HTTPS to HTTP in the file hudson.model.UpdateCenter.xml

3. Restarted Jenkins (Go to C:Program FilesJenkins and then execute jenkins.exe stop, jenkins.exe start)

4. Logged in to Jenkins again (http://localhost:8080/).

The offline error got solved.

in case you are running jenkins in a container and vi is not installed
access your container in interactive mode

docker exec -it jenkins-ci /bin/bash

use this sed command to replace https with http

sed -i 's/https/http/g' /var/jenkins_home/hudson.model.UpdateCenter.xml 

answered Sep 30, 2020 at 0:22

On MacOS 10.11.6 :

1. Go to /Users/<UserName>/.jenkins

2. Open the file hudson.model.UpdateCenter.xml

3. Change the value of default from https://xxx to http://xxx

1. Took note of the secret Administrator password path that Jenkins displays when first opening http://localhost:8080/ on a browser.

2. The path was: C:Users{username}AppDataLocalJenkins.jenkinssecrets.
   Therefore the hudson.model.UpdateCenter file was at C:Users{username}AppDataLocalJenkins.jenkins

3. Updated the hudson.model.UpdateCenter file in notepad to have text http instead of https as follows:
   http://updates.jenkins.io/update-center.json

4. Reloaded the http://localhost:8080/ page but still showed the text «This Jenkins instance appears to be offline.»

5. Then navigated to the Services App in Windows (click Windows and type ‘Services App’ and it should display the App in the search list)

6. In the services App right clicked the Jenkins service and selected Restart.

7. After Windows restarted the Jenkins service navigated to http://localhost:8080/
   The Jenkins page wouldn’t even load. Navigated to the Jenkins login page: http://localhost:8080/login?from=%2F

8. Then got a loading page with text:’Please wait while Jenkins is getting ready to work …
   Your browser will reload automatically when Jenkins is ready.’
   Assumed that Jenkins was still restarting.

9. Once the Jenkins login page loaded, entered that password/secret again and clicked Continue.

10. This time the page with «This Jenkins instance appears to be offline.» was not displayed. Jenkins displayed a Getting Started -> Customize Jenkins page with buttons to install plugins.

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

answered Nov 11, 2018 at 17:17

answered May 8, 2020 at 14:11

answered Feb 1, 2021 at 22:17

answered Mar 6, 2021 at 14:16

Another possibility — make sure DNS functions properly for Jenkins.

In my case, I followed Kubernetes setup instructions here to install Jenkins, and it led to this problem.

I enabled logging on CoreDNS and saw this:

│ [INFO] 10.70.116.14:45888 - 50490 "AAAA IN updates.jenkins.io.svc.cluster.local. udp 54 false 512" NXDOMAIN qr,aa,rd 147 0.0001896s                          │
│ [INFO] 10.70.116.14:45888 - 32566 "A IN updates.jenkins.io.svc.cluster.local. udp 54 false 512" NXDOMAIN qr,aa,rd 147 0.000169468s                           │
│ [INFO] 10.70.116.14:57907 - 22912 "A IN updates.jenkins.io.localdomain. udp 48 false 512" NOERROR qr,aa 110 0.000907476s                                     │
│ [INFO] 10.70.116.14:57907 - 52100 "AAAA IN updates.jenkins.io.localdomain. udp 48 false 512" NOERROR qr,aa 110 0.001709031s 

The lookups were all cluster-local.

If I edited the URL (as suggested in other answers here) to include a dot after updates.jenkins.io. then hostname lookup worked and the URL resolved. Though Jenkins’ next step errors for the same reason.

In the end I discovered the problem was ClusterFirst mode of the pod’s DNS. I added dnsPolicy: Default to the deployment’s pod template spec (the instructions link above), and now it works.

answered Apr 21, 2021 at 20:13

In my case, I use WINDOWS OS. So, jenkins was installed in my C drive.

PATH : C:UsersUsername .jenkins

Under «hudson.model.UpdateCenter» file change «https» to «http»

<?xml version='1.1' encoding='UTF-8'?>
<sites>
<site>
<id>default</id>
<url>http://updates.jenkins.io/update-center.json</url>
</site>
</sites>

answered Oct 8, 2021 at 15:14

As some others pointed out, in Windows, this could be because of firewall restrictions set by company infrastructure.
For my case, I need the recommended plugins to be present (e.g. Folders plugin)

My workaround was:

A. Install same Jenkins version into my personal laptop/VM, and be sure to install the recommended plugins the first time you browse to the Jenkins Web Page.

B. Copy the plugins folder from my personal laptop’s JENKINS HOME folder (i.e. ProgramDataJenkins…) into the Jenkins plugins folder of the company laptop.
Total size of the plugins folder was around 150MB (zipped).

Enter this before running Jenkins.

# iptalbes -F

It may be because of the firewall.

answered Jul 2, 2018 at 6:25