On my Ubuntu 18 Bionic server, I installed Jenkins. Upon completion of the installation, there was error message that goes something like this:
Output from sudo journalctl -xe
Feb 19 14:10:17 macmini.shinstudio.lan jenkins[21270]: OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)
Feb 19 14:10:17 macmini.shinstudio.lan jenkins[21270]: Aborting
Feb 19 14:10:17 macmini.shinstudio.lan systemd[1]: jenkins.service: Control process exited, code=exited status=1
Feb 19 14:10:17 macmini.shinstudio.lan systemd[1]: jenkins.service: Failed with result 'exit-code'.
Feb 19 14:10:17 macmini.shinstudio.lan systemd[1]: Failed to start LSB: Start Jenkins at boot time.
-- Subject: Unit jenkins.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit jenkins.service has failed.
--
-- The result is RESULT.
Feb 19 14:10:18 macmini.shinstudio.lan systemd[1]: Reloading.
Feb 19 14:10:18 macmini.shinstudio.lan systemd[1]: Starting resolvconf-pull-resolved.service...
-- Subject: Unit resolvconf-pull-resolved.service has begun start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit resolvconf-pull-resolved.service has begun starting up.
Feb 19 14:10:18 macmini.shinstudio.lan systemd[1]: Started resolvconf-pull-resolved.service.
-- Subject: Unit resolvconf-pull-resolved.service has finished start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit resolvconf-pull-resolved.service has finished starting up.
--
-- The start-up result is RESULT.
Feb 19 14:10:22 macmini.shinstudio.lan sudo[19303]: pam_unix(sudo:session): session closed for user root
Feb 19 14:10:28 macmini.shinstudio.lan kernel: [UFW BLOCK] IN=enp0s10 OUT= MAC=01:00:5e:00:00:01:f0:9f:c2:c6:9e:f4:08:00 SRC=192.168.1.101 DST=224.0.0.1 LEN=32 TOS=0x00 PREC=0xC0 TTL=1 I
Feb 19 14:11:19 macmini.shinstudio.lan sudo[21416]: shane : TTY=pts/0 ; PWD=/var/log/jenkins ; USER=root ; COMMAND=/bin/systemctl start jenkins
Feb 19 14:11:19 macmini.shinstudio.lan sudo[21416]: pam_unix(sudo:session): session opened for user root by shane(uid=0)
Feb 19 14:11:19 macmini.shinstudio.lan systemd[1]: Starting LSB: Start Jenkins at boot time...
-- Subject: Unit jenkins.service has begun start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit jenkins.service has begun starting up.
Feb 19 14:11:19 macmini.shinstudio.lan jenkins[21419]: Found an incorrect Java version
Feb 19 14:11:19 macmini.shinstudio.lan jenkins[21419]: Java version found:
Feb 19 14:11:20 macmini.shinstudio.lan jenkins[21419]: openjdk version "10.0.2" 2018-07-17
Feb 19 14:11:20 macmini.shinstudio.lan jenkins[21419]: OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4)
Feb 19 14:11:20 macmini.shinstudio.lan jenkins[21419]: OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)
Feb 19 14:11:20 macmini.shinstudio.lan jenkins[21419]: Aborting
Feb 19 14:11:20 macmini.shinstudio.lan systemd[1]: jenkins.service: Control process exited, code=exited status=1
Feb 19 14:11:20 macmini.shinstudio.lan sudo[21416]: pam_unix(sudo:session): session closed for user root
Feb 19 14:11:20 macmini.shinstudio.lan systemd[1]: jenkins.service: Failed with result 'exit-code'.
Feb 19 14:11:20 macmini.shinstudio.lan systemd[1]: Failed to start LSB: Start Jenkins at boot time.
-- Subject: Unit jenkins.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit jenkins.service has failed.
--
-- The result is RESULT.
Feb 19 14:11:29 macmini.shinstudio.lan kernel: [UFW BLOCK] IN=enp0s10 OUT= MAC=01:00:5e:00:00:01:f0:9f:c2:c6:9e:f4:08:00 SRC=192.168.1.101 DST=224.0.0.1 LEN=32 TOS=0x00 PREC=0xC0 TTL=1 I
Feb 19 14:11:33 macmini.shinstudio.lan sudo[21467]: shane : TTY=pts/0 ; PWD=/var/log/jenkins ; USER=root ; COMMAND=/bin/journalctl -xe
Feb 19 14:11:33 macmini.shinstudio.lan sudo[21467]: pam_unix(sudo:session): session opened for user root by shane(uid=0)
The first thing I noticed was the Java version, which is 10.0.2+13-Ubuntu… In the past when I worked with Jenkins, JDK was mostly 8. So, I googled about JDK 10+ and Jenkins and found this link. I thought that the content was not convincing me much whether JDK 10+ would work well with Jenkins…
I decided to downgrade to JDK 8 and here’s what I did (did not actual uninstall JDK 10 and reinstall JDK 8)
sudo update-alternatives –config java
There are 2 choices for the alternative java (providing /usr/bin/java).
Selection Path Priority Status
————————————————————
* 0 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1101 auto mode
1 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1101 manual mode
2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode
Press
update-alternatives: using /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java to provide /usr/bin/java (java) in manual mode
[20] ? java -version
openjdk version “1.8.0_191”
OpenJDK Runtime Environment (build 1.8.0_191-8u191-b12-0ubuntu0.18.04.1-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)
After confirming java executable points to 1.8 instead of 10/11, I started Jenkins successfully.
[21] ? sudo systemctl start jenkins
[22] ? ps aux | grep jenkins
jenkins 21545 0.2 0.2 76632 7640 ? Ss 14:14 0:00 /lib/systemd/systemd --user
jenkins 21546 0.0 0.0 257560 2936 ? S 14:14 0:00 (sd-pam)
jenkins 21561 0.0 0.0 19096 188 ? S 14:14 0:00 /usr/bin/daemon --name=jenkins --inherit --env=JENKINS_HOME=/var/lib/jenkins --output=/var/log/jenkins/jenkins.log --pidfile=/var/run/jenkins/jenkins.pid -- /usr/bin/java -Djava.awt.headless=true -jar /usr/share/jenkins/jenkins.war --webroot=/var/cache/jenkins/war --httpPort=8080
jenkins 21562 100 3.0 2953332 114708 ? Sl 14:14 0:13 /usr/bin/java -Djava.awt.headless=true -jar /usr/share/jenkins/jenkins.war --webroot=/var/cache/jenkins/war --httpPort=8080
shane 21617 0.0 0.0 13136 1088 pts/0 S+ 14:14 0:00 grep --color=auto jenkins
No error and Jenkins is up and running!