[root@localhost /]# systemctl status jenkins.service

● jenkins.service - LSB: Jenkins Automation Server

   Loaded: loaded (/etc/rc.d/init.d/jenkins; bad; vendor preset: disabled)

   Active: failed (Result: exit-code) since 六 2019-09-28 09:27:02 CST; 27min ago

     Docs: man:systemd-sysv-generator(8)

  Process: 30069 ExecStart=/etc/rc.d/init.d/jenkins start (code=exited, status=1/FAILURE)

9月 28 09:27:02 localhost.localdomain systemd[1]: Starting LSB: Jenkins Automation Server...

9月 28 09:27:02 localhost.localdomain runuser[30074]: pam_unix(runuser:session): session opened for user jenkins by (uid=0)

9月 28 09:27:02 localhost.localdomain jenkins[30069]: Starting Jenkins bash: /usr/bin/java: 没有那个文件或目录

9月 28 09:27:02 localhost.localdomain jenkins[30069]: [失败]

9月 28 09:27:02 localhost.localdomain systemd[1]: jenkins.service: control process exited, code=exited status=1

9月 28 09:27:02 localhost.localdomain systemd[1]: Failed to start LSB: Jenkins Automation Server.

9月 28 09:27:02 localhost.localdomain systemd[1]: Unit jenkins.service entered failed state.

9月 28 09:27:02 localhost.localdomain systemd[1]: jenkins.service failed.

[root@localhost /]# which java

/usr/local/iron/jdk1.8.0_191/bin/java

#JDK的安装路径和Jenkins 默认的JDK路径不一致

#建立软连接

ln -s /usr/local/iron/jdk1.8.0_191/jdk/bin/java /usr/bin/java

#如果多版本，可以使用下面的命令更新

[root@localhost /]# update-alternatives --install /usr/bin/java java /usr/local/iron/jdk1.8.0_191/bin/java 300

[root@localhost /]# update-alternatives --install /usr/bin/javac javac /usr/local/iron/jdk1.8.0_191/bin/javac 300

[root@localhost /]# update-alternatives --install /usr/bin/jar jar /usr/local/iron/jdk1.8.0_191/bin/jar 300

[root@localhost /]# update-alternatives --install /usr/bin/javah javah /usr/local/iron/jdk1.8.0_191/bin/javah 300

[root@localhost /]# update-alternatives --install /usr/bin/javap javap /usr/local/iron/jdk1.8.0_191/bin/javap 300

[root@localhost /]# update-alternatives --config java

[root@localhost /]# which java

/usr/bin/java

vi /etc/rc.d/init.d/jenkins

candidates="

/etc/alternatives/java

/usr/lib/jvm/java-1.8.0/bin/java

/usr/lib/jvm/jre-1.8.0/bin/java

/usr/lib/jvm/java-1.7.0/bin/java

/usr/lib/jvm/jre-1.7.0/bin/java

/usr/lib/jvm/java-11.0/bin/java

/usr/lib/jvm/jre-11.0/bin/java

/usr/lib/jvm/java-11-openjdk-amd64

/usr/bin/java

/usr/local/iron/jdk1.8.0_191/bin/java #把自己配置的目录加进去

"