听起来你的安装出错了
尝试安装

sudo apt-get install jenkins

以获得正确的安装并重试

您的软件包安装错误。
尝试重新安装程序包。首先卸载并清除它。

sudo apt-get purge jenkins

重新安装

sudo apt-get install jenkins

这对我很有效：

systemctl daemon-reload

之后，错误消息更改为

Job for jenkins.service failed because the control process exited with error code.
See "systemctl status jenkins.service" and "journalctl -xe" for details.

阅读日志告诉了我实际的问题：

# cat /var/log/jenkins.rc
Apr. 16, 2020 10:54:25 VORM. Main verifyJavaVersion
FATAL: Running with Java class version 56 which is not in the list of supported versions: [52, 55]. Run with the --enable-future-java flag to enable such behavior. See https://jenkins.io/redirect/java-support/
java.lang.UnsupportedClassVersionError: 56.0
    at Main.verifyJavaVersion(Main.java:174)
    at Main.main(Main.java:142)

Jenkins requires Java versions [8, 11] but you are running with Java 12 from /usr/lib64/jvm/java-12-openjdk-12
java.lang.UnsupportedClassVersionError: 56.0
    at Main.verifyJavaVersion(Main.java:174)
    at Main.main(Main.java:142)