服务器停机重启后jenkins启动失败，解决办法

前几天服务器突然停机重启了，重启后发现jenkins服务停了，去启动的时候启动不了

原因：服务器停机重启后，配置的jenkins文件的jdk目录失效了，恢复成了一开始的jdk目录

解决办法：重新去/etc/init.d下的jenkins文件中配置jdk再次启动即可。

错误信息: 6085 ExecStart=/usr/bin/jenkins (code=exited, status=1/FAILURE)

[root@localhost ~]# sudo systemctl start jenkins
Job for jenkins.service failed because the control process exited with error code. See "systemctl status jenkins.service" and "journalctl -xe" for details.
[root@localhost ~]# systemctl status jenkins.service
● jenkins.service - Jenkins Continuous Integration Server
   Loaded: loaded (/usr/lib/systemd/system/jenkins.service; enabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since 一 2023-10-30 09:25:16 CST; 17s ago
  Process: 6085 ExecStart=/usr/bin/jenkins (code=exited, status=1/FAILURE)
 Main PID: 6085 (code=exited, status=1/FAILURE)
10月 30 09:25:16 localhost.localdomain systemd[1]: jenkins.service: main process exited, code=exited, status=1/FAILURE
10月 30 09:25:16 localhost.localdomain systemd[1]: Failed to start Jenkins Continuous Integration Server.
10月 30 09:25:16 localhost.localdomain systemd[1]: Unit jenkins.service entered failed state.
10月 30 09:25:16 localhost.localdomain systemd[1]: jenkins.service failed.
10月 30 09:25:16 localhost.localdomain systemd[1]: jenkins.service holdoff time over, scheduling restart.
10月 30 09:25:16 localhost.localdomain systemd[1]: Stopped Jenkins Continuous Integration Server.
10月 30 09:25:16 localhost.localdomain systemd[1]: start request repeated too quickly for jenkins.service
10月 30 09:25:16 localhost.localdomain systemd[1]: Failed to start Jenkins Continuous Integration Server.
10月 30 09:25:16 localhost.localdomain systemd[1]: Unit jenkins.service entered failed state.
10月 30 09:25:16 localhost.localdomain systemd[1]: jenkins.service failed.

# 尝试启动命令
systemctl start jenkins
# 没启动起来，失败了，

 解决办法   一

1、请确保服务器上有jdk

可以输入命令，查看jdk安装目录

#linux命令
which java

2、直接在配置文件配置/etc/init.d下的jenkins文件中增加现有jdk的路径：记得systemctl daemon-reload一下

vi /etc/init.d/jenkins

然后尝试启动命令

cd /etc/init.d
# 启动
./jenkins start
# 停止
./jenkins stop
# 状态
./jenkins status

访问jenkins端口号，启动成功。