jenkins忘记admin密码，重置密码：

1.找打jenkins目录下面的config.xml

[root@VM-0-15-centos .jenkins]# find ./* -name config.xml
./config.xml
[root@VM-0-15-centos .jenkins]# pwd 
/root/.jenkins

删除下面的这部分内容：
[root@VM-0-15-centos .jenkins]# vim config.xml
  
  <useSecurity>true</useSecurity>
  <authorizationStrategy class="hudson.security.FullControlOnceLoggedInAuthorizationStrategy">
    <denyAnonymousReadAccess>true</denyAnonymousReadAccess>
  </authorizationStrategy>
  <securityRealm class="hudson.security.HudsonPrivateSecurityRealm">
    <disableSignup>true</disableSignup>
    <enableCaptcha>false</enableCaptcha>
  </securityRealm>

2.然后再重启一下jenkins：

[root@VM-0-15-centos jenkins]# ps -ef |grep jenkins
root     2962002 2918204 77 15:57 pts/2    00:01:13 /data/jenkins/jdk-11.0.15.1/bin/java -jar jenkins.war --httpPort=8800
root     2965716 2918204  0 15:59 pts/2    00:00:00 grep --color=auto jenkins
[root@VM-0-15-centos jenkins]# kill -9 2962002
[root@VM-0-15-centos jenkins]# nohup /data/jenkins/jdk-11.0.15.1/bin/java -jar jenkins.war --httpPort=8800 > nohup.out &
[1] 2962558
[root@VM-0-15-centos jenkins]# nohup: ignoring input and redirecting stderr to stdout

 3.然后再访问页面：http://ip:8800

或者 点击系统管理找到全局安全配置（Configure Global Security）

4.找到管理用户重新设置密码