一段时间没登录jenkins，可能把密码忘记了，再登录时总是提示：登录信息无效。请重试。If you are a system administrator and suspect this to be a configuration problem, see the server console output for more details.应该是密码或者账号不对了。怎么找回密码呢，只能去配置文件中修改了
首先找到jenkins的目录：-DJENKINS_HOME=/var/lib/jenkins
此目录下会有一个users文件夹(jenkins/users/admin)，存放着各登录用户的账号信息，一个用户账户一个文件夹。文件夹里有配置文件：config.xml，内容如下：
<?xml version=‘1.0‘ encoding=‘UTF-8‘?> <user> <fullName>admin</fullName> <description>总管理员账号</description> <properties> <jenkins.security.ApiTokenProperty> <apiToken>rWArknUk9PnLS7riVJGISU/HFkjErmpNNNuiDC31aFd0SjdAh0ih3tN8GDkC94Nm</apiToken> </jenkins.security.ApiTokenProperty> <jenkins.security.LastGrantedAuthoritiesProperty> <roles> <string>authenticated</string> </roles> <timestamp>1475071638132</timestamp> </jenkins.security.LastGrantedAuthoritiesProperty> <hudson.model.MyViewsProperty> <primaryViewName></primaryViewName> <views> <hudson.model.AllView> <owner class="hudson.model.MyViewsProperty" reference="../../.."/> <name>All</name> <filterExecutors>false</filterExecutors> <filterQueue>false</filterQueue> <properties class="hudson.model.View$PropertyList"/> </hudson.model.AllView> </views> </hudson.model.MyViewsProperty> <hudson.model.PaneStatusProperties> <collapsed/> </hudson.model.PaneStatusProperties> <hudson.security.HudsonPrivateSecurityRealm_-Details> <passwordHash>#jbcrypt:$2a$10$NqPv3NpgxkpQi/ffEsEkhuMZYpbKc5cVVrP60cD6MX5IujYkLlOGm</passwordHash> </hudson.security.HudsonPrivateSecurityRealm_-Details> <org.jenkinsci.main.modules.cli.auth.ssh.UserPropertyImpl> <authorizedKeys></authorizedKeys> </org.jenkinsci.main.modules.cli.auth.ssh.UserPropertyImpl> <hudson.search.UserSearchProperty> <insensitiveSearch>false</insensitiveSearch> </hudson.search.UserSearchProperty> </properties> </user>
如上面的配置文件，把passwordHash改成上面的值（对应密码是123456）,账户就是这个文件夹的名称，改好后登录jenkins，在管理平台上修改密码即可。
原文：https://www.cnblogs.com/wsy0202/p/13154487.html