卸载或升级jenkins插件导致jenkins启动失败

#今天已经是第二次出现这个问题了，先解决之，mark之，后续研究一下为什么会出现这个问题~#

当出现启动失败，抛出excption时，可以尝试进行如下操作：

将security禁用，具体操作步骤如下：

停止jenkins (最方便的方式就是直接stop容器.)
切换到 $JENKINS_HOME 目录，找到config.xml文件并打开 .
搜索 <useSecurity>true</useSecurity> 这个字段.将true改成false
去掉 authorizationStrategy 和 securityRealm 这两个字段
重启jenkins

jenkins重启后将处于无安全配置状态，任何人都拥有全部的操作权限。

如果上述操作仍未生效, 请尝试重命名或者删除 config.xml 文件.

具体问题日志如下：

Error

hudson.util.HudsonFailedToLoad: org.jvnet.hudson.reactor.ReactorException: java.io.IOException: Unable to read /var/lib/jenkins/config.xml
at hudson.WebAppMain$3.run(WebAppMain.java:237)
Caused by: org.jvnet.hudson.reactor.ReactorException: java.io.IOException: Unable to read /var/lib/jenkins/config.xml
at org.jvnet.hudson.reactor.Reactor.execute(Reactor.java:269)
at jenkins.InitReactorRunner.run(InitReactorRunner.java:44)
at jenkins.model.Jenkins.executeReactor(Jenkins.java:914)
at jenkins.model.Jenkins.<init>(Jenkins.java:813)
at hudson.model.Hudson.<init>(Hudson.java:83)
at hudson.model.Hudson.<init>(Hudson.java:79)
at hudson.WebAppMain$3.run(WebAppMain.java:225)
Caused by: java.io.IOException: Unable to read /var/lib/jenkins/config.xml
at hudson.XmlFile.unmarshal(XmlFile.java:165)
at jenkins.model.Jenkins$16.run(Jenkins.java:2642)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:903)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.thoughtworks.xstream.converters.ConversionException: hudson.security.ProjectMatrixAuthorizationStrategy : hudson.security.ProjectMatrixAuthorizationStrategy

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