升级jenkins之后无法启动 报错Unable to read /var/lib/jenkins/config.xml

故障记录

点击jenkins升级后再点击回滚到之前版本，jenkins就起不来了。

欲哭无泪，报错如下

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:248)
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:47)
at jenkins.model.Jenkins.executeReactor(Jenkins.java:1075)
at jenkins.model.Jenkins.<init>(Jenkins.java:915)
at hudson.model.Hudson.<init>(Hudson.java:85)
at hudson.model.Hudson.<init>(Hudson.java:81)
at hudson.WebAppMain$3.run(WebAppMain.java:231)
Caused by: java.io.IOException: Unable to read /var/lib/jenkins/config.xml
at hudson.XmlFile.unmarshal(XmlFile.java:160)
at jenkins.model.Jenkins.loadConfig(Jenkins.java:2977)
at jenkins.model.Jenkins.access$1100(Jenkins.java:325)
at jenkins.model.Jenkins$16.run(Jenkins.java:2995)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:1051)
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:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.thoughtworks.xstream.io.StreamException:  : only 1.0 is supported as <?xml version not '1.1' (position: START_DOCUMENT seen <?xml version=\'1.1\'... @1:19)
at com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:124)
at com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:148)
at com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:141)
at com.thoughtworks.xstream.io.xml.AbstractPullReader.move(AbstractPullReader.java:118)
at com.thoughtworks.xstream.io.xml.AbstractPullReader.moveDown(AbstractPullReader.java:103)
at com.thoughtworks.xstream.io.xml.XppReader.<init>(XppReader.java:63)
at com.thoughtworks.xstream.io.xml.AbstractXppDriver.createReader(AbstractXppDriver.java:54)
at com.thoughtworks.xstream.io.xml.AbstractXppDriver.createReader(AbstractXppDriver.java:65)
at hudson.XmlFile.unmarshal(XmlFile.java:158)
... 11 more
Caused by: org.xmlpull.v1.XmlPullParserException: only 1.0 is supported as <?xml version not '1.1' (position: START_DOCUMENT seen <?xml version=\'1.1\'... @1:19)
at org.xmlpull.mxp1.MXParser.parseXmlDeclWithVersion(MXParser.java:2608)
at org.xmlpull.mxp1.MXParser.parseXmlDecl(MXParser.java:2592)
at org.xmlpull.mxp1.MXParser.parsePI(MXParser.java:2466)
at org.xmlpull.mxp1.MXParser.parseProlog(MXParser.java:1447)
at org.xmlpull.mxp1.MXParser.nextImpl(MXParser.java:1395)
at org.xmlpull.mxp1.MXParser.next(MXParser.java:1093)
at com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:109)
... 19 more

　　

幸好之前用ThinBackup插件做了每日备份。

问题原因：升级jenkins之后配置文件格式变化，导致降配后的jenkins无法读取配置文件

解决方法：

1，cd  /var/lib/jenkins/  #进入到jenkins的程序目录

mv config.xml config.xmlbak  #重命名

2，cd /backupjenkins #切换到ThinBackup的备份目录

cd FULL-2018-02-05_00-00 #切换到每日备份目录

cp config.xml /var/lib/jenkins/  #还原配置文件

3，service jenkins restart #重启jenkins

4，大功告成，jenkins又可以恢复使用啦~跑了几个构建也ok。

教训：

不要随意升级jenkins，升级操作请谨慎，升级之前请对程序目录进行备份；养成备份的好习惯，别等到宕机才欲哭无泪

ps:其实重命名config.xml后重启jenkins已经可以重启成功了，但是相关的用户配置和安全策略都没有了，jenkins处于没有保护的状态，所以最好是使用之前的配置文件进行还原。