The main resource set specified [/tmp/tomcat-docbase.xx] is not valid.A child container failed 报错原因

一、启动项目时，报错：

2021-06-04 15:32:00.962 [main] INFO  org.apache.catalina.core.StandardService - Starting service [Tomcat]
2021-06-04 15:32:00.963 [main] INFO  org.apache.catalina.core.StandardEngine - Starting Servlet engine: [Apache Tomcat/9.0.34]
2021-06-04 15:32:01.002 [main] ERROR org.apache.catalina.core.ContainerBase - A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.webresources.StandardRoot@2438dcd]
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:192)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:916)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:841)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1384)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1374)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
	at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:909)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:421)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:930)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.startup.Tomcat.start(Tomcat.java:468)
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:106)
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:87)
	at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:437)
	at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:191)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
	at cn.gitv.op.points.OpPointsManagerApplication.main(OpPointsManagerApplication.java:14)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:51)
	at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:52)
Caused by: java.lang.IllegalArgumentException: The main resource set specified [/tmp/tomcat-docbase.8357879999865498877.10011] is not valid
	at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:752)
	at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:709)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	... 46 common frames omitted
Caused by: java.lang.IllegalArgumentException: The main resource set specified [/tmp/tomcat-docbase.8357879999865498877.10011] is not valid
	at org.apache.catalina.webresources.StandardRoot.createMainResourceSet(StandardRoot.java:752)
	at org.apache.catalina.webresources.StandardRoot.startInternal(StandardRoot.java:709)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	... 46 common frames omitted
2021-06-04 15:32:01.007 [main] INFO  org.apache.coyote.http11.Http11NioProtocol - Pausing ProtocolHandler ["http-nio-10011"]
2021-06-04 15:32:01.007 [main] INFO  org.apache.catalina.core.StandardService - Stopping service [Tomcat]
2021-06-04 15:32:01.009 [main] INFO  org.apache.coyote.http11.Http11NioProtocol - Destroying ProtocolHandler ["http-nio-10011"]
2021-06-04 15:32:01.049 [main] ERROR org.springframework.boot.SpringApplication - Application run failed
org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat

摘出关键信息：
The main resource set specified [/tmp/tomcat-docbase.8357879999865498877.10011] is not valid.

二、磁盘满了，清理一下就行了。
使用 df命令（英文全拼：disk free），看下磁盘使用情况：（-h 人类可读）

 df  -h