nacos在启动时报错Unable to start embedded Tomcat
org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:156)
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:744)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204)
at com.alibaba.nacos.Nacos.main(Nacos.java:35)
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:49)
at org.springframework.boot.loader.Launcher.launch(Launcher.java:108)
at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
at org.springframework.boot.loader.PropertiesLauncher.main(PropertiesLauncher.java:467)
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:124)
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.(TomcatWebServer.java:86)
at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:416)
at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:180)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180)
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153)
... 16 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'distroFilterRegistration' defined in class path resource [com/alibaba/nacos/naming/web/NamingConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.web.servlet.FilterRegistrationBean]: Factory method 'distroFilterRegistration' threw exception; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'distroFilter': Unsatisfied dependency expressed through field 'distroMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'distroMapper' defined in URL [jar:file:/D:/Program%20Files/nacos-server-2.0.3/nacos/target/nacos-server.jar!/BOOT-INF/lib/nacos-naming-2.0.3.jar!/com/alibaba/nacos/naming/core/DistroMapper.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'serverMemberManager' defined in URL [jar:file:/D:/Program%20Files/nacos-server-2.0.3/nacos/target/nacos-server.jar!/BOOT-INF/lib/nacos-core-2.0.3.jar!/com/alibaba/nacos/core/cluster/ServerMemberManager.class]: Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.alibaba.nacos.core.cluster.ServerMemberManager]: Constructor threw exception; nested exception is ErrCode:500, ErrMsg:jmenv.tbsite.net
问题原因：单机版开启了cluster模式
解决方案2种：
1. 修改startup.cmd（Windows系统） 或者 startup.sh（Linux）文件
修改如下：
Windows：搜索mode, 找到set MODE="cluster" 修改为 set MODE="standalone"
Linux：搜索mode, 找到export MODE="cluster" 修改为 export MODE="standalone"
2. 启动时主动写入启动模式 ./startup.cmd -m standalone
修改后启动正常：
