【Zookeeper】zookeeper not connected

一、問題分析和代碼跟蹤

原來跑的好好的代碼，晚上運行的時候提示連接不上 zookeeper。提示信息如下：

java.lang.IllegalStateException: zookeeper not connected
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperClient.<init>(CuratorZookeeperClient.java:83) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperTransporter.createZookeeperClient(CuratorZookeeperTransporter.java:26) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.remoting.zookeeper.support.AbstractZookeeperTransporter.connect(AbstractZookeeperTransporter.java:70) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.remoting.zookeeper.ZookeeperTransporter$Adaptive.connect(ZookeeperTransporter$Adaptive.java) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.metadata.store.zookeeper.ZookeeperMetadataReport.<init>(ZookeeperMetadataReport.java:61) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.metadata.store.zookeeper.ZookeeperMetadataReportFactory.createMetadataReport(ZookeeperMetadataReportFactory.java:37) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.metadata.report.support.AbstractMetadataReportFactory.getMetadataReport(AbstractMetadataReportFactory.java:49) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.metadata.report.MetadataReportFactory$Adaptive.getMetadataReport(MetadataReportFactory$Adaptive.java) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.metadata.report.MetadataReportInstance.init(MetadataReportInstance.java:49) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.startMetadataReport(DubboBootstrap.java:630) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.initMetadataService(DubboBootstrap.java:716) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.initialize(DubboBootstrap.java:517) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.bootstrap.DubboBootstrap.start(DubboBootstrap.java:744) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.spring.context.DubboBootstrapApplicationListener.onContextRefreshedEvent(DubboBootstrapApplicationListener.java:59) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.spring.context.DubboBootstrapApplicationListener.onApplicationContextEvent(DubboBootstrapApplicationListener.java:52) ~[dubbo-2.7.7.jar:2.7.7]
	at org.apache.dubbo.config.spring.context.OneTimeExecutionApplicationContextEventListener.onApplicationEvent(OneTimeExecutionApplicationContextEventListener.java:40) ~[dubbo-2.7.7.jar:2.7.7]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:898) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) [spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) [spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) [spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
	at com.tom.bootdubboorderprovider.BootDubboOrderProviderApplication.main(BootDubboOrderProviderApplication.java:12) [classes/:na]
Caused by: java.lang.IllegalStateException: zookeeper not connected
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperClient.<init>(CuratorZookeeperClient.java:80) ~[dubbo-2.7.7.jar:2.7.7]
	... 30 common frames omitted

2020-06-29 23:20:58.928  INFO 5200 --- [           main] .b.c.e.AwaitingNonWebApplicationListener :  [Dubbo] Current Spring Boot Application is about to shutdown...
2020-06-29 23:20:58.935  INFO 5200 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2020-06-29 23:20:58.935  INFO 5200 --- [           main] f.a.ReferenceAnnotationBeanPostProcessor : class org.apache.dubbo.config.spring.beans.factory.annotation.ReferenceAnnotationBeanPostProcessor was destroying!

Process finished with exit code 1

點開報錯信息，跟蹤進源碼，發現異常的拋出是由於在等待連接返回時的返回值false

跟進方法，可以看到他在不斷循環等待連接成功，若在最大等待時間內連接上，則返回true，否則false

綜合所述，猜測是由於網絡原因，超時所致（畢竟窮逼買的是100多塊錢一年的服務器~~~）

 

二、繼續深入

猜出了大概原因，如果是超時所致，且使用 dubbo-admin 發現 Zookeeper 運行狀態正常，那麼只要提高最大等待時間就可以了

根據關鍵字發現，可能跟 metadata-report 的設置有關，且 timeout 有個默認值 5 秒

繼續跟蹤，查找 CuratorZookeeperClient 方法的調用

結果很明顯，這個 timeout 是從配置文件中讀取出來的，若沒有，則是 5000 ms

 

三、修改配置文件

# 設置最大等待時間爲10秒
dubbo.metadata-report.timeout=10000

 

四、重試 => 翻車

重試依舊報錯，查看

再去找配置文件

# 配置中心連接時間改爲10秒
dubbo.config-center.timeout=10000