问题描述

近期在做一个数据抓取的服务（SpringBoot），底层采用阿里云Elasticsearch，当我在该服务中引入 elasticsearch-rest-high-level-client jar 包，启动 Application 的过程中，出现如下报错信息：

2021-04-15 09:25:36.157[WARN ]org.springframework.boot.actuate.elasticsearch.ElasticsearchRestHealthIndicator:   89-Elasticsearch health check failed
java.net.ConnectException: Connection refused
	at org.elasticsearch.client.RestClient$SyncResponseListener.get(RestClient.java:943)
	at org.elasticsearch.client.RestClient.performRequest(RestClient.java:227)
	at org.springframework.boot.actuate.elasticsearch.ElasticsearchRestHealthIndicator.doHealthCheck(ElasticsearchRestHealthIndicator.java:61)
	at org.springframework.boot.actuate.health.AbstractHealthIndicator.health(AbstractHealthIndicator.java:84)
	at org.springframework.boot.actuate.health.CompositeHealthIndicator.health(CompositeHealthIndicator.java:98)
	at org.springframework.boot.actuate.health.HealthEndpoint.health(HealthEndpoint.java:50)
	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.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:246)
	at org.springframework.boot.actuate.endpoint.invoke.reflect.ReflectiveOperationInvoker.invoke(ReflectiveOperationInvoker.java:76)
	at org.springframework.boot.actuate.endpoint.annotation.AbstractDiscoveredOperation.invoke(AbstractDiscoveredOperation.java:61)
	at org.springframework.boot.actuate.endpoint.jmx.EndpointMBean.invoke(EndpointMBean.java:126)
	at org.springframework.boot.actuate.endpoint.jmx.EndpointMBean.invoke(EndpointMBean.java:99)
	at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
	at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
	at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
	at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
	at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
	at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
	at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
	at sun.reflect.GeneratedMethodAccessor63.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
	at sun.rmi.transport.Transport$1.run(Transport.java:200)
	at sun.rmi.transport.Transport$1.run(Transport.java:197)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:835)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Connection refused
	at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
	at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
	at org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.processEvent(DefaultConnectingIOReactor.java:171)
	at org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor.processEvents(DefaultConnectingIOReactor.java:145)
	at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:351)
	at org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager.execute(PoolingNHttpClientConnectionManager.java:221)
	at org.apache.http.impl.nio.client.CloseableHttpAsyncClientBase$1.run(CloseableHttpAsyncClientBase.java:64)
	... 1 common frames omitted

问题分析

从上边的报错信息来分析，产生问题的原因应该是引入的 elasticsearch-rest-high-level-client 对 elasticsearch 服务自动进行了健康检查。由于当前的 SpringBoot 服务未对 elasticsearch 进行任何配置，据此判断 elasticsearch-rest-high-level-client 是根据默认配置对 elasticsearch 服务进行健康检查的。

问题解决

既然在 SpringBoot 中未对 elasticsearch 进行任何配置，依此我们可以得出 elasticsearch-rest-high-level-client 默认开启了健康检查。那么要解决报错的问题，无非就两种办法：

1. 老老实实的将 elasticsearch 需要的配置信息补全

   spring:
     elasticsearch:
       rest:
         uris: ["http://es-cn-z8w24oaso0skkko88.public.elasticsearch.aliyuncs.com:9200"]
         # 如果连接Elasticsearch服务需要认证的话，那么就需要提供 username、password
         username: es
         password: es2021aa
   

   注意这里的 username 和 password，很多 Blog 中都没有对这两个参数进行说明，因为阿里云 Elasticsearch 是需要认证才能访问的，所以要想访问的话必须提供 username 和 password。如果不提供，会报如下错误信息：

   2021-04-15 10:33:12.289[WARN ]org.springframework.boot.actuate.elasticsearch.ElasticsearchRestHealthIndicator:   89-Elasticsearch health check failed
   org.elasticsearch.client.ResponseException: method [GET], host [http://es-cn-z8w24oaso0skkko88.public.elasticsearch.aliyuncs.com:9200], URI [/_cluster/health/], status line [HTTP/1.1 401 Unauthorized]
   {"error":{"root_cause":[{"type":"security_exception","reason":"missing authentication token for REST request [/_cluster/health/]","header":{"WWW-Authenticate":"Basic realm=\"security\" charset=\"UTF-8\""}}],"type":"security_exception","reason":"missing authentication token for REST request [/_cluster/health/]","header":{"WWW-Authenticate":"Basic realm=\"security\" charset=\"UTF-8\""}},"status":401}
   	at org.elasticsearch.client.RestClient$SyncResponseListener.get(RestClient.java:920)
   	at org.elasticsearch.client.RestClient.performRequest(RestClient.java:227)
   	at org.springframework.boot.actuate.elasticsearch.ElasticsearchRestHealthIndicator.doHealthCheck(ElasticsearchRestHealthIndicator.java:61)
   	at org.springframework.boot.actuate.health.AbstractHealthIndicator.health(AbstractHealthIndicator.java:84)
   	at org.springframework.boot.actuate.health.CompositeHealthIndicator.health(CompositeHealthIndicator.java:98)
   	at org.springframework.boot.actuate.health.HealthEndpoint.health(HealthEndpoint.java:50)
   	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.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:246)
   	at org.springframework.boot.actuate.endpoint.invoke.reflect.ReflectiveOperationInvoker.invoke(ReflectiveOperationInvoker.java:76)
   	at org.springframework.boot.actuate.endpoint.annotation.AbstractDiscoveredOperation.invoke(AbstractDiscoveredOperation.java:61)
   	at org.springframework.boot.actuate.endpoint.jmx.EndpointMBean.invoke(EndpointMBean.java:126)
   	at org.springframework.boot.actuate.endpoint.jmx.EndpointMBean.invoke(EndpointMBean.java:99)
   	at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
   	at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
   	at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
   	at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
   	at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
   	at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
   	at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
   	at sun.reflect.GeneratedMethodAccessor63.invoke(Unknown Source)
   	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   	at java.lang.reflect.Method.invoke(Method.java:498)
   	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
   	at sun.rmi.transport.Transport$1.run(Transport.java:200)
   	at sun.rmi.transport.Transport$1.run(Transport.java:197)
   	at java.security.AccessController.doPrivileged(Native Method)
   	at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
   	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
   	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:835)
   	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
   	at java.security.AccessController.doPrivileged(Native Method)
   	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
   	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
   	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
   	at java.lang.Thread.run(Thread.java:748)
   

2. 简单粗暴的关闭健康检查
   在 application.yaml 文件中添加如下信息：

   management:
     health:
       elasticsearch:
         enabled: false # true:开启，false：关闭，默认为 true
   

题外话

在使用 elasticsearch-rest-high-level-client 的时候，尽量保证所依赖的 elasticsearch 相关 jar 包一个版本，不然可能出现各种奇奇怪怪的问题（例如：找不到类等等），例如：我使用的 elasticsearch-rest-high-level-client 版本是 6.4.3，其他依赖 jar 包如下：