LoveCTO阿里云安装了elasticsearch,防火墙允许9200、9300端口访问，elasticsearch.yml关键配置：
network.host: 0.0.0.0
network.publish_host: 阿里云公网IP
elasticsearch版本6.4.2，java elasticsearch客户端相关版本均为6.4.2，java程序启动后，出现NoNodeAvailableException如下：
NoNodeAvailableException[None of the configured nodes are available: [{#transport#-1}{mGhxiIRoS2i1Vi3NLAz4zw}{xxx.xxx.xxx.xxx}{xxx.xxx.xxx.xxx:9300}]]
at org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:349)
at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:247)
at org.elasticsearch.client.transport.TransportProxyClient.execute(TransportProxyClient.java:60)
at org.elasticsearch.client.transport.TransportClient.doExecute(TransportClient.java:381)
at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:407)
at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:396)
at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.execute(AbstractClient.java:1254)
at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.exists(AbstractClient.java:1276)
at cn.lovecto.api.es.EsUtil.indexExists(EsUtil.java:98)
at cn.lovecto.api.es.EsTest.test(EsTest.java:26)
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:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:73)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:83)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
解决办法，到阿里云es控制台设置安全组才能用java访问9200端口，这里也需要将9300增加到安全组，增加后就正常访问了。
可参考：
https://jingyan.baidu.com/article/fea4511a2e387cf7bb912532.html
