Springboot error I/O error on post request for“ http://10.10.195.199:9411/api/v2/spans “: connect timed out; nested exception is java.net.SocketTimeoutException: connect timed out

Problem background solution experience Lyric: a sack of love and happiness

Problem background

When using Zipkin, the following error occurs when accessing the URL

2022-01-11 11:22:35.554  WARN [service-one,,,] 40592 --- [ender@131ff6fa}] z.r.AsyncReporter$BoundedAsyncReporter   : Spans were dropped due to exceptions. All subsequent errors will be logged at FINE level.
2022-01-11 11:22:35.557  WARN [service-one,,,] 40592 --- [ender@131ff6fa}] z.r.AsyncReporter$BoundedAsyncReporter   : Dropped 1 spans due to ResourceAccessException(I/O error on POST request for "http://10.10.195.199:9411/api/v2/spans": connect timed out; nested exception is java.net.SocketTimeoutException: connect timed out)

org.springframework.web.client.ResourceAccessException: I/O error on POST request for "http://10.10.195.199:9411/api/v2/spans": connect timed out; nested exception is java.net.SocketTimeoutException: connect timed out
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:751) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.cloud.sleuth.zipkin2.sender.ZipkinRestTemplateWrapper.doExecute(ZipkinRestTemplateSenderConfiguration.java:228) ~[spring-cloud-sleuth-zipkin-2.2.0.RELEASE.jar:2.2.0.RELEASE]
	at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:644) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.cloud.sleuth.zipkin2.sender.RestTemplateSender.post(RestTemplateSender.java:129) ~[spring-cloud-sleuth-zipkin-2.2.0.RELEASE.jar:2.2.0.RELEASE]
	at org.springframework.cloud.sleuth.zipkin2.sender.RestTemplateSender$HttpPostCall.doExecute(RestTemplateSender.java:142) ~[spring-cloud-sleuth-zipkin-2.2.0.RELEASE.jar:2.2.0.RELEASE]
	at org.springframework.cloud.sleuth.zipkin2.sender.RestTemplateSender$HttpPostCall.doExecute(RestTemplateSender.java:132) ~[spring-cloud-sleuth-zipkin-2.2.0.RELEASE.jar:2.2.0.RELEASE]
	at zipkin2.Call$Base.execute(Call.java:380) ~[zipkin-2.19.0.jar:na]
	at zipkin2.reporter.AsyncReporter$BoundedAsyncReporter.flush(AsyncReporter.java:285) ~[zipkin-reporter-2.11.0.jar:na]
	at zipkin2.reporter.AsyncReporter$Flusher.run(AsyncReporter.java:354) [zipkin-reporter-2.11.0.jar:na]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_172]
Caused by: java.net.SocketTimeoutException: connect timed out
	at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_172]
	at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) ~[na:1.8.0_172]
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_172]
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_172]
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_172]
	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_172]
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_172]
	at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_172]
	at sun.net.NetworkClient.doConnect(NetworkClient.java:175) ~[na:1.8.0_172]
	at sun.net.www.http.HttpClient.openServer(HttpClient.java:463) ~[na:1.8.0_172]
	at sun.net.www.http.HttpClient.openServer(HttpClient.java:558) ~[na:1.8.0_172]
	at sun.net.www.http.HttpClient.<init>(HttpClient.java:242) ~[na:1.8.0_172]
	at sun.net.www.http.HttpClient.New(HttpClient.java:339) ~[na:1.8.0_172]
	at sun.net.www.http.HttpClient.New(HttpClient.java:357) ~[na:1.8.0_172]
	at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1220) ~[na:1.8.0_172]
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1156) ~[na:1.8.0_172]
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1050) ~[na:1.8.0_172]
	at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:984) ~[na:1.8.0_172]
	at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:76) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:53) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:742) ~[spring-web-5.2.1.RELEASE.jar:5.2.1.RELEASE]
	... 9 common frames omitted

Solution

1. The firewall is not turned off

systemctl stop firewalld

Experience

1. I was tired of finding the problem. Another time, I just introduced Zipkin dependency, which was not used, and a similar error occurred.