[eureka-server connection 에러] Caused by: org.apache.hc.client5.http.HttpHostConnectException: Connect to http://eureka-server:port 번호 [eureka-server/~~] failed: Connection refused

⭐️ 문제 상황

docker를 통해 eureka-server를 띄우는 과정에서 발생한 에러

✔️ 에러 메세지

Caused by: org.apache.hc.client5.http.HttpHostConnectException: Connect to http://eureka-server:10000 [eureka-server/172.26.0.5] failed: Connection refused
	at java.base/sun.nio.ch.Net.pollConnect(Native Method)
	at java.base/sun.nio.ch.Net.pollConnectNow(Net.java:672)
	at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(NioSocketImpl.java:542)
	at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:597)
	at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
	at java.base/java.net.Socket.connect(Socket.java:633)
	at org.apache.hc.client5.http.socket.PlainConnectionSocketFactory.lambda$connectSocket$0(PlainConnectionSocketFactory.java:91)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:569)
	at org.apache.hc.client5.http.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:90)
	at org.apache.hc.client5.http.socket.ConnectionSocketFactory.connectSocket(ConnectionSocketFactory.java:123)
	at org.apache.hc.client5.http.impl.io.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:189)
	at org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:450)
	at org.apache.hc.client5.http.impl.classic.InternalExecRuntime.connectEndpoint(InternalExecRuntime.java:162)
	at org.apache.hc.client5.http.impl.classic.InternalExecRuntime.connectEndpoint(InternalExecRuntime.java:172)
	at org.apache.hc.client5.http.impl.classic.ConnectExec.execute(ConnectExec.java:142)
	at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51)
	at org.apache.hc.client5.http.impl.classic.ProtocolExec.execute(ProtocolExec.java:192)
	at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51)
	at org.apache.hc.client5.http.impl.classic.HttpRequestRetryExec.execute(HttpRequestRetryExec.java:113)
	at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51)
	at org.apache.hc.client5.http.impl.classic.ContentCompressionExec.execute(ContentCompressionExec.java:152)
	at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51)
	at org.apache.hc.client5.http.impl.classic.RedirectExec.execute(RedirectExec.java:116)
	at org.apache.hc.client5.http.impl.classic.ExecChainElement.execute(ExecChainElement.java:51)
	at org.apache.hc.client5.http.impl.classic.InternalHttpClient.doExecute(InternalHttpClient.java:170)
	at org.apache.hc.client5.http.impl.classic.CloseableHttpClient.execute(CloseableHttpClient.java:87)
	at org.apache.hc.client5.http.impl.classic.CloseableHttpClient.execute(CloseableHttpClient.java:55)
	at org.apache.hc.client5.http.classic.HttpClient.executeOpen(HttpClient.java:183)
	at org.springframework.http.client.HttpComponentsClientHttpRequest.executeInternal(HttpComponentsClientHttpRequest.java:99)
	at org.springframework.http.client.AbstractStreamingClientHttpRequest.executeInternal(AbstractStreamingClientHttpRequest.java:70)
	at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66)
	at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:112)
	at org.springframework.cloud.netflix.eureka.http.RestTemplateTransportClientFactory.lambda$restTemplate$3(RestTemplateTransportClientFactory.java:170)
	at org.springframework.http.client.InterceptingClientHttpRequest$InterceptingRequestExecution.execute(InterceptingClientHttpRequest.java:88)
	at org.springframework.http.client.InterceptingClientHttpRequest.executeInternal(InterceptingClientHttpRequest.java:72)
	at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48)
	at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66)
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:889)
	... 21 more

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⭐️ 해결 방안

✔️ 고군분투

• docker network inspect bridge 해당 명령어로 bridge 확인했을 때 다른 모듈들은 같이 up했음에도 불구하고, containers에 아무것도 연결되어있지 않았다.
  
• 10000 포트에 잘 연결되어 있는지
  # curl http://eureka-server:10000/eureka/apps
  해당 명령어로 확인했을 때,
  curl: (7) Failed to connect to eureka-server port 10000: Connection refused
  이렇게 떴다.

✔️ 결론

기존에는 이미 빌드되어 있는 eureka를 사용하기 위해 따로 이미지를 빌드하지 않았다.
혹시나 하는 마음에 eureka-server를 빌드한 후 run해보니 잘 돌아간다.......
원인이 무엇인가,,,,,,

추측하건대,,
포트번호를 10000:10000으로 설정했고, hostName을 eureka-server로 명시했다.
기본 eureka는 docker에서 8761을 쓰기 때문에 포트번호로 인해 에러가 발생했던 것이라 생각한다.
실제로 connection refused 에러가 발생했다.

때문에 명확하게 설정된 코드들을 바탕으로 따로 빌드했기 때문에 에러가 사라진 것인 것 같다.