Caused by: java.net.NoRouteToHostException: Host is unreachable

환경

docker, spring boot, mysql 로 구동되는 application 에서 

어제만 해도 잘 동작하던 application 이 코드 수정 후 업데이트를 하자 아래와 같은 에러를 냈다.

- 에러 내역

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836)
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456)
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246)
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198)
	at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138)
	at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358)
	at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206)
	at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477)
	at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560)
	at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115)
	at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112)
	at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122)
	at org.hibernate.internal.NonContextualJdbcConnectionAccess.obtainConnection(NonContextualJdbcConnectionAccess.java:38)
	at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:108)
	... 50 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
	at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
	at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89)
	at com.mysql.cj.NativeSession.connect(NativeSession.java:144)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:956)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826)
	... 63 common frames omitted
Caused by: java.net.NoRouteToHostException: Host is unreachable
	at java.base/sun.nio.ch.Net.pollConnect(Native Method)
	at java.base/sun.nio.ch.Net.pollConnectNow(Net.java:579)
	at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(NioSocketImpl.java:549)
	at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:597)
	at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:339)
	at java.base/java.net.Socket.connect(Socket.java:585)
	at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155)
	at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
	... 66 common frames omitted

찾아보니 네트워크 router 관련 문제라고 하였다.

 

확인

해당 서버에서 db 서버로 접속이 잘 되는지 command 접속하여 확인해봤더니 접속이 잘 되었다.

application 을 docker 없이 따로 구동시켰더니 잘 되었다.

따라서 docker 문제임을 알 수 있었는데, 따로 변경해주었던 사항은 없었어서

 

해결

image 를 삭제했다가 새로 말아서 하니 network를 잘 잡았는지 잘 되었다.

 

* 기타로 효과를 못봤던 작업은

docker 껐다 켜기 효과 없음

컴퓨터를 껐다 켜기 효과 없음