My container running a Spring boot version 2.4.0 app had been running for about 6 days, then it enters the situation when my-sql name not resolved by kubernetes cluster. But after I restarted this container, it just works fine with the my-sql resolved. So it is apparently not a DNS server issue. The problem is reproducible and it just happens about every 6 days. I saw the problem was reported with previous releases. My version is much newer than the fixed release. Could you please let me know what else information that I should collect to help to locate the root cause of this issue?
Caused by: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:99)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:111)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:138)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:273)
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:281)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:246)
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:83)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:164)
at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:421)
... 37 common frames omitted
Caused by: java.sql.SQLTransientConnectionException: HikariPool-1 - Connection is not available, request timed out after 30000ms.
at com.zaxxer.hikari.pool.HikariPool.createTimeoutException(HikariPool.java:695)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:197)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:162)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:128)
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)
... 44 common frames omitted
Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: 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 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.access$100(HikariPool.java:71)
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:725)
at com.zaxxer.hikari.pool.HikariPool$PoolEntryCreator.call(HikariPool.java:711)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
... 3 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at jdk.internal.reflect.GeneratedConstructorAccessor172.newInstance(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89)
at com.mysql.cj.NativeSession.connect(NativeSession.java:144)
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:956)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826)
... 14 common frames omitted
Caused by: java.net.UnknownHostException: som-mysql: Temporary failure in name resolution
at java.base/java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:930)
at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1499)
at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:849)
at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1489)
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1348)
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1282)
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:132)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
... 17 common frames omitted
Comment From: wilkinsona
Spring Boot 2.4 is no longer supported. Furthermore, communication between MySQL's JDBC driver and a MySQL server is out of Spring Boot's control.
But after I restarted this container, it just works fine with the my-sql resolved. So it is apparently not a DNS server issue.
It looks like a DNS issue to me. The exception message says that the failure is temporary:
java.net.UnknownHostException: som-mysql: Temporary failure in name resolution
It's then perhaps not surprising that the problem does not go on indefinitely.
Could you please let me know what else information that I should collect to help to locate the root cause of this issue?
I would start your investigation with DNS in your deployment environment as all the evidence that you've shared so far suggests that it's an intermittent DNS problem.
Comment From: jamesjodan
@wilkinsona Hi Wilkinsona,
Thank you very much for the response.
May I ask whether the libraries, org.springframework.data.jpa.repository.Query, org.springframework.data.repository.PagingAndSortingRepository, org.springframework.stereotype.Repository etc. will still be provided by recent Spring boot releases?
Comment From: scottfrederick
@jamesjodan The classes you mention are in Spring Data and Spring Framework, not in Spring Boot. Spring Boot manages the versions of those libraries but they are separate projects.