MySQL connection issue on a container

katkol · March 7, 2018, 12:52pm

Hi,

I want a docker container with ubuntu base image and mysql and java installed on top of it in order to run a hibernate based java application within it. Here is the dockerfile, I created.

FROM ubuntu
RUN echo "mysql-server-5.7 mysql-server/root_password password root" | debconf-set-selections
RUN echo "mysql-server-5.7 mysql-server/root_password_again password root" | debconf-set-selections
RUN apt-get update && apt-get install -yq mysql-server-5.7 && \
  rm -rf /var/lib/apt/lists/*
RUN apt-get update && apt-get install -y openjdk-8-jre-headless
ENV MYSQL_ROOT_PASSWORD=root
EXPOSE 3306 5684
WORKDIR /
ADD Server_Docker/target/Server-0.0.1-SNAPSHOT-jar-with-dependencies.jar server.jar
ADD Server_Docker/resources resources
ADD Server_Docker/policydb.sql policydb.sql
ADD mysql_start.sh mysql_start.sh
RUN "/bin/bash" "-c" "/etc/init.d/mysql restart"
RUN "/bin/bash" "-c" "sleep 5"
#RUN /bin/bash "-c" "mysql -uroot -proot -hlocalhost < policydb.sql"
CMD "java" "-jar" "server.jar"

but it raises a connection exception as shown below

docker run ws_app
Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Exception in thread "main" org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:244)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:208)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
	at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
	at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
	at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
	at org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:692)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
	at com.WSServer.WeatherStation_NGAC_Server.ngac_database.DatabaseManager.<init>(DatabaseManager.java:36)
	at com.WSServer.WeatherStation_NGAC_Server.Declarations.add_nodeTypes(Declarations.java:45)
	at com.WSServer.WeatherStation_NGAC_Server.Server.createNodes(Server.java:76)
	at com.WSServer.WeatherStation_NGAC_Server.Server.main(Server.java:47)
Caused by: org.hibernate.exception.JDBCConnectionException: Error calling Driver#connect
	at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:115)
	at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:101)
	at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:123)
	at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:41)
	at org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
	at org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:106)
	at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:40)
	at org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:19)
	at org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:138)
	at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:110)
	at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:74)
	at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:217)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:189)
	at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145)
	at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66)
	at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
	at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88)
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:234)
	... 17 more
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:590)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:57)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:1606)
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:633)
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:347)
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:219)
	at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38)
	... 32 more
Caused by: com.mysql.cj.core.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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:54)
	at com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:93)
	at com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:133)
	at com.mysql.cj.core.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:149)
	at com.mysql.cj.mysqla.io.MysqlaSocketConnection.connect(MysqlaSocketConnection.java:83)
	at com.mysql.cj.mysqla.MysqlaSession.connect(MysqlaSession.java:122)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:1726)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:1596)
	... 36 more
Caused by: java.net.UnknownHostException: mysql_server: Name or service not known
	at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)
	at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
	at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
	at java.net.InetAddress.getAllByName0(InetAddress.java:1276)
	at java.net.InetAddress.getAllByName(InetAddress.java:1192)
	at java.net.InetAddress.getAllByName(InetAddress.java:1126)
	at com.mysql.cj.core.io.StandardSocketFactory.connect(StandardSocketFactory.java:179)
	at com.mysql.cj.mysqla.io.MysqlaSocketConnection.connect(MysqlaSocketConnection.java:57)
	... 39 more

any suggestions on how to fix it?

Another issue is that,
when i uncomment the line RUN /bin/bash “-c” “mysql -uroot -proot -hlocalhost < policydb.sql” in dockerfile, I get build issues

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
The command '/bin/sh -c /bin/bash "-c" "mysql -uroot -proot -hlocalhost < policydb.sql"' returned a non-zero code: 1

Any suggestions about this aswell?

dmaze · March 7, 2018, 2:10pm

You almost certainly want two separate containers. At the bottom of Samples overview | Docker Docs are some application+database combos, and while none of them are either MySQL or Java per se the general pattern of “write a Dockerfile for your application only, plus a Docker Compose YAML file that starts both the application and a database” is still near-universal.

As a general rule, running scripts in /etc/init.d or commands like service or initctl just doesn’t work in Docker. If you find yourself wanting to do this, you probably should be running this service in a separate container and using Docker’s native networking to connect the two.

(You’re getting database connection errors because the database isn’t started; the entire runtime environment gets torn down after each individual RUN command, so when you get to the next RUN command or the actual docker run step, the database that got started before is gone.)

katkol · March 7, 2018, 3:07pm

Thanks for your answer. I tried with docker compose and it worked.