jhipster RDS connection issue - jhipster

Question

I'm trying to deploy to AWS an application developed with JHipster, but I get an error when trying to do so. It looks like I'm unable to connect to the database.
I created a simple JSP page that connects directly to the database via jdbc and it works fine, so it seems I'm doing something wrong when configuring the application.
This is my current application.yml:
spring:
profiles:
active: prod
datasource:
dataSourceClassName: com.mysql.jdbc.jdbc2.optional.MysqlDataSource
url: jdbc:mysql://rds_url:3306/db?user=user&password=password
databaseName: db
serverName: rds_url
username: user
password: password
cachePrepStmts: true
prepStmtCacheSize: 250
prepStmtCacheSqlLimit: 2048
useServerPrepStmts: true
And this is what I see in the logs:
Caused by: com.zaxxer.hikari.pool.PoolInitializationException: Exception during pool initialization
at com.zaxxer.hikari.pool.BaseHikariPool.initializeConnections(BaseHikariPool.java:542)
at com.zaxxer.hikari.pool.BaseHikariPool.<init>(BaseHikariPool.java:171)
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:60)
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:48)
at com.zaxxer.hikari.HikariDataSource.<init>(HikariDataSource.java:80)
at com.test.config.DatabaseConfiguration.dataSource(DatabaseConfiguration.java:83)
at com.test.config.DatabaseConfiguration$$EnhancerBySpringCGLIB$$b2394f0e.CGLIB$dataSource$1(<generated>)
at com.test.config.DatabaseConfiguration$$EnhancerBySpringCGLIB$$b2394f0e$$FastClassBySpringCGLIB$$e28d8821.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:309)
at com.test.config.DatabaseConfiguration$$EnhancerBySpringCGLIB$$b2394f0e.dataSource(<generated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:162)
... 137 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.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 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:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:389)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1038)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:338)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2237)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2270)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2069)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
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:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:389)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
at com.mysql.jdbc.jdbc2.optional.MysqlDataSource.getConnection(MysqlDataSource.java:422)
at com.mysql.jdbc.jdbc2.optional.MysqlDataSource.getConnection(MysqlDataSource.java:134)
at com.mysql.jdbc.jdbc2.optional.MysqlDataSource.getConnection(MysqlDataSource.java:105)
at com.zaxxer.hikari.pool.BaseHikariPool.addConnection(BaseHikariPool.java:438)
at com.zaxxer.hikari.pool.BaseHikariPool.initializeConnections(BaseHikariPool.java:540)
... 152 more
Caused by: java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:213)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:297)
... 169 more
Here's a link to more detailed logs.
Any help will be deeply appreciated.
Thanks,
Jodevan.

Answer 1

Alright. I made it work.
In order to test if there was some problem in the yml configuration file, I decided hard-coding the database properties directly in the DatabaseConfiguration.java file and it simply worked!
When the home page was rendered, my surprise: development mode!
I have no idea how this happened, since the package was supposed to be generated with the production profile activated. This is how the package was being generated as described here:
mvn -Pprod package
But I forgot that I also need to set this environment property in Tomcat.
By the way, since this is an Tomcat environment property, it's needed to restart your EBS environment.
Last but not least, make sure your RDS has a security group that allows connection from the EC2 where your EBS is configured.