Java web application cannot connect to AWS RDS DB Instance

Question

I created DB Instance (MySQL) with Publicly Accessible option. In DB Security group, I opened MySQL Port for EC2 instance security group(Web server). In EC2 security group it allows ssh, web server ports. I can able to connect DB Instance from EC2 instance. I deployed web app on web server and it can't able to connect with RDS Instance.

I am getting the exception in my local web server:

org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Server connection failure during transaction. Due to underlying exception: 'java.net.UnknownHostException: "kbawstry2.cdhtaamn5ynq.us-east-1.rds.amazonaws.com"'.

EC2 Security Group

DBInstance Security Group

Using MySQL WorkBench, I can connect to RDS DB Instance using TCP/IP SSH Tunnelling option. But in Java Programming How can I connect with database?

Thanks in advance.

can you also tell the outbound rule for your ec2 instance security group? — Amit
– Amit, Commented Jan 8, 2017 at 12:30
All traffic are opened in outbound both in EC2 Security group and DB Instance Security Group. — Kumaresh Babu N S
– Kumaresh Babu N S, Commented Jan 8, 2017 at 12:41
Really, I don't know. I installed and configure apache-tomcat 7 for deploying web apps. — Kumaresh Babu N S
– Kumaresh Babu N S, Commented Jan 8, 2017 at 13:09
@KumareshBabu Could you share the code, where DB connection code is written ? — Amit
– Amit, Commented Jan 8, 2017 at 15:25

Kumaresh Babu N S · Accepted Answer · 2017-01-17 12:13:40Z

1

Finally I solved the issue. The problem is in application the way I mentioned connection string. I rectified and tested application in localhost then updated to tomcat server in EC2 instance. Another change in DB Security Group. I replaced source ip as EC2 instance's private IP address as both RDS and EC2 Instance are in same VPC.

Now It is working fine.

answered Jan 17, 2017 at 12:13

Kumaresh Babu N S

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3 Comments

Amit Over a year ago

it would be better if you mention what did you change in the connection string as well.

Kumaresh Babu N S Over a year ago

In code, I was mentioned double quotes for connection string so it was getting failed to connect with RDS database. Next I rectified the problem made it works.

Shiv Over a year ago

I faced same error but in my case i haven't configured rule as well. I removed double quotes from property file, Its started working fine.

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