I am having issues connecting to an Amazon RDS instance from an EC2 server, can connect from EVERYWHERE else

Question

I know there are other similar questions on the site, but I haven't been able to find a solution.

I have an RDS instance set up. We run our site on an EC2 instance.

I know MySQL works on the EC2 instance, because our current MySQL database is run on a different non-RDS server, and everything works fine.

I can connect to the RDS instance through MySQL workbench (I've approved my public IP address to connect).

I can connect to the RDS instance via phpMyAdmin, which is installed on the EC2 server.

However, I cannot connect to the RDS instance using PHP/MySQLi.

DEFINE ('DB_USER', '**user**'); DEFINE ('DB_PASSWORD', '**pass**'); DEFINE ('DB_HOST', '*************.rds.amazonaws.com'); if($dbc = @mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD)){ //DB connected, do nothing } else { echo 'Connection error'; echo mysqli_error(); exit(); } 

I'm getting no error output, nothing. It just echoes "Connection error".

I have the EC2 instance and RDS sharing a security group (although I can only edit inbound rules, not outbound, is this weird?), and have the EC2's public elastic IP allowed on the RDS security settings.

I'm lost!

Answer 1

Try following:

<?php $link = mysql_connect('localhost', 'mysql_user', 'mysql_password'); if (!$link) { die('Could not connect: ' . mysql_error()); } echo 'Connected successfully'; mysql_close($link); ?> 

Replace localhost, mysql_user and mysql_password with your credentials.

OR

//conection: mysqli_connect("myhost","myuser","mypassw","mybd") or die("Error " . mysqli_error($link));