How to access RDS instance which in private subnet from ec2 instance from another private subnet?

Question

I want to access RDS instance from ec2 instance. Both are in different private subnet but in same VPC.

John Rotenstein John Rotenstein · Accepted Answer · 2018-05-30T11:29:03

Resources within the same VPC (even in different subnets) can certainly access each other.

Check your security groups. The best configuration would be to create two security groups:

Server-SG: Allow SSH or RDP access (as appropriate) from 0.0.0.0/0 (or less, if possible, for better security). Associate it to the EC2 instance.
Database-SG: Allow access (eg port 3306 if MySQL) with the Source set to Server-SG. Associate it to the RDS instance.

This means that the Database security group will accept incoming connections from any EC2 instance that is associated with Server-SG.

When connecting to the database, use the DNS Name provided in the RDS console.