A while back we did an audit of what we were spending through Amazon Web Services to see if there was any way we could reduce our spending without having a negative impact on our users.
One of the big things we found we would be able to do was upgrade some of our production EC2 instances from for AWS’s older m1.medium to an m3.medium, and our dev/test instances could downgrade from m1.small to t2.small.
The catch was we needed to create those instances in AWS’s Virtual Private Network (VPC), and there is no documentation for how to connect that VPC to things running “Classic Mode”. Our database was running on a RDS instance that was in Classic Mode and we didn’t want to incur the downtime to move that to a VPC.
Here’s how we eventually were able to get our VPC instance to talk to our classic mode RDS.