I have a master MySQL instance running on our local network, but I was wondering if I can get an EC2 RDS instance to replicate the master or is this locked down by amazon?
Mysql – Is it possible to use an EC2 RDS MySQL instance as a slave to an external master
amazon ec2master-slaveMySQLreplication
Best Answer
Apparently this is now possible, however it is not fully "supported". Amazon will now allow you to replicate an RDS to an external slave, and replicate to an RDS from an external master, however their disclaimer suggests that they don't intend for this to be a permanent part of your server setup.
I have personally not tested this, but I plan on using it to help migrate off of some old non-AWS servers in which I host various databases and applications.
Given your question the below AWS doc will best apply.
Replication to RDS from external Master: http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/MySQL.Procedural.Importing.NonRDSRepl.html
Proof of concept on Sönke Ruempler's blog post (RDS to External Slave): http://www.ruempler.eu/2013/07/07/replicating-aws-rds-mysql-databases-to-external-slaves/