Our applications are hosted in Rackspace dedicated servers. We are planning to move them to AWS services like EC2, S3, etc. Currently Rackspace takes care of backing up data, monitoring stuff, I don't know what else.
So, my questions is what are the things that we should do ourselves or outsource to other companies like Percona? Can someone list down the things?
Well, you'll have to do all the things Rackspace did and Amazon don't and that you need, of course. What this list includes is totally up to you.
One hint: Given the recent outage with data loss on AWS, it's a very good idea to make sure you don't put all your eggs in one basket, especially concerning backup. So, don't just do a backup with some AWS services, but make an offsite backup and make sure your backup vendor don't use AWS himself for storing the backups.
(The same is true for any vendor of course, I point out Amazon because of the recent history and your plan to use their service.)