If I understand correctly, you want to learn more about the processes Heroku handles on your behalf? There are a few things you could do to get more familiar with the underlying tech:
) Deploy your application to AWS instead of Heroku. This will give you more understanding of what "magic" Heroku does on your behalf. Start with EC2, then build up to Elastic Beanstalk, which is rather similar to Heroku's offering. Also learn about Elastic Load Balancers and Auto Scaling.
) Learn the Xen hypervisor if you want to know what AWS is doing under the hood.
) Deploy your application to AWS instead of Heroku. This will give you more understanding of what "magic" Heroku does on your behalf. Start with EC2, then build up to Elastic Beanstalk, which is rather similar to Heroku's offering. Also learn about Elastic Load Balancers and Auto Scaling.
) Learn the Xen hypervisor if you want to know what AWS is doing under the hood.
) Cloud Application Architectures is an interesting read - http://www.amazon.com/Cloud-Application-Architectures-Applic...
) AWS System Administration will also (hopefully) be an interesting read, but I need to finish writing it first :P