I have a rails app, that I am currently shifting to production. But I want to setup a subdomain such that, if I goto : dev.myapp.com , I reach the development environment & if I goto prod.myapp.com , I reach the production environment
Will I have to use 2 instances for this purpose, or can this managed by one?
My servers are on AWS, and domain is managed by GoDaddy
You can definitely use both environments on the same server but you would have to have 2 different instances running.
You can use nginx or Apache HTTPD to route the different domains (or sub-domains) to the actual instance running on your server (if it's an AWS EC2).
You have several other ways to configure it depending on your setup.