Output updates to only specific users

Question

I am trying to figure out how some sites manage their versions and make seamless updates to their code, with minimal service disruptions and also about how sites like Google and Netflix roll-out new features for limited users to test them out before doing a full roll out.

I am looking for general ideas on how this happens, so any links to resources or explanations would be appreciated.

Thank You!

Answer 1

Have a test server and a live server, work out your code on your test and when it is done, boom, bing bang in seconds you replace your old files with the new files and in seconds it is done.

as for limited roll outs, in your database, you could make a field called something like eligible and have it set to 0 for no and 1 for yes. All those with yes selected will show different code or your test features.